# HG changeset patch # User mduigou # Date 1365709903 25200 # Node ID f42144dc96e535d1061c8871b5d34cabc532b2eb # Parent 863da64214e826577e48d3aed0b5cfcd858e5595 8004518: Add in-place operations to Map 8010122: Add defaults for ConcurrentMap operations to Map Reviewed-by: darcy, briangoetz, mduigou, dholmes, ulfzibis Contributed-by: Doug Lea
, Henry Jen , Akhil Arora , Peter Levart diff --git a/src/share/classes/java/util/Collections.java b/src/share/classes/java/util/Collections.java --- a/src/share/classes/java/util/Collections.java +++ b/src/share/classes/java/util/Collections.java @@ -28,6 +28,9 @@ import java.io.ObjectOutputStream; import java.io.IOException; import java.lang.reflect.Array; +import java.util.function.BiConsumer; +import java.util.function.BiFunction; +import java.util.function.Function; /** * This class consists exclusively of static methods that operate on or return @@ -1391,6 +1394,67 @@ public int hashCode() {return m.hashCode();} public String toString() {return m.toString();} + // Override default methods in Map + @Override + @SuppressWarnings("unchecked") + public V getOrDefault(Object k, V defaultValue) { + // Safe cast as we don't change the value + return ((Map) m).getOrDefault(k, defaultValue); + } + + @Override + public void forEach(BiConsumer action) { + m.forEach(action); + } + + @Override + public void replaceAll(BiFunction function) { + throw new UnsupportedOperationException(); + } + + @Override + public V putIfAbsent(K key, V value) { + throw new UnsupportedOperationException(); + } + + @Override + public boolean remove(Object key, Object value) { + throw new UnsupportedOperationException(); + } + + @Override + public boolean replace(K key, V oldValue, V newValue) { + throw new UnsupportedOperationException(); + } + + @Override + public V replace(K key, V value) { + throw new UnsupportedOperationException(); + } + + @Override + public V computeIfAbsent(K key, Function mappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V computeIfPresent(K key, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V compute(K key, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V merge(K key, V value, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + /** * We need this class in addition to UnmodifiableSet as * Map.Entries themselves permit modification of the backing Map @@ -1590,9 +1654,9 @@ * * Failure to follow this advice may result in non-deterministic behavior. * - *

The returned collection does not pass the hashCode - * and equals operations through to the backing collection, but - * relies on Object's equals and hashCode methods. This is + *

The returned collection does not pass the {@code hashCode} + * and {@code equals} operations through to the backing collection, but + * relies on {@code Object}'s equals and hashCode methods. This is * necessary to preserve the contracts of these operations in the case * that the backing collection is a set or a list.

