/* * Copyright (C) 2009 The Guava Authors * * 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 static com.google.common.base.Preconditions.checkNotNull; import java.io.Serializable; import java.util.Map; import javax.annotation.Nullable; import com.google.common.primitives.Primitives; /** * A class-to-instance map backed by an {@link ImmutableMap}. See also * {@link MutableClassToInstanceMap}. * * @author Kevin Bourrillion * @since 2.0 (imported from Google Collections Library) */ public final class ImmutableClassToInstanceMap extends ForwardingMap, B> implements ClassToInstanceMap, Serializable { /** * Returns a new builder. The generated builder is equivalent to the builder * created by the {@link Builder} constructor. */ public static Builder builder() { return new Builder(); } /** * A builder for creating immutable class-to-instance maps. Example: * *
	 * {
	 * 	@code
	 *
	 * 	static final ImmutableClassToInstanceMap HANDLERS = new ImmutableClassToInstanceMap.Builder()
	 * 			.put(FooHandler.class, new FooHandler()).put(BarHandler.class, new SubBarHandler())
	 * 			.put(Handler.class, new QuuxHandler()).build();
	 * }
	 * 
* *

* After invoking {@link #build()} it is still possible to add more entries and * build again. Thus each map generated by this builder will be a superset of * any map generated before it. * * @since 2.0 (imported from Google Collections Library) */ public static final class Builder { private final ImmutableMap.Builder, B> mapBuilder = ImmutableMap.builder(); /** * Associates {@code key} with {@code value} in the built map. Duplicate keys * are not allowed, and will cause {@link #build} to fail. */ public Builder put(Class key, T value) { mapBuilder.put(key, value); return this; } /** * Associates all of {@code map's} keys and values in the built map. Duplicate * keys are not allowed, and will cause {@link #build} to fail. * * @throws NullPointerException if any key or value in {@code map} is null * @throws ClassCastException if any value is not an instance of the type * specified by its key */ public Builder putAll(Map, ? extends T> map) { for (Entry, ? extends T> entry : map.entrySet()) { Class type = entry.getKey(); T value = entry.getValue(); mapBuilder.put(type, cast(type, value)); } return this; } private static T cast(Class type, B value) { return Primitives.wrap(type).cast(value); } /** * Returns a new immutable class-to-instance map containing the entries provided * to this builder. * * @throws IllegalArgumentException if duplicate keys were added */ public ImmutableClassToInstanceMap build() { return new ImmutableClassToInstanceMap(mapBuilder.build()); } } /** * Returns an immutable map containing the same entries as {@code map}. If * {@code map} somehow contains entries with duplicate keys (for example, if it * is a {@code SortedMap} whose comparator is not consistent with * equals), the results of this method are undefined. * *

* Note: Despite what the method name suggests, if {@code map} is an * {@code ImmutableClassToInstanceMap}, no copy will actually be performed. * * @throws NullPointerException if any key or value in {@code map} is null * @throws ClassCastException if any value is not an instance of the type * specified by its key */ public static ImmutableClassToInstanceMap copyOf( Map, ? extends S> map) { if (map instanceof ImmutableClassToInstanceMap) { @SuppressWarnings("unchecked") // covariant casts safe (unmodifiable) // Eclipse won't compile if we cast to the parameterized type. ImmutableClassToInstanceMap cast = (ImmutableClassToInstanceMap) map; return cast; } return new Builder().putAll(map).build(); } private final ImmutableMap, B> delegate; private ImmutableClassToInstanceMap(ImmutableMap, B> delegate) { this.delegate = delegate; } @Override protected Map, B> delegate() { return delegate; } @Override @SuppressWarnings("unchecked") // value could not get in if not a T @Nullable public T getInstance(Class type) { return (T) delegate.get(checkNotNull(type)); } /** * Guaranteed to throw an exception and leave the map unmodified. * * @throws UnsupportedOperationException always * @deprecated Unsupported operation. */ @Deprecated @Override public T putInstance(Class type, T value) { throw new UnsupportedOperationException(); } }