1 /*
   2  * Copyright (c) 2017, 2018, 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  */
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  41 package jdk.internal.vm.compiler.collections;
  42 
  43 /**
  44  * Unmodifiable memory efficient map data structure.
  45  *
  46  * @since 1.0
  47  */
  48 public interface UnmodifiableEconomicMap<K, V> {
  49 
  50     /**
  51      * Returns the value to which {@code key} is mapped, or {@code null} if this map contains no
  52      * mapping for {@code key}.
  53      *
  54      * @since 1.0
  55      */
  56     V get(K key);
  57 
  58     /**
  59      * Returns the value to which {@code key} is mapped, or {@code defaultValue} if this map
  60      * contains no mapping for {@code key}.
  61      *
  62      * @since 1.0
  63      */
  64     default V get(K key, V defaultValue) {
  65         V v = get(key);
  66         if (v == null) {
  67             return defaultValue;
  68         }
  69         return v;
  70     }
  71 
  72     /**
  73      * Returns {@code true} if this map contains a mapping for {@code key}.
  74      *
  75      * @since 1.0
  76      */
  77     boolean containsKey(K key);
  78 
  79     /**
  80      * Returns the number of key-value mappings in this map.
  81      *
  82      * @since 1.0
  83      */
  84     int size();
  85 
  86     /**
  87      * Returns {@code true} if this map contains no key-value mappings.
  88      *
  89      * @since 1.0
  90      */
  91     boolean isEmpty();
  92 
  93     /**
  94      * Returns a {@link Iterable} view of the values contained in this map.
  95      *
  96      * @since 1.0
  97      */
  98     Iterable<V> getValues();
  99 
 100     /**
 101      * Returns a {@link Iterable} view of the keys contained in this map.
 102      *
 103      * @since 1.0
 104      */
 105     Iterable<K> getKeys();
 106 
 107     /**
 108      * Returns a {@link UnmodifiableMapCursor} view of the mappings contained in this map.
 109      *
 110      * @since 1.0
 111      */
 112     UnmodifiableMapCursor<K, V> getEntries();
 113 }