* @@ -2107,6 +2171,53 @@ public String toString() { synchronized (mutex) {return m.toString();} } + + // Override default methods in Map + @Override + public V getOrDefault(Object k, V defaultValue) { + synchronized (mutex) {return m.getOrDefault(k, defaultValue);} + } + @Override + public void forEach(BiConsumer action) { + synchronized (mutex) {m.forEach(action);} + } + @Override + public void replaceAll(BiFunction function) { + synchronized (mutex) {m.replaceAll(function);} + } + @Override + public V putIfAbsent(K key, V value) { + synchronized (mutex) {return m.putIfAbsent(key, value);} + } + @Override + public boolean remove(Object key, Object value) { + synchronized (mutex) {return m.remove(key, value);} + } + @Override + public boolean replace(K key, V oldValue, V newValue) { + synchronized (mutex) {return m.replace(key, oldValue, newValue);} + } + @Override + public V replace(K key, V value) { + synchronized (mutex) {return m.replace(key, value);} + } + @Override + public V computeIfAbsent(K key, Function mappingFunction) { + synchronized (mutex) {return m.computeIfAbsent(key, mappingFunction);} + } + @Override + public V computeIfPresent(K key, BiFunction remappingFunction) { + synchronized (mutex) {return m.computeIfPresent(key, remappingFunction);} + } + @Override + public V compute(K key, BiFunction remappingFunction) { + synchronized (mutex) {return m.compute(key, remappingFunction);} + } + @Override + public V merge(K key, V value, BiFunction remappingFunction) { + synchronized (mutex) {return m.merge(key, value, remappingFunction);} + } + private void writeObject(ObjectOutputStream s) throws IOException { synchronized (mutex) {s.defaultWriteObject();} } @@ -2782,6 +2893,70 @@ return entrySet; } + // Override default methods in Map + @Override + public void forEach(BiConsumer action) { + m.forEach(action); + } + + @Override + public void replaceAll(BiFunction function) { + m.replaceAll(typeCheck(function)); + } + + @Override + public V putIfAbsent(K key, V value) { + typeCheck(key, value); + return m.putIfAbsent(key, value); + } + + @Override + public boolean remove(Object key, Object value) { + return m.remove(key, value); + } + + @Override + public boolean replace(K key, V oldValue, V newValue) { + typeCheck(key, newValue); + return m.replace(key, oldValue, newValue); + } + + @Override + public V replace(K key, V value) { + typeCheck(key, value); + return m.replace(key, value); + } + + @Override + public V computeIfAbsent(K key, Function mappingFunction) { + Objects.requireNonNull(mappingFunction); + return m.computeIfAbsent(key, k -> { + V value = mappingFunction.apply(k); + typeCheck(k, value); + return value; + }); + } + + @Override + public V computeIfPresent(K key, BiFunction remappingFunction) { + return m.computeIfPresent(key, typeCheck(remappingFunction)); + } + + @Override + public V compute(K key, BiFunction remappingFunction) { + return m.compute(key, typeCheck(remappingFunction)); + } + + @Override + public V merge(K key, V value, BiFunction remappingFunction) { + Objects.requireNonNull(remappingFunction); + return m.merge(key, value, (v1, v2) -> { + V newValue = remappingFunction.apply(v1, v2); + typeCheck(null, newValue); + return newValue; + }); + } + /** * We need this class in addition to CheckedSet as Map.Entry permits * modification of the backing Map via the setValue operation. This @@ -3456,6 +3631,66 @@ public int hashCode() {return 0;} + // Override default methods in Map + @Override + @SuppressWarnings("unchecked") + public V getOrDefault(Object k, V defaultValue) { + return defaultValue; + } + + @Override + public void forEach(BiConsumer action) { + Objects.requireNonNull(action); + } + + @Override + public void replaceAll(BiFunction function) { + throw new UnsupportedOperationException(); + } + + @Override + public V putIfAbsent(K key, V value) { + throw new UnsupportedOperationException(); + } + + @Override + public boolean remove(Object key, Object value) { + throw new UnsupportedOperationException(); + } + + @Override + public boolean replace(K key, V oldValue, V newValue) { + throw new UnsupportedOperationException(); + } + + @Override + public V replace(K key, V value) { + throw new UnsupportedOperationException(); + } + + @Override + public V computeIfAbsent(K key, Function mappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V computeIfPresent(K key, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V compute(K key, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V merge(K key, V value, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + // Preserves singleton property private Object readResolve() { return EMPTY_MAP; @@ -3619,6 +3854,64 @@ return values; } + // Override default methods in Map + @Override + public V getOrDefault(Object key, V defaultValue) { + return eq(key, k) ? v : defaultValue; + } + + @Override + public void forEach(BiConsumer action) { + action.accept(k, v); + } + + @Override + public void replaceAll(BiFunction function) { + throw new UnsupportedOperationException(); + } + + @Override + public V putIfAbsent(K key, V value) { + throw new UnsupportedOperationException(); + } + + @Override + public boolean remove(Object key, Object value) { + throw new UnsupportedOperationException(); + } + + @Override + public boolean replace(K key, V oldValue, V newValue) { + throw new UnsupportedOperationException(); + } + + @Override + public V replace(K key, V value) { + throw new UnsupportedOperationException(); + } + + @Override + public V computeIfAbsent(K key, Function mappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V computeIfPresent(K key, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V compute(K key, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } + + @Override + public V merge(K key, V value, + BiFunction remappingFunction) { + throw new UnsupportedOperationException(); + } } // Miscellaneous diff --git a/src/share/classes/java/util/HashMap.java b/src/share/classes/java/util/HashMap.java --- a/src/share/classes/java/util/HashMap.java +++ b/src/share/classes/java/util/HashMap.java @@ -1,5 +1,5 @@ /* - * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -24,7 +24,11 @@ */ package java.util; + import java.io.*; +import java.util.function.Consumer; +import java.util.function.BiFunction; +import java.util.function.Function; /** * Hash table based implementation of the Map interface. This @@ -350,6 +354,13 @@ return null == entry ? null : entry.getValue(); } + @Override + public V getOrDefault(Object key, V defaultValue) { + Entry entry = getEntry(key); + + return null == entry ? defaultValue : entry.getValue(); + } + /** * Returns true if this map contains a mapping for the * specified key. @@ -567,6 +578,238 @@ return (e == null ? null : e.value); } + // optimized implementations of default methods in Map + + @Override + public V putIfAbsent(K key, V value) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry e = (Entry)table[i]; + for(; e != null; e = e.next) { + if (e.hash == hash && Objects.equals(e.key, key)) { + if(e.value != null) { + return e.value; + } + e.value = value; + modCount++; + e.recordAccess(this); + return null; + } + } + + modCount++; + addEntry(hash, key, value, i); + return null; + } + + @Override + public boolean remove(Object key, Object value) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry prev = (Entry)table[i]; + Entry e = prev; + + while (e != null) { + Entry next = e.next; + if (e.hash == hash && Objects.equals(e.key, key)) { + if(!Objects.equals(e.value, value)) { + return false; + } + modCount++; + size--; + if (prev == e) + table[i] = next; + else + prev.next = next; + e.recordRemoval(this); + return true; + } + prev = e; + e = next; + } + + return false; + } + + @Override + public boolean replace(K key, V oldValue, V newValue) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry e = (Entry)table[i]; + for(; e != null; e = e.next) { + if (e.hash == hash && Objects.equals(e.key, key) && Objects.equals(e.value, oldValue)) { + e.value = newValue; + e.recordAccess(this); + return true; + } + } + + return false; + } + + @Override + public V replace(K key, V value) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry e = (Entry)table[i]; + for(; e != null; e = e.next) { + if (e.hash == hash && Objects.equals(e.key, key)) { + V oldValue = e.value; + e.value = value; + e.recordAccess(this); + return oldValue; + } + } + + return null; + } + + @Override + public V computeIfAbsent(K key, Function mappingFunction) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry e = (Entry)table[i]; + for(; e != null; e = e.next) { + if (e.hash == hash && Objects.equals(e.key, key)) { + V oldValue = e.value; + return oldValue == null ? (e.value = mappingFunction.apply(key)) : oldValue; + } + } + + V newValue = mappingFunction.apply(key); + if (newValue != null) { + modCount++; + addEntry(hash, key, newValue, i); + } + + return newValue; + } + + @Override + public V computeIfPresent(K key, BiFunction remappingFunction) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry prev = (Entry)table[i]; + Entry e = prev; + + while (e != null) { + Entry next = e.next; + if (e.hash == hash && Objects.equals(e.key, key)) { + V oldValue = e.value; + if (oldValue == null) + break; + V newValue = remappingFunction.apply(key, oldValue); + modCount++; + if (newValue == null) { + size--; + if (prev == e) + table[i] = next; + else + prev.next = next; + e.recordRemoval(this); + } + else { + e.value = newValue; + e.recordAccess(this); + } + return newValue; + } + prev = e; + e = next; + } + + return null; + } + + @Override + public V compute(K key, BiFunction remappingFunction) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry prev = (Entry)table[i]; + Entry e = prev; + + while (e != null) { + Entry next = e.next; + if (e.hash == hash && Objects.equals(e.key, key)) { + V oldValue = e.value; + V newValue = remappingFunction.apply(key, oldValue); + if (newValue != oldValue) { + modCount++; + if (newValue == null) { + size--; + if (prev == e) + table[i] = next; + else + prev.next = next; + e.recordRemoval(this); + } else { + e.value = newValue; + e.recordAccess(this); + } + } + return newValue; + } + prev = e; + e = next; + } + + V newValue = remappingFunction.apply(key, null); + if (newValue != null) { + modCount++; + addEntry(hash, key, newValue, i); + } + + return newValue; + } + + @Override + public V merge(K key, V value, BiFunction remappingFunction) { + int hash = (key == null) ? 