com.google.common.collect.RegularImmutableMap Maven / Gradle / Ivy
/*
* Copyright (C) 2008 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.common.collect;
import com.google.common.annotations.GwtCompatible;
import com.google.common.collect.ImmutableSet.ArrayImmutableSet;
import com.google.common.collect.ImmutableSet.TransformedImmutableSet;
/**
* Implementation of {@link ImmutableMap} with two or more entries.
*
* @author Jesse Wilson
* @author Kevin Bourrillion
*/
@GwtCompatible(serializable = true, emulated = true)
final class RegularImmutableMap extends ImmutableMap {
private final transient Entry[] entries; // entries in insertion order
private final transient Object[] table; // alternating keys and values
// 'and' with an int then shift to get a table index
private final transient int mask;
private final transient int keySetHashCode;
RegularImmutableMap(Entry... immutableEntries) {
// each of our 6 callers carefully put only Entrys into the array!
@SuppressWarnings("unchecked")
Entry[] tmp = (Entry[]) immutableEntries;
this.entries = tmp;
int tableSize = Hashing.chooseTableSize(immutableEntries.length);
table = new Object[tableSize * 2];
mask = tableSize - 1;
int keySetHashCodeMutable = 0;
for (Entry entry : this.entries) {
K key = entry.getKey();
int keyHashCode = key.hashCode();
for (int i = Hashing.smear(keyHashCode); true; i++) {
int index = (i & mask) * 2;
Object existing = table[index];
if (existing == null) {
V value = entry.getValue();
table[index] = key;
table[index + 1] = value;
keySetHashCodeMutable += keyHashCode;
break;
} else if (existing.equals(key)) {
throw new IllegalArgumentException("duplicate key: " + key);
}
}
}
keySetHashCode = keySetHashCodeMutable;
}
@Override public V get(Object key) {
if (key == null) {
return null;
}
for (int i = Hashing.smear(key.hashCode()); true; i++) {
int index = (i & mask) * 2;
Object candidate = table[index];
if (candidate == null) {
return null;
}
if (candidate.equals(key)) {
// we're careful to store only V's at odd indices
@SuppressWarnings("unchecked")
V value = (V) table[index + 1];
return value;
}
}
}
public int size() {
return entries.length;
}
@Override public boolean isEmpty() {
return false;
}
@Override public boolean containsValue(Object value) {
if (value == null) {
return false;
}
for (Entry entry : entries) {
if (entry.getValue().equals(value)) {
return true;
}
}
return false;
}
// TODO: Serialization of the map views should serialize the map, and
// deserialization should call entrySet(), keySet(), or values() on the
// deserialized map. The views are serializable since the Immutable* classes
// are.
private transient ImmutableSet> entrySet;
@Override public ImmutableSet> entrySet() {
ImmutableSet> es = entrySet;
return (es == null) ? (entrySet = new EntrySet(this)) : es;
}
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
private static class EntrySet extends ArrayImmutableSet> {
final transient RegularImmutableMap map;
EntrySet(RegularImmutableMap map) {
super(map.entries);
this.map = map;
}
@Override public boolean contains(Object target) {
if (target instanceof Entry) {
Entry entry = (Entry) target;
V mappedValue = map.get(entry.getKey());
return mappedValue != null && mappedValue.equals(entry.getValue());
}
return false;
}
}
private transient ImmutableSet keySet;
@Override public ImmutableSet keySet() {
ImmutableSet ks = keySet;
return (ks == null) ? (keySet = new KeySet(this)) : ks;
}
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
private static class KeySet
extends TransformedImmutableSet, K> {
final RegularImmutableMap map;
KeySet(RegularImmutableMap map) {
super(map.entries, map.keySetHashCode);
this.map = map;
}
@Override K transform(Entry element) {
return element.getKey();
}
@Override public boolean contains(Object target) {
return map.containsKey(target);
}
}
private transient ImmutableCollection values;
@Override public ImmutableCollection values() {
ImmutableCollection v = values;
return (v == null) ? (values = new Values(this)) : v;
}
@SuppressWarnings("serial") // uses writeReplace(), not default serialization
private static class Values extends ImmutableCollection {
final RegularImmutableMap map;
Values(RegularImmutableMap map) {
this.map = map;
}
public int size() {
return map.entries.length;
}
@Override public UnmodifiableIterator iterator() {
return new AbstractIterator() {
int index = 0;
@Override protected V computeNext() {
return (index < map.entries.length)
? map.entries[index++].getValue()
: endOfData();
}
};
}
@Override public boolean contains(Object target) {
return map.containsValue(target);
}
}
@Override public String toString() {
StringBuilder result = new StringBuilder(size() * 16).append('{');
Collections2.standardJoiner.appendTo(result, entries);
return result.append('}').toString();
}
// This class is never actually serialized directly, but we have to make the
// warning go away (and suppressing would suppress for all nested classes too)
private static final long serialVersionUID = 0;
}