1 /*
   2  * Copyright (c) 2017, 2017, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  */
  23 
  24 
  25 package jdk.internal.vm.compiler.collections;
  26 
  27 /**
  28  * Unmodifiable memory efficient map data structure.
  29  *
  30  * @since 1.0
  31  */
  32 public interface UnmodifiableEconomicMap<K, V> {
  33 
  34     /**
  35      * Returns the value to which {@code key} is mapped, or {@code null} if this map contains no
  36      * mapping for {@code key}.
  37      *
  38      * @since 1.0
  39      */
  40     V get(K key);
  41 
  42     /**
  43      * Returns the value to which {@code key} is mapped, or {@code defaultValue} if this map
  44      * contains no mapping for {@code key}.
  45      *
  46      * @since 1.0
  47      */
  48     default V get(K key, V defaultValue) {
  49         V v = get(key);
  50         if (v == null) {
  51             return defaultValue;
  52         }
  53         return v;
  54     }
  55 
  56     /**
  57      * Returns {@code true} if this map contains a mapping for {@code key}.
  58      *
  59      * @since 1.0
  60      */
  61     boolean containsKey(K key);
  62 
  63     /**
  64      * Returns the number of key-value mappings in this map.
  65      *
  66      * @since 1.0
  67      */
  68     int size();
  69 
  70     /**
  71      * Returns {@code true} if this map contains no key-value mappings.
  72      *
  73      * @since 1.0
  74      */
  75     boolean isEmpty();
  76 
  77     /**
  78      * Returns a {@link Iterable} view of the values contained in this map.
  79      *
  80      * @since 1.0
  81      */
  82     Iterable<V> getValues();
  83 
  84     /**
  85      * Returns a {@link Iterable} view of the keys contained in this map.
  86      *
  87      * @since 1.0
  88      */
  89     Iterable<K> getKeys();
  90 
  91     /**
  92      * Returns a {@link UnmodifiableMapCursor} view of the mappings contained in this map.
  93      *
  94      * @since 1.0
  95      */
  96     UnmodifiableMapCursor<K, V> getEntries();
  97 }