0 : hash(key); + int i = indexFor(hash, table.length); + @SuppressWarnings("unchecked") + Entry prev = (Entry)table[i]; + Entry e = prev; + + while (e != null) { + Entry next = e.next; + if (e.hash == hash && Objects.equals(e.key, key)) { + V oldValue = e.value; + V newValue = remappingFunction.apply(oldValue, value); + modCount++; + if (newValue == null) { + size--; + if (prev == e) + table[i] = next; + else + prev.next = next; + e.recordRemoval(this); + } else { + e.value = newValue; + e.recordAccess(this); + } + return newValue; + } + prev = e; + e = next; + } + + if (value != null) { + modCount++; + addEntry(hash, key, value, i); + } + + return value; + } + + // end of optimized implementations of default methods in Map + /** * Removes and returns the entry associated with the specified key * in the HashMap. Returns null if the HashMap contains no mapping diff --git a/src/share/classes/java/util/Hashtable.java b/src/share/classes/java/util/Hashtable.java --- a/src/share/classes/java/util/Hashtable.java +++ b/src/share/classes/java/util/Hashtable.java @@ -1,5 +1,5 @@ /* - * Copyright (c) 1994, 2012, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1994, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -24,7 +24,10 @@ */ package java.util; + import java.io.*; +import java.util.function.Function; +import java.util.function.BiFunction; /** * This class implements a hash table, which maps keys to values. Any @@ -455,6 +458,26 @@ } } + private void addEntry(int hash, K key, V value, int index) { + modCount++; + + Entry tab[] = table; + if (count >= threshold) { + // Rehash the table if the threshold is exceeded + rehash(); + + tab = table; + hash = hash(key); + index = (hash & 0x7FFFFFFF) % tab.length; + } + + // Creates the new entry. + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + tab[index] = new Entry<>(hash, key, value, e); + count++; + } + /** * Maps the specified key to the specified * value in this hashtable. Neither the key nor the @@ -492,21 +515,7 @@ } } - modCount++; - if (count >= threshold) { - // Rehash the table if the threshold is exceeded - rehash(); - - tab = table; - hash = hash(key); - index = (hash & 0x7FFFFFFF) % tab.length; - } - - // Creates the new entry. - @SuppressWarnings("unchecked") - Entry e = (Entry)tab[index]; - tab[index] = new Entry<>(hash, key, value, e); - count++; + addEntry(hash, key, value, index); return null; } @@ -892,6 +901,227 @@ return h; } + @Override + public synchronized V getOrDefault(Object key, V defaultValue) { + V result = get(key); + return (null == result) ? defaultValue : result; + } + + @Override + public synchronized void replaceAll( + BiFunction function) + { + Map.super.replaceAll(function); + } + + @Override + public synchronized V putIfAbsent(K key, V value) { + Objects.requireNonNull(value); + + // Makes sure the key is not already in the hashtable. + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry entry = (Entry)tab[index]; + for(; entry != null ; entry = entry.next) { + if ((entry.hash == hash) && entry.key.equals(key)) { + V old = entry.value; + if (old == null) { + entry.value = value; + } + return old; + } + } + + addEntry(hash, key, value, index); + return null; + } + + @Override + public synchronized boolean remove(Object key, Object value) { + Objects.requireNonNull(value); + + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry)tab[index]; + for(Entry prev = null ; e != null ; prev = e, e = e.next) { + if ((e.hash == hash) && e.key.equals(key) && e.value.equals(value)) { + modCount++; + if (prev != null) { + prev.next = e.next; + } else { + tab[index] = e.next; + } + count--; + e.value = null; + return true; + } + } + return false; + } + + @Override + public synchronized boolean replace(K key, V oldValue, V newValue) { + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + for (; e != null ; e = e.next) { + if ((e.hash == hash) && e.key.equals(key)) { + if (e.value.equals(oldValue)) { + e.value = newValue; + return true; + } else { + return false; + } + } + } + return false; + } + + @Override + public synchronized V replace(K key, V value) { + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + for (; e != null; e = e.next) { + if ((e.hash == hash) && e.key.equals(key)) { + V oldValue = e.value; + e.value = value; + return oldValue; + } + } + return null; + } + + @Override + public synchronized V computeIfAbsent(K key, Function mappingFunction) { + Objects.requireNonNull(mappingFunction); + + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + for(; e != null; e = e.next) { + if (e.hash == hash && e.key.equals(key)) { + // Hashtable not accept null value + return e.value; + } + } + + V newValue = mappingFunction.apply(key); + if (newValue != null) { + addEntry(hash, key, newValue, index); + } + + return newValue; + } + + @Override + public V computeIfPresent(K key, BiFunction remappingFunction) { + Objects.requireNonNull(remappingFunction); + + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + for(Entry prev = null; e != null; prev = e, e = e.next) { + if (e.hash == hash && e.key.equals(key)) { + V newValue = remappingFunction.apply(key, e.value); + if (newValue == null) { + modCount++; + if (prev != null) { + prev.next = e.next; + } else { + tab[index] = e.next; + } + count--; + } else { + e.value = newValue; + } + return newValue; + } + } + return null; + } + + @Override + public V compute(K key, BiFunction remappingFunction) { + Objects.requireNonNull(remappingFunction); + + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + for(Entry prev = null; e != null; prev = e, e = e.next) { + if (e.hash == hash && Objects.equals(e.key, key)) { + V newValue = remappingFunction.apply(key, e.value); + if (newValue == null) { + modCount++; + if (prev != null) { + prev.next = e.next; + } else { + tab[index] = e.next; + } + count--; + } else { + e.value = newValue; + } + return newValue; + } + } + + V newValue = remappingFunction.apply(key, null); + if (newValue != null) { + addEntry(hash, key, newValue, index); + } + + return newValue; + } + + @Override + public V merge(K key, V value, BiFunction remappingFunction) { + Objects.requireNonNull(remappingFunction); + + Entry tab[] = table; + int hash = hash(key); + int index = (hash & 0x7FFFFFFF) % tab.length; + @SuppressWarnings("unchecked") + Entry e = (Entry) tab[index]; + for(Entry prev = null; e != null; prev = e, e = e.next) { + if (e.hash == hash && e.key.equals(key)) { + V newValue = remappingFunction.apply(e.value, value); + if (newValue == null) { + modCount++; + if (prev != null) { + prev.next = e.next; + } else { + tab[index] = e.next; + } + count--; + } else { + e.value = newValue; + } + return newValue; + } + } + + if (value != null) { + addEntry(hash, key, value, index); + } + + return value; + } + /** * Save the state of the Hashtable to a stream (i.e., serialize it). * diff --git a/src/share/classes/java/util/Map.java b/src/share/classes/java/util/Map.java --- a/src/share/classes/java/util/Map.java +++ b/src/share/classes/java/util/Map.java @@ -1,5 +1,5 @@ /* - * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it @@ -25,6 +25,10 @@ package java.util; +import java.util.function.BiConsumer; +import java.util.function.BiFunction; +import java.util.function.Function; + /** * An object that maps keys to values. A map cannot contain duplicate keys; * each key can map to at most one value. @@ -475,4 +479,597 @@ */ int hashCode(); + // Defaultable methods + + /** + * Returns the value to which the specified key is mapped, + * or {@code defaultValue} if this map contains no mapping + * for the key. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @param key the key whose associated value is to be returned + * @return the value to which the specified key is mapped, or + * {@code defaultValue} if this map contains no mapping for the key + * @throws ClassCastException if the key is of an inappropriate type for + * this map + * (optional) + * @throws NullPointerException if the specified key is null and this map + * does not permit null keys + * (optional) + */ + default V getOrDefault(Object key, V defaultValue) { + V v; + return (((v = get(key)) != null) || containsKey(key)) + ? v + : defaultValue; + } + + /** + * Performs the given action on each entry in this map, in the + * order entries are returned by an entry set iterator, until all entries + * have been processed or the action throws an {@code Exception}. + * Exceptions thrown by the action are relayed to the caller. + * + *

