1 /* 2 * Copyright (C) 2012 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.reflect; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import com.google.common.annotations.Beta; 22 import com.google.common.base.Function; 23 import com.google.common.collect.ForwardingMap; 24 import com.google.common.collect.ForwardingMapEntry; 25 import com.google.common.collect.ForwardingSet; 26 import com.google.common.collect.Iterators; 27 import com.google.common.collect.Maps; 28 29 import java.util.Iterator; 30 import java.util.Map; 31 import java.util.Set; 32 33 import javax.annotation.Nullable; 34 35 /** 36 * A mutable type-to-instance map. 37 * See also {@link ImmutableTypeToInstanceMap}. 38 * 39 * @author Ben Yu 40 * @since 13.0 41 */ 42 @Beta 43 public final class MutableTypeToInstanceMap<B> extends ForwardingMap<TypeToken<? extends B>, B> 44 implements TypeToInstanceMap<B> { 45 46 private final Map<TypeToken<? extends B>, B> backingMap = Maps.newHashMap(); 47 48 @Nullable 49 @Override 50 public <T extends B> T getInstance(Class<T> type) { 51 return trustedGet(TypeToken.of(type)); 52 } 53 54 @Nullable 55 @Override 56 public <T extends B> T putInstance(Class<T> type, @Nullable T value) { 57 return trustedPut(TypeToken.of(type), value); 58 } 59 60 @Nullable 61 @Override 62 public <T extends B> T getInstance(TypeToken<T> type) { 63 return trustedGet(type.rejectTypeVariables()); 64 } 65 66 @Nullable 67 @Override 68 public <T extends B> T putInstance(TypeToken<T> type, @Nullable T value) { 69 return trustedPut(type.rejectTypeVariables(), value); 70 } 71 72 /** Not supported. Use {@link #putInstance} instead. */ 73 @Override public B put(TypeToken<? extends B> key, B value) { 74 throw new UnsupportedOperationException("Please use putInstance() instead."); 75 } 76 77 /** Not supported. Use {@link #putInstance} instead. */ 78 @Override public void putAll(Map<? extends TypeToken<? extends B>, ? extends B> map) { 79 throw new UnsupportedOperationException("Please use putInstance() instead."); 80 } 81 82 @Override public Set<Entry<TypeToken<? extends B>, B>> entrySet() { 83 return UnmodifiableEntry.transformEntries(super.entrySet()); 84 } 85 86 @Override protected Map<TypeToken<? extends B>, B> delegate() { 87 return backingMap; 88 } 89 90 @SuppressWarnings("unchecked") // value could not get in if not a T 91 @Nullable 92 private <T extends B> T trustedPut(TypeToken<T> type, @Nullable T value) { 93 return (T) backingMap.put(type, value); 94 } 95 96 @SuppressWarnings("unchecked") // value could not get in if not a T 97 @Nullable 98 private <T extends B> T trustedGet(TypeToken<T> type) { 99 return (T) backingMap.get(type); 100 } 101 102 private static final class UnmodifiableEntry<K, V> extends ForwardingMapEntry<K, V> { 103 104 private final Entry<K, V> delegate; 105 106 static <K, V> Set<Entry<K, V>> transformEntries(final Set<Entry<K, V>> entries) { 107 return new ForwardingSet<Map.Entry<K, V>>() { 108 @Override protected Set<Entry<K, V>> delegate() { 109 return entries; 110 } 111 @Override public Iterator<Entry<K, V>> iterator() { 112 return UnmodifiableEntry.transformEntries(super.iterator()); 113 } 114 @Override public Object[] toArray() { 115 return standardToArray(); 116 } 117 @Override public <T> T[] toArray(T[] array) { 118 return standardToArray(array); 119 } 120 }; 121 } 122 123 private static <K, V> Iterator<Entry<K, V>> transformEntries(Iterator<Entry<K, V>> entries) { 124 return Iterators.transform(entries, new Function<Entry<K, V>, Entry<K, V>>() { 125 @Override public Entry<K, V> apply(Entry<K, V> entry) { 126 return new UnmodifiableEntry<K, V>(entry); 127 } 128 }); 129 } 130 131 private UnmodifiableEntry(java.util.Map.Entry<K, V> delegate) { 132 this.delegate = checkNotNull(delegate); 133 } 134 135 @Override protected Entry<K, V> delegate() { 136 return delegate; 137 } 138 139 @Override public V setValue(V value) { 140 throw new UnsupportedOperationException(); 141 } 142 } 143 } 144
