001/* 002 * Copyright (C) 2012 The Guava Authors 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package com.google.common.reflect; 018 019import com.google.common.annotations.Beta; 020import com.google.common.collect.ForwardingMap; 021import com.google.common.collect.Maps; 022 023import java.util.Map; 024 025import javax.annotation.Nullable; 026 027/** 028 * A mutable type-to-instance map. 029 * See also {@link ImmutableTypeToInstanceMap}. 030 * 031 * @author Ben Yu 032 * @since 13.0 033 */ 034@Beta 035public final class MutableTypeToInstanceMap<B> extends ForwardingMap<TypeToken<? extends B>, B> 036 implements TypeToInstanceMap<B> { 037 038 private final Map<TypeToken<? extends B>, B> backingMap = Maps.newHashMap(); 039 040 @Nullable 041 @Override 042 public <T extends B> T getInstance(Class<T> type) { 043 return trustedGet(TypeToken.of(type)); 044 } 045 046 @Nullable 047 @Override 048 public <T extends B> T putInstance(Class<T> type, @Nullable T value) { 049 return trustedPut(TypeToken.of(type), value); 050 } 051 052 @Nullable 053 @Override 054 public <T extends B> T getInstance(TypeToken<T> type) { 055 return trustedGet(type.rejectTypeVariables()); 056 } 057 058 @Nullable 059 @Override 060 public <T extends B> T putInstance(TypeToken<T> type, @Nullable T value) { 061 return trustedPut(type.rejectTypeVariables(), value); 062 } 063 064 /** Not supported. Use {@link #putInstance} instead. */ 065 @Override public B put(TypeToken<? extends B> key, B value) { 066 throw new UnsupportedOperationException("Please use putInstance() instead."); 067 } 068 069 /** Not supported. Use {@link #putInstance} instead. */ 070 @Override public void putAll(Map<? extends TypeToken<? extends B>, ? extends B> map) { 071 throw new UnsupportedOperationException("Please use putInstance() instead."); 072 } 073 074 @Override protected Map<TypeToken<? extends B>, B> delegate() { 075 return backingMap; 076 } 077 078 @SuppressWarnings("unchecked") // value could not get in if not a T 079 @Nullable 080 private <T extends B> T trustedPut(TypeToken<T> type, @Nullable T value) { 081 return (T) backingMap.put(type, value); 082 } 083 084 @SuppressWarnings("unchecked") // value could not get in if not a T 085 @Nullable 086 private <T extends B> T trustedGet(TypeToken<T> type) { 087 return (T) backingMap.get(type); 088 } 089}