The default implementation should be overridden by implementations if + * they can provide a more performant implementation than an iterator-based + * one. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @implSpec The default implementation is equivalent to, for this + * {@code map}: + * 

 {@code
+     *     for ((Map.Entry entry : map.entrySet())
+     *         action.accept(entry.getKey(), entry.getValue());
+     * }
+ * + * @param action The action to be performed for each entry + * @throws NullPointerException if the specified action is null + * @throws ConcurrentModificationException if an entry is found to be + * removed during iteration + * @since 1.8 + */ + default void forEach(BiConsumer action) { + Objects.requireNonNull(action); + for (Map.Entry entry : entrySet()) { + K k; + V v; + try { + k = entry.getKey(); + v = entry.getValue(); + } catch(IllegalStateException ise) { + throw new ConcurrentModificationException(ise); + } + action.accept(k, v); + } + } + + /** + * Replaces each entry's value with the result of invoking the given + * function on that entry, in the order entries are returned by an entry + * set iterator, until all entries have been processed or the function + * throws an exception. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @implSpec + *

The default implementation is equivalent to, for this {@code map}: + * 

 {@code
+     *     for ((Map.Entry entry : map.entrySet())
+     *         entry.setValue(function.apply(entry.getKey(), entry.getValue()));
+     * }
+ * + * @param function the function to apply to each entry + * @throws UnsupportedOperationException if the {@code set} operation + * is not supported by this map's entry set iterator. + * @throws ClassCastException if the class of a replacement value + * prevents it from being stored in this map + * @throws NullPointerException if the specified function is null, or the + * specified replacement value is null, and this map does not permit null + * values + * @throws ClassCastException if a replacement value is of an inappropriate + * type for this map + * (optional) + * @throws NullPointerException if function or a replacement value is null, + * and this map does not permit null keys or values + * (optional) + * @throws IllegalArgumentException if some property of a replacement value + * prevents it from being stored in this map + * (optional) + * @throws ConcurrentModificationException if an entry is found to be + * removed during iteration + * @since 1.8 + */ + default void replaceAll(BiFunction function) { + Objects.requireNonNull(function); + for (Map.Entry entry : entrySet()) { + K k; + V v; + try { + k = entry.getKey(); + v = entry.getValue(); + } catch(IllegalStateException ise) { + throw new ConcurrentModificationException(ise); + } + entry.setValue(function.apply(k, v)); + } + } + + /** + * If the specified key is not already associated with a value (or is mapped + * to {@code null}) associates it with the given value and returns + * {@code null}, else returns the current value. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @implSpec + * The default implementation is equivalent to, for this {@code + * map}: + * + * 

