1 /* 2 * Copyright (c) 2014, 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 package org.graalvm.compiler.core.common; 24 25 import static org.graalvm.compiler.core.common.CollectionsFactory.Mode.STANDARD; 26 27 import java.util.Collection; 28 import java.util.HashMap; 29 import java.util.HashSet; 30 import java.util.IdentityHashMap; 31 import java.util.LinkedHashMap; 32 import java.util.LinkedHashSet; 33 import java.util.Map; 34 import java.util.Set; 35 36 /** 37 * Factory for creating collection objects used during compilation. 38 */ 39 public class CollectionsFactory { 40 41 private static final ThreadLocal<Mode> tl = new ThreadLocal<>(); 42 43 public static class ModeScope implements AutoCloseable { 44 private final Mode previousMode; 45 46 public ModeScope(Mode previousMode) { 47 this.previousMode = previousMode; 48 } 49 50 @Override 51 public void close() { 52 tl.set(previousMode); 53 } 54 } 55 56 /** 57 * Constants denoting what type of collections are {@link CollectionsFactory#getMode() 58 * currently} returned by the factory. 59 */ 60 public enum Mode { 61 /** 62 * Denotes standard collections such as {@link HashSet} and {@link HashMap}. 63 */ 64 STANDARD, 65 66 /** 67 * Denotes collections that have a deterministic iteration order over their keys/entries. 68 */ 69 DETERMINISTIC_ITERATION_ORDER; 70 } 71 72 /** 73 * Gets the current mode determining the type of collection objects created by this factory. 74 */ 75 public static Mode getMode() { 76 Mode mode = tl.get(); 77 return mode == null ? Mode.STANDARD : mode; 78 } 79 80 /** 81 * Updates the mode for the current thread. 82 * 83 * @return an object which when {@linkplain ModeScope#close() closed} will revert the mode of 84 * the current thread to the state before calling this method 85 */ 86 public static ModeScope changeMode(Mode mode) { 87 Mode previousMode = tl.get(); 88 tl.set(mode); 89 return new ModeScope(previousMode); 90 } 91 92 public static <K, V> HashMap<K, V> newMap() { 93 return getMode() == STANDARD ? new HashMap<>() : new LinkedHashMap<>(); 94 } 95 96 public static <K, V> HashMap<K, V> newMap(Map<K, V> m) { 97 return getMode() == STANDARD ? new HashMap<>(m) : new LinkedHashMap<>(m); 98 } 99 100 public static <K, V> HashMap<K, V> newMap(int initialCapacity) { 101 return getMode() == STANDARD ? new HashMap<>(initialCapacity) : new LinkedHashMap<>(initialCapacity); 102 } 103 104 public static <K, V> Map<K, V> newIdentityMap() { 105 return getMode() == STANDARD ? new IdentityHashMap<>() : new LinkedIdentityHashMap<>(); 106 } 107 108 public static <K, V> Map<K, V> newIdentityMap(int expectedMaxSize) { 109 return getMode() == STANDARD ? new IdentityHashMap<>(expectedMaxSize) : new LinkedIdentityHashMap<>(); 110 } 111 112 public static <K, V> Map<K, V> newIdentityMap(Map<K, V> m) { 113 return getMode() == STANDARD ? new IdentityHashMap<>(m) : new LinkedIdentityHashMap<>(m); 114 } 115 116 /** 117 * Creates a set. If the current thread is {@linkplain CollectionsFactory#getMode() using} 118 * {@link Mode#DETERMINISTIC_ITERATION_ORDER} collections, the returned set will have an 119 * iteration order determined by the order in which elements are inserted in the set. 120 */ 121 public static <E> Set<E> newSet() { 122 return CollectionsFactory.getMode() == Mode.STANDARD ? new HashSet<>() : new LinkedHashSet<>(); 123 } 124 125 /** 126 * @see #newSet() 127 */ 128 public static <E> Set<E> newSet(Collection<? extends E> c) { 129 return CollectionsFactory.getMode() == Mode.STANDARD ? new HashSet<>(c) : new LinkedHashSet<>(c); 130 } 131 132 }