 {@code
+     * if (map.get(key) == null)
+     *   return map.put(key, value);
+     * else
+     *   return map.get(key);}
+ * + * @param key key with which the specified value is to be associated + * @param value value to be associated with the specified key + * @return the previous value associated with the specified key, or + * {@code 1} if there was no mapping for the key. + * (A {@code null} return can also indicate that the map + * previously associated {@code null} with the key, + * if the implementation supports null values.) + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the key or value is of an inappropriate + * type for this map + * (optional) + * @throws NullPointerException if the specified key or value is null, + * and this map does not permit null keys or values + * (optional) + * @throws IllegalArgumentException if some property of the specified key + * or value prevents it from being stored in this map + * (optional) + * @throws ConcurrentModificationException if a modification of the map is + * detected during insertion of the value. + * @since 1.8 + */ + default V putIfAbsent(K key, V value) { + V v = get(key); + if (v == null) { + if (put(key, value) != null) { + throw new ConcurrentModificationException(); + } + } + + return v; + } + + /** + * Removes the entry for the specified key only if it is currently + * mapped to the specified value. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @implSpec + * The default implementation is equivalent to, for this {@code map}: + * + * 

 {@code
+     * if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
+     *   map.remove(key);
+     *   return true;
+     * } else
+     *   return false;}
+ * + * @param key key with which the specified value is associated + * @param value value expected to be associated with the specified key + * @return {@code true} if the value was removed + * @throws UnsupportedOperationException if the {@code remove} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the key or value is of an inappropriate + * type for this map + * (optional) + * @throws NullPointerException if the specified key or value is null, + * and this map does not permit null keys or values + * (optional) + * @since 1.8 + */ + default boolean remove(Object key, Object value) { + if (!Objects.equals(get(key), value) || !containsKey(key)) + return false; + remove(key); + return true; + } + + /** + * Replaces the entry for the specified key only if currently + * mapped to the specified value. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @implSpec + * The default implementation is equivalent to, for this {@code map}: + * + * 

 {@code
+     * if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
+     *   map.put(key, newValue);
+     *   return true;
+     * } else
+     *   return false;}
+ * + * @param key key with which the specified value is associated + * @param oldValue value expected to be associated with the specified key + * @param newValue value to be associated with the specified key + * @return {@code true} if the value was replaced + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the class of a specified key or value + * prevents it from being stored in this map + * @throws NullPointerException if a specified key or value is null, + * and this map does not permit null keys or values + * @throws IllegalArgumentException if some property of a specified key + * or value prevents it from being stored in this map + * @since 1.8 + */ + default boolean replace(K key, V oldValue, V newValue) { + if (!containsKey(key) || !Objects.equals(get(key), oldValue)) + return false; + put(key, newValue); + return true; + } + + /** + * Replaces the entry for the specified key only if it is + * currently mapped to some value. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. + * + * @implSpec + * The default implementation is equivalent to, for this {@code map}: + * + * 

 {@code
+     * if (map.containsKey(key)) {
+     *   return map.put(key, value);
+     * } else
+     *   return null;}
+ * + * @param key key with which the specified value is associated + * @param value value to be associated with the specified key + * @return the previous value associated with the specified key, or + * {@code null} if there was no mapping for the key. + * (A {@code null} return can also indicate that the map + * previously associated {@code null} with the key, + * if the implementation supports null values.) + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the class of the specified key or value + * prevents it from being stored in this map + * (optional) + * @throws NullPointerException if the specified key or value is null, + * and this map does not permit null keys or values + * @throws IllegalArgumentException if some property of the specified key + * or value prevents it from being stored in this map + * @since 1.8 + */ + default V replace(K key, V value) { + return containsKey(key) ? put(key, value) : null; + } + + /** + * If the specified key is not already associated with a value (or + * is mapped to {@code null}), attempts to compute its value using + * the given mapping function and enters it into this map unless + * {@code null}. + * + *

If the function returns {@code null} no mapping is recorded. If + * the function itself throws an (unchecked) exception, the + * exception is rethrown, and no mapping is recorded. The most + * common usage is to construct a new object serving as an initial + * mapped value or memoized result, as in: + * + * 

 {@code
+     * map.computeIfAbsent(key, k -> new Value(f(k)));}
+ * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. In particular, all implementations of + * subinterface {@link java.util.concurrent.ConcurrentMap} must document + * whether the function is applied once atomically only if the value is not + * present. Any class that permits null values must document + * whether and how this method distinguishes absence from null mappings. + * + * @implSpec + * The default implementation is equivalent to the following + * steps for this {@code map}, then returning the current value or + * {@code null} if now absent: + * + * 

 {@code
+     * if (map.get(key) == null) {
+     *   V newValue = mappingFunction.apply(key);
+     *   if (newValue != null)
+     *      map.putIfAbsent(key, newValue);
+     * }}
+ * + * @param key key with which the specified value is to be associated + * @param mappingFunction the function to compute a value + * @return the current (existing or computed) value associated with + * the specified key, or null if the computed value is null + * @throws NullPointerException if the specified key is null and + * this map does not support null keys, or the + * mappingFunction is null + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the class of the specified key or value + * prevents it from being stored in this map + * (optional) + * @since 1.8 + */ + default V computeIfAbsent(K key, Function mappingFunction) { + V v, newValue; + return ((v = get(key)) == null && + (newValue = mappingFunction.apply(key)) != null && + (v = putIfAbsent(key, newValue)) == null) ? newValue : v; + } + + /** + * If the value for the specified key is present and non-null, attempts to + * compute a new mapping given the key and its current mapped value. + * + *

If the function returns {@code null}, the mapping is removed. If the + * function itself throws an (unchecked) exception, the exception is + * rethrown, and the current mapping is left unchanged. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. In particular, all implementations of + * subinterface {@link java.util.concurrent.ConcurrentMap} must document + * whether the function is applied once atomically only if the value is not + * present. Any class that permits null values must document + * whether and how this method distinguishes absence from null mappings. + * + * @implSpec + * The default implementation is equivalent to performing the + * following steps for this {@code map}, then returning the + * current value or {@code null} if now absent: + * + * 

 {@code
+     * if (map.get(key) != null) {
+     *   V oldValue = map.get(key);
+     *   V newValue = remappingFunction.apply(key, oldValue);
+     *   if (newValue != null)
+     *     map.replace(key, oldValue, newValue);
+     *   else
+     *     map.remove(key, oldValue);
+     * }}
+ * + * In concurrent contexts, the default implementation may retry + * these steps when multiple threads attempt updates. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key is null and + * this map does not support null keys, or the + * remappingFunction is null + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the class of the specified key or value + * prevents it from being stored in this map + * (optional) + * @since 1.8 + */ + default V computeIfPresent(K key, + BiFunction remappingFunction) { + V oldValue; + while ((oldValue = get(key)) != null) { + V newValue = remappingFunction.apply(key, oldValue); + if (newValue != null) { + if (replace(key, oldValue, newValue)) + return newValue; + } else if (remove(key, oldValue)) + return null; + } + return oldValue; + } + + /** + * Attempts to compute a mapping for the specified key and its + * current mapped value (or {@code null} if there is no current + * mapping). For example, to either create or append a {@code + * String msg} to a value mapping: + * + * 
 {@code
+     * map.compute(key, (k, v) -> (v == null) ? msg : v.concat(msg))}
+ * (Method {@link #merge} is often simpler to use for such purposes.) + * + *

If the function returns {@code null}, the mapping is removed (or + * remains absent if initially absent). If the function itself throws an + * (unchecked) exception, the exception is rethrown, and the current mapping + * is left unchanged. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. In particular, all implementations of + * subinterface {@link java.util.concurrent.ConcurrentMap} must document + * whether the function is applied once atomically only if the value is not + * present. Any class that permits null values must document + * whether and how this method distinguishes absence from null mappings. + * + * @implSpec + * The default implementation is equivalent to performing the following + * steps for this {@code map}, then returning the current value or + * {@code null} if absent: + * + * 

{@code
+     * V oldValue = map.get(key);
+     * V newValue = remappingFunction.apply(key, oldValue);
+     * if (oldValue != null )
+     *    if (newValue != null)
+     *       map.replace(key, oldValue, newValue);
+     *    else
+     *       map.remove(key, oldValue);
+     * else
+     *    if (newValue != null)
+     *       map.putIfAbsent(key, newValue);
+     *    else
+     *       return null;
+     * }
+ * + * In concurrent contexts, the default implementation may retry + * these steps when multiple threads attempt updates. + * + * @param key key with which the specified value is to be associated + * @param remappingFunction the function to compute a value + * @return the new value associated with the specified key, or null if none + * @throws NullPointerException if the specified key is null and + * this map does not support null keys, or the + * remappingFunction is null + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the class of the specified key or value + * prevents it from being stored in this map + * (optional) + * @since 1.8 + */ + default V compute(K key, + BiFunction remappingFunction) { + V oldValue = get(key); + for (;;) { + V newValue = remappingFunction.apply(key, oldValue); + if (oldValue != null) { + if (newValue != null) { + if (replace(key, oldValue, newValue)) + return newValue; + } else if (remove(key, oldValue)) { + return null; + } + oldValue = get(key); + } else { + if (newValue != null) { + if ((oldValue = putIfAbsent(key, newValue)) == null) + return newValue; + } else { + return null; + } + } + } + } + + /** + * If the specified key is not already associated with a + * (non-null) value, associates it with the given value. + * Otherwise, replaces the value with the results of the given + * remapping function, or removes if {@code null}. This method may + * be of use when combining multiple mapped values for a key. For + * example, to either create or append a {@code String msg} to a + * value mapping: + * + * 
 {@code
+     * map.merge(key, msg, String::concat)}
+ * + *

If the function returns {@code null}, the mapping is removed (or + * remains absent if initially absent). If the function itself throws an + * (unchecked) exception, the exception is rethrown, and the current mapping + * is left unchanged. + * + *

The default implementation makes no guarantees about synchronization + * or atomicity properties of this method. Any implementation providing + * atomicity guarantees must override this method and document its + * concurrency properties. In particular, all implementations of + * subinterface {@link java.util.concurrent.ConcurrentMap} must document + * whether the function is applied once atomically only if the value is not + * present. Any class that permits null values must document + * whether and how this method distinguishes absence from null mappings. + * + * @implSpec + * The default implementation is equivalent to performing the + * following steps for this {@code map}, then returning the + * current value or {@code null} if absent: + * + * 

 {@code
+     * V oldValue = map.get(key);
+     * V newValue = (oldValue == null) ? value :
+     *              remappingFunction.apply(oldValue, value);
+     * if (newValue == null)
+     *   map.remove(key, oldValue);
+     * else if (oldValue == null)
+     *   map.putIfAbsent(key, newValue);
+     * else
+     *   map.replace(key, oldValue, newValue);
+     * }
+ * + * In concurrent contexts, the default implementation may retry + * these steps when multiple threads attempt updates. + * + * @param key key with which the specified value is to be associated + * @param value the value to use if absent + * @param remappingFunction the function to recompute a value if present + * @return the new value associated with the specified key, or null if none + * @throws UnsupportedOperationException if the {@code put} operation + * is not supported by this map + * (optional) + * @throws ClassCastException if the class of the specified key or value + * prevents it from being stored in this map + * (optional) + * @throws NullPointerException if the specified key is null and + * this map does not support null keys, or the + * remappingFunction is null + * @since 1.8 + */ + default V merge(K key, V value, + BiFunction remappingFunction) { + V oldValue = get(key); + for (;;) { + if (oldValue != null) { + V newValue = remappingFunction.apply(oldValue, value); + if (newValue != null) { + if (replace(key, oldValue, newValue)) + return newValue; + } else if (remove(key, oldValue)) { + return null; + } + oldValue = get(key); + } else { + if (value == null) { + return null; + } + + if ((oldValue = putIfAbsent(key, value)) == null) { + return value; + } + } + } + } } diff --git a/src/share/classes/java/util/concurrent/ConcurrentMap.java b/src/share/classes/java/util/concurrent/ConcurrentMap.java --- a/src/share/classes/java/util/concurrent/ConcurrentMap.java +++ b/src/share/classes/java/util/concurrent/ConcurrentMap.java @@ -38,7 +38,7 @@ /** * A {@link java.util.Map} providing additional atomic - * putIfAbsent, remove, and replace methods. + * {@code putIfAbsent}, {@code remove}, and {@code replace} methods. * *

Memory consistency effects: As with other concurrent * collections, actions in a thread prior to placing an object into a @@ -57,6 +57,21 @@ * @param the type of mapped values */ public interface ConcurrentMap extends Map { + + /** + * {@inheritDoc} + * + * @implNote This implementation assumes that the ConcurrentMap cannot + * contain null values and get() returning null unambiguously means no + * mapping is present. Implementations which support null values must + * override this default implementation. + */ + @Override + default V getOrDefault(Object key, V defaultValue) { + V v; + return (null != (v = get(key))) ? v : defaultValue; + } + /** * If the specified key is not already associated * with a value, associate it with the given value. @@ -91,7 +106,7 @@ * Removes the entry for a key only if currently mapped to a given value. * This is equivalent to * 

 {@code
-     * if (map.containsKey(key) && map.get(key).equals(value)) {
+     * if (map.containsKey(key) && Objects.equals(map.get(key), value)) {
      *   map.remove(key);
      *   return true;
      * } else
@@ -101,8 +116,8 @@
      *
      * @param key key with which the specified value is associated
      * @param value value expected to be associated with the specified key
-     * @return true if the value was removed
-     * @throws UnsupportedOperationException if the remove operation
+     * @return {@code true} if the value was removed
+     * @throws UnsupportedOperationException if the {@code remove} operation
      *         is not supported by this map
      * @throws ClassCastException if the key or value is of an inappropriate
      *         type for this map
@@ -117,7 +132,7 @@
      * Replaces the entry for a key only if currently mapped to a given value.
      * This is equivalent to
      *  
 {@code
-     * if (map.containsKey(key) && map.get(key).equals(oldValue)) {
+     * if (map.containsKey(key) && Objects.equals(map.get(key), oldValue)) {
      *   map.put(key, newValue);
      *   return true;
      * } else
@@ -128,8 +143,8 @@
      * @param key key with which the specified value is associated
      * @param oldValue value expected to be associated with the specified key
      * @param newValue value to be associated with the specified key
-     * @return true if the value was replaced
-     * @throws UnsupportedOperationException if the put operation
+     * @return {@code true} if the value was replaced
+     * @throws UnsupportedOperationException if the {@code put} operation
      *         is not supported by this map
      * @throws ClassCastException if the class of a specified key or value
      *         prevents it from being stored in this map
@@ -154,11 +169,11 @@
      * @param key key with which the specified value is associated
      * @param value value to be associated with the specified key
      * @return the previous value associated with the specified key, or
-     *         null if there was no mapping for the key.
-     *         (A null return can also indicate that the map
-     *         previously associated null with the key,
+     *         {@code null} if there was no mapping for the key.
+     *         (A {@code null} return can also indicate that the map
+     *         previously associated {@code null} with the key,
      *         if the implementation supports null values.)
-     * @throws UnsupportedOperationException if the put operation
+     * @throws UnsupportedOperationException if the {@code put} operation
      *         is not supported by this map
      * @throws ClassCastException if the class of the specified key or value
      *         prevents it from being stored in this map
diff --git a/test/java/util/Map/ToArray.java b/test/java/util/Map/Defaults.java
copy from test/java/util/Map/ToArray.java
copy to test/java/util/Map/Defaults.java
--- a/test/java/util/Map/ToArray.java
+++ b/test/java/util/Map/Defaults.java
@@ -23,165 +23,572 @@
 
 /*
  * @test
- * @bug 8008785
- * @summary Ensure toArray() implementations return correct results.
+ * @bug 8010122 8004518
+ * @summary Test Map default methods
  * @author Mike Duigou
+ * @run testng Defaults
  */
-import java.util.*;
+import java.util.AbstractMap;
+import java.util.AbstractSet;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumMap;
+import java.util.HashMap;
+import java.util.Hashtable;
+import java.util.IdentityHashMap;
+import java.util.Iterator;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import java.util.TreeMap;
+import java.util.Set;
+import java.util.WeakHashMap;
+import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentSkipListMap;
+import java.util.function.Supplier;
 
-public class ToArray {
+import org.testng.annotations.Test;
+import org.testng.annotations.DataProvider;
+import static org.testng.Assert.fail;
+import static org.testng.Assert.assertEquals;
+import static org.testng.Assert.assertTrue;
+import static org.testng.Assert.assertFalse;
+import static org.testng.Assert.assertNull;
+import static org.testng.Assert.assertSame;
+
+public class Defaults {
+
+    @Test(dataProvider = "Nulls Map")
+    public void testGetOrDefaultNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.get(null), map.getOrDefault(null, EXTRA_VALUE), "values should match");
+    }
+
+    @Test(dataProvider = "Map")
+    public void testGetOrDefault(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]), "expected key missing");
+        assertSame(map.get(KEYS[1]), map.getOrDefault(KEYS[1], EXTRA_VALUE), "values should match");
+        assertFalse(map.containsKey(EXTRA_KEY), "expected absent key");
+        assertSame(map.getOrDefault(EXTRA_KEY, EXTRA_VALUE), EXTRA_VALUE, "value not returned as default");
+        assertNull(map.getOrDefault(EXTRA_KEY, null), "null not returned as default");
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testPutIfAbsentNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertNull(map.putIfAbsent(null, EXTRA_VALUE), "previous not null");
+        assertTrue(map.containsKey(null), "null key absent");
+        assertSame(map.get(null), EXTRA_VALUE, "unexpected value");
+        assertSame(map.putIfAbsent(null, null), EXTRA_VALUE, "previous not expected value");
+        assertTrue(map.containsKey(null), "null key absent");
+        assertSame(map.get(null), EXTRA_VALUE, "unexpected value");
+        assertSame(map.remove(null), EXTRA_VALUE, "removed unexpected value");
+
+        assertFalse(map.containsKey(null), description + ": key present after remove");
+        assertNull(map.putIfAbsent(null, null), "previous not null");
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertNull(map.putIfAbsent(null, EXTRA_VALUE), "previous not null");
+        assertSame(map.get(null), EXTRA_VALUE, "value not expected");
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testPutIfAbsent(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertSame(map.putIfAbsent(KEYS[1], EXTRA_VALUE), expected);
+        assertSame(map.get(KEYS[1]), expected);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.putIfAbsent(EXTRA_KEY, EXTRA_VALUE), null);
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "Nulls Map")
+    public void testForEach(String description, Map map) {
+        IntegerEnum[] EACH_KEY = new IntegerEnum[map.size()];
+
+        map.forEach((k, v) -> {
+            int idx = (null == k) ? 0 : k.ordinal(); // substitute for index.
+            assertNull(EACH_KEY[idx]);
+            EACH_KEY[idx] = (idx == 0) ? KEYS[0] : k; // substitute for comparison.
+            assertSame(v, map.get(k));
+        });
+
+        assertEquals(KEYS, EACH_KEY);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public static void testRemoveNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertFalse(map.remove(null, EXTRA_VALUE), description);
+        assertTrue(map.containsKey(null));
+        assertNull(map.get(null));
+        assertTrue(map.remove(null, null));
+        assertFalse(map.containsKey(null));
+        assertNull(map.get(null));
+        assertFalse(map.remove(null, null));
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public static void testRemove(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertFalse(map.remove(KEYS[1], EXTRA_VALUE), description);
+        assertSame(map.get(KEYS[1]), expected);
+        assertTrue(map.remove(KEYS[1], expected));
+        assertNull(map.get(KEYS[1]));
+        assertFalse(map.remove(KEYS[1], expected));
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertFalse(map.remove(EXTRA_KEY, EXTRA_VALUE));
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testReplaceKVNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.replace(null, EXTRA_VALUE), null);
+        assertSame(map.get(null), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testReplaceKV(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertSame(map.replace(KEYS[1], EXTRA_VALUE), expected);
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertNull(map.replace(EXTRA_KEY, EXTRA_VALUE));
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertNull(map.get(EXTRA_KEY));
+        assertNull(map.put(EXTRA_KEY, EXTRA_VALUE));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+        assertSame(map.replace(EXTRA_KEY, (String)expected), EXTRA_VALUE);
+        assertSame(map.get(EXTRA_KEY), expected);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testReplaceKVVNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertFalse(map.replace(null, EXTRA_VALUE, EXTRA_VALUE));
+        assertNull(map.get(null));
+        assertTrue(map.replace(null, null, EXTRA_VALUE));
+        assertSame(map.get(null), EXTRA_VALUE);
+        assertTrue(map.replace(null, EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(null), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testReplaceKVV(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1]);
+        assertFalse(map.replace(KEYS[1], EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(KEYS[1]), expected);
+        assertTrue(map.replace(KEYS[1], (String)expected, EXTRA_VALUE));
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE);
+        assertTrue(map.replace(KEYS[1], EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertFalse(map.replace(EXTRA_KEY, EXTRA_VALUE, EXTRA_VALUE));
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertNull(map.get(EXTRA_KEY));
+        assertNull(map.put(EXTRA_KEY, EXTRA_VALUE));
+        assertTrue(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+        assertTrue(map.replace(EXTRA_KEY, EXTRA_VALUE, EXTRA_VALUE));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testComputeIfAbsentNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.computeIfAbsent(null, (k) -> EXTRA_VALUE), EXTRA_VALUE, description);
+        assertSame(map.get(null), EXTRA_VALUE, description);
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testComputeIfAbsent(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object expected = map.get(KEYS[1]);
+        assertTrue(null == expected || expected == VALUES[1], description + String.valueOf(expected));
+        expected = (null == expected) ? EXTRA_VALUE : expected;
+        assertSame(map.computeIfAbsent(KEYS[1], (k) -> EXTRA_VALUE), expected, description);
+        assertSame(map.get(KEYS[1]), expected, description);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.computeIfAbsent(EXTRA_KEY, (k) -> EXTRA_VALUE), EXTRA_VALUE);
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testComputeIfPresentNulls(String description, Map map) {
+        assertTrue(map.containsKey(null));
+        assertNull(map.get(null));
+        assertSame(map.computeIfPresent(null, (k, v) -> {
+            fail();
+            return EXTRA_VALUE;
+        }), null, description);
+        assertTrue(map.containsKey(null));
+        assertSame(map.get(null), null, description);
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testComputeIfPresent(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object value = map.get(KEYS[1]);
+        assertTrue(null == value || value == VALUES[1], description + String.valueOf(value));
+        Object expected = (null == value) ? null : EXTRA_VALUE;
+        assertSame(map.computeIfPresent(KEYS[1], (k, v) -> {
+            assertSame(v, value);
+            return EXTRA_VALUE;
+        }), expected, description);
+        assertSame(map.get(KEYS[1]), expected, description);
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.computeIfPresent(EXTRA_KEY, (k, v) -> {
+            fail();
+            return EXTRA_VALUE;
+        }), null);
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), null);
+    }
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testComputeNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.compute(null, (k, v) -> {
+            assertSame(k, null);
+            assertNull(v);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE, description);
+        assertTrue(map.containsKey(null));
+        assertSame(map.get(null), EXTRA_VALUE, description);
+        assertSame(map.remove(null), EXTRA_VALUE, "removed value not expected");
+        assertFalse(map.containsKey(null), "null key present");
+        assertSame(map.compute(null, (k, v) -> {
+            assertSame(k, null);
+            assertNull(v);
+            return null;
+        }), null, description);
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testCompute(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object value = map.get(KEYS[1]);
+        assertTrue(null == value || value == VALUES[1], description + String.valueOf(value));
+        assertSame(map.compute(KEYS[1], (k, v) -> {
+            assertSame(k, KEYS[1]);
+            assertSame(v, value);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE, description);
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE, description);
+        assertNull(map.compute(KEYS[1], (k, v) -> {
+            assertSame(v, EXTRA_VALUE);
+            return null;
+        }), description);
+        assertFalse(map.containsKey(KEYS[1]));
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.compute(EXTRA_KEY, (k, v) -> {
+            assertNull(v);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE);
+        assertTrue(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+
+    @Test(dataProvider = "R/W Nulls Map")
+    public void testMergeNulls(String description, Map map) {
+        assertTrue(map.containsKey(null), "null key absent");
+        assertNull(map.get(null), "value not null");
+        assertSame(map.merge(null, EXTRA_VALUE, (v, vv) -> {
+            assertNull(v);
+            assertSame(vv, EXTRA_VALUE);
+            return vv;
+        }), EXTRA_VALUE, description);
+        assertTrue(map.containsKey(null));
+        assertSame(map.get(null), EXTRA_VALUE, description);
+    }
+
+    @Test(dataProvider = "R/W Map")
+    public void testMerge(String description, Map map) {
+        assertTrue(map.containsKey(KEYS[1]));
+        Object value = map.get(KEYS[1]);
+        assertTrue(null == value || value == VALUES[1], description + String.valueOf(value));
+        assertSame(map.merge(KEYS[1], EXTRA_VALUE, (v, vv) -> {
+            assertSame(v, value);
+            assertSame(vv, EXTRA_VALUE);
+            return vv;
+        }), EXTRA_VALUE, description);
+        assertSame(map.get(KEYS[1]), EXTRA_VALUE, description);
+        assertNull(map.merge(KEYS[1], EXTRA_VALUE, (v, vv) -> {
+            assertSame(v, EXTRA_VALUE);
+            assertSame(vv, EXTRA_VALUE);
+            return null;
+        }), description);
+        assertFalse(map.containsKey(KEYS[1]));
+
+        assertFalse(map.containsKey(EXTRA_KEY));
+        assertSame(map.merge(EXTRA_KEY, EXTRA_VALUE, (v, vv) -> {
+            assertNull(v);
+            assertSame(vv, EXTRA_VALUE);
+            return EXTRA_VALUE;
+        }), EXTRA_VALUE);
+        assertTrue(map.containsKey(EXTRA_KEY));
+        assertSame(map.get(EXTRA_KEY), EXTRA_VALUE);
+    }
+
+    enum IntegerEnum {
+
+        e0, e1, e2, e3, e4, e5, e6, e7, e8, e9,
+        e10, e11, e12, e13, e14, e15, e16, e17, e18, e19,
+        e20, e21, e22, e23, e24, e25, e26, e27, e28, e29,
+        e30, e31, e32, e33, e34, e35, e36, e37, e38, e39,
+        e40, e41, e42, e43, e44, e45, e46, e47, e48, e49,
+        e50, e51, e52, e53, e54, e55, e56, e57, e58, e59,
+        e60, e61, e62, e63, e64, e65, e66, e67, e68, e69,
+        e70, e71, e72, e73, e74, e75, e76, e77, e78, e79,
+        e80, e81, e82, e83, e84, e85, e86, e87, e88, e89,
+        e90, e91, e92, e93, e94, e95, e96, e97, e98, e99,
+        EXTRA_KEY;
+        public static final int SIZE = values().length;
+    };
+    private static final int TEST_SIZE = IntegerEnum.SIZE - 1;
+    /**
+     * Realized keys ensure that there is always a hard ref to all test objects.
+     */
+    private static final IntegerEnum[] KEYS = new IntegerEnum[TEST_SIZE];
+    /**
+     * Realized values ensure that there is always a hard ref to all test
+     * objects.
+     */
+    private static final String[] VALUES = new String[TEST_SIZE];
+
+    static {
+        IntegerEnum[] keys = IntegerEnum.values();
+        for (int each = 0; each < TEST_SIZE; each++) {
+            KEYS[each] = keys[each];
+            VALUES[each] = String.valueOf(each);
+        }
+    }
+    private static final IntegerEnum EXTRA_KEY = IntegerEnum.EXTRA_KEY;
+    private static final String EXTRA_VALUE = String.valueOf(TEST_SIZE);
+
+    @DataProvider(name = "Map", parallel = true)
+    public static Iterator allNullsMapProvider() {
+        return makeAllMaps().iterator();
+    }
+
+    @DataProvider(name = "Nulls Map", parallel = true)
+    public static Iterator allMapProvider() {
+        return makeRWMaps(true).iterator();
+    }
+
+    @DataProvider(name = "R/W Map", parallel = true)
+    public static Iterator rwMapProvider() {
+        return makeRWMapsNoNulls().iterator();
+    }
+
+    @DataProvider(name = "R/W Nulls Map", parallel = true)
+    public static Iterator rwNullsMapProvider() {
+        return makeRWMaps(true).iterator();
+    }
+
+    private static Collection makeAllMapsNoNulls() {
+        Collection all = new ArrayList<>();
+
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+        all.addAll(makeROMaps(false));
+
+        return all;
+    }
+
+    private static Collection makeRWMapsNoNulls() {
+        Collection all = new ArrayList<>();
+
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+
+        return all;
+    }
+
+    private static Collection makeAllMaps() {
+        Collection all = new ArrayList<>();
+
+        all.addAll(makeROMaps(false));
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+        all.addAll(makeRWMaps(true));
+        all.addAll(makeROMaps(true));
+
+        return all;
+    }
+
+    private static Collection makeAllRWMaps() {
+        Collection all = new ArrayList<>();
+
+        all.addAll(makeRWMaps(false));
+        all.addAll(makeRWNoNullsMaps());
+        all.addAll(makeRWMaps(true));
+
+        return all;
+    }
+
+    private static Collection makeRWMaps(boolean nulls) {
+        return Arrays.asList(
+            new Object[]{"HashMap", makeMap(HashMap::new, nulls)},
+            new Object[]{"IdentityHashMap", makeMap(IdentityHashMap::new, nulls)},
+            new Object[]{"LinkedHashMap", makeMap(LinkedHashMap::new, nulls)},
+            new Object[]{"WeakHashMap", makeMap(WeakHashMap::new, nulls)},
+            new Object[]{"Collections.checkedMap(HashMap)", Collections.checkedMap(makeMap(HashMap::new, nulls), IntegerEnum.class, String.class)},
+            new Object[]{"Collections.synchronizedMap(HashMap)", Collections.synchronizedMap(makeMap(HashMap::new, nulls))},
+            new Object[]{"ExtendsAbstractMap", makeMap(ExtendsAbstractMap::new, nulls)});
+    }
+
+    private static Collection makeRWNoNullsMaps() {
+        return Arrays.asList(
+            // null hostile
+            new Object[]{"EnumMap", makeMap(() -> new EnumMap(IntegerEnum.class), false)},
+            new Object[]{"Hashtable", makeMap(Hashtable::new, false)},
+            new Object[]{"TreeMap", makeMap(TreeMap::new, false)},
+            new Object[]{"ConcurrentHashMap", makeMap(ConcurrentHashMap::new, false)},
+            new Object[]{"ConcurrentSkipListMap", makeMap(ConcurrentSkipListMap::new, false)},
+            new Object[]{"Collections.checkedMap(ConcurrentHashMap)", Collections.checkedMap(makeMap(ConcurrentHashMap::new, false), IntegerEnum.class, String.class)},
+            new Object[]{"Collections.synchronizedMap(EnumMap)", Collections.synchronizedMap(makeMap(() -> new EnumMap(IntegerEnum.class), false))},
+            new Object[]{"ImplementsConcurrentMap", makeMap(ImplementsConcurrentMap::new, false)});
+    }
+
+    private static Collection makeROMaps(boolean nulls) {
+        return Arrays.asList(new Object[][]{
+            new Object[]{"Collections.unmodifiableMap(HashMap)", Collections.unmodifiableMap(makeMap(HashMap::new, nulls))}
+        });
+    }
+
+    private static Map makeMap(Supplier> supplier, boolean nulls) {
+        Map result = supplier.get();
+
+        for (int each = 0; each < TEST_SIZE; each++) {
+            if (nulls) {
+                result.put((each == 0) ? null : KEYS[each], null);
+            } else {
+                result.put(KEYS[each], VALUES[each]);
+            }
+        }
+
+        return result;
+    }
+
+    public interface Thrower {
+
+        public void run() throws T;
+    }
+
+    public static  void assertThrows(Thrower thrower, Class throwable) {
+        assertThrows(thrower, throwable, null);
+    }
+
+    public static  void assertThrows(Thrower thrower, Class throwable, String message) {
+        Throwable result;
+        try {
+            thrower.run();
+            result = null;
+        } catch (Throwable caught) {
+            result = caught;
+        }
+
+        assertInstance(result, throwable,
+            (null != message)
+            ? message
+            : "Failed to throw " + throwable.getCanonicalName());
+    }
+
+    public static  void assertInstance(T actual, Class expected) {
+        assertInstance(expected.isInstance(actual), null);
+    }
+
+    public static  void assertInstance(T actual, Class expected, String message) {
+        assertTrue(expected.isInstance(actual), message);
+    }
 
     /**
-     * Number of elements per map.
+     * A simple mutable map implementation that provides only default
+     * implementations of all methods. ie. none of the Map interface default
+     * methods have overridden implementations.
+     *
+     * @param  Type of keys
+     * @param  Type of values
      */
-    private static final int TEST_SIZE = 5000;
+    public static class ExtendsAbstractMap, K, V> extends AbstractMap {
 
-    private static void realMain(String[] args) throws Throwable {
-        Map[] maps = (Map[]) new Map[]{
-                    new HashMap<>(),
-                    new Hashtable<>(),
-                    new IdentityHashMap<>(),
-                    new LinkedHashMap<>(),
-                    new TreeMap<>(),
-                    new WeakHashMap<>(),
-                    new ConcurrentHashMap<>(),
-                    new ConcurrentSkipListMap<>()
-                };
+        protected final M map;
 
-        // for each map type.
-        for (Map map : maps) {
-             try {
-                testMap(map);
-             } catch(Exception all) {
-                unexpected("Failed for " + map.getClass().getName(), all);
-             }
+        public ExtendsAbstractMap() { this( (M) new HashMap()); }
+
+        protected ExtendsAbstractMap(M map) { this.map = map; }
+
+        public Set> entrySet() {
+            return new AbstractSet>() {
+                public int size() {
+                    return map.size();
+                }
+
+                public Iterator> iterator() {
+                    final Iterator> source = map.entrySet().iterator();
+                    return new Iterator>() {
+                       public boolean hasNext() { return source.hasNext(); }
+                       public Map.Entry next() { return source.next(); }
+                       public void remove() { source.remove(); }
+                    };
+                }
+
+                public boolean add(Map.Entry e) {
+                    return map.entrySet().add(e);
+                }
+            };
+        }
+
+        public V put(K key, V value) {
+            return map.put(key, value);
         }
     }
 
-    private static final Integer[] KEYS = new Integer[TEST_SIZE];
+    /**
+     * A simple mutable concurrent map implementation that provides only default
+     * implementations of all methods. ie. none of the ConcurrentMap interface
+     * default methods have overridden implementations.
+     *
+     * @param  Type of keys
+     * @param  Type of values
+     */
+    public static class ImplementsConcurrentMap extends ExtendsAbstractMap, K, V> implements ConcurrentMap {
+        public ImplementsConcurrentMap() { super(new ConcurrentHashMap()); }
 
-    private static final Long[] VALUES = new Long[TEST_SIZE];
+        // ConcurrentMap reabstracts these methods
 
-    static {
-        for (int each = 0; each < TEST_SIZE; each++) {
-            KEYS[each]   = Integer.valueOf(each);
-            VALUES[each] = Long.valueOf(each + TEST_SIZE);
-        }
-    }
+        public V replace(K k, V v) { return map.replace(k, v); };
 
+        public boolean replace(K k, V v, V vv) { return map.replace(k, v, vv); };
 
-    private static void testMap(Map map) {
-        System.out.println("Testing " + map.getClass());
-        System.out.flush();
+        public boolean remove(Object k, Object v) { return map.remove(k, v); }
 
-        // Fill the map
-        for (int each = 0; each < TEST_SIZE; each++) {
-            map.put(KEYS[each], VALUES[each]);
-        }
-
-        // check the keys
-        Object[] keys = map.keySet().toArray();
-        Arrays.sort(keys);
-
-        for(int each = 0; each < TEST_SIZE; each++) {
-            check( "unexpected key", keys[each] == KEYS[each]);
-        }
-
-        // check the values
-        Object[] values = map.values().toArray();
-        Arrays.sort(values);
-
-        for(int each = 0; each < TEST_SIZE; each++) {
-            check( "unexpected value", values[each] == VALUES[each]);
-        }
-
-        // check the entries
-        Map.Entry[] entries = map.entrySet().toArray(new Map.Entry[TEST_SIZE]);
-        Arrays.sort( entries,new Comparator>() {
-                public int compare(Map.Entry o1, Map.Entry o2) {
-                        return o1.getKey().compareTo(o2.getKey());
-                }});
-
-        for(int each = 0; each < TEST_SIZE; each++) {
-            check( "unexpected entry", entries[each].getKey() == KEYS[each] && entries[each].getValue() == VALUES[each]);
-        }
-    }
-
-    //--------------------- Infrastructure ---------------------------
-    static volatile int passed = 0, failed = 0;
-
-    static void pass() {
-        passed++;
-    }
-
-    static void fail() {
-        failed++;
-        (new Error("Failure")).printStackTrace(System.err);
-    }
-
-    static void fail(String msg) {
-        failed++;
-        (new Error("Failure: " + msg)).printStackTrace(System.err);
-    }
-
-    static void abort() {
-        fail();
-        System.exit(1);
-    }
-
-    static void abort(String msg) {
-        fail(msg);
-        System.exit(1);
-    }
-
-    static void unexpected(String msg, Throwable t) {
-        System.err.println("Unexpected: " + msg);
-        unexpected(t);
-    }
-
-    static void unexpected(Throwable t) {
-        failed++;
-        t.printStackTrace(System.err);
-    }
-
-    static void check(boolean cond) {
-        if (cond) {
-            pass();
-        } else {
-            fail();
-        }
-    }
-
-    static void check(String desc, boolean cond) {
-        if (cond) {
-            pass();
-        } else {
-            fail(desc);
-        }
-    }
-
-    static void equal(Object x, Object y) {
-        if (Objects.equals(x, y)) {
-            pass();
-        } else {
-            fail(x + " not equal to " + y);
-        }
-    }
-
-    public static void main(String[] args) throws Throwable {
-        Thread.currentThread().setName(ToArray.class.getName());
-//        Thread.currentThread().setPriority(Thread.MAX_PRIORITY);
-        try {
-            realMain(args);
-        } catch (Throwable t) {
-            unexpected(t);
-        }
-
-        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
-        if (failed > 0) {
-            throw new Error("Some tests failed");
-        }
+        public V putIfAbsent(K k, V v) { return map.putIfAbsent(k, v); }
     }
 }