1 /** 2 * Copyright (C) 2008 Google Inc. 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.inject.internal; 18 19 import static com.google.common.base.Preconditions.checkArgument; 20 import static com.google.common.base.Preconditions.checkNotNull; 21 import static com.google.common.base.Preconditions.checkState; 22 23 import com.google.common.base.Objects; 24 import com.google.common.collect.ImmutableList; 25 import com.google.common.collect.ImmutableMap; 26 import com.google.common.collect.Lists; 27 import com.google.common.collect.Maps; 28 import com.google.inject.Binder; 29 import com.google.inject.Injector; 30 import com.google.inject.Key; 31 import com.google.inject.PrivateBinder; 32 import com.google.inject.spi.Element; 33 import com.google.inject.spi.ElementVisitor; 34 import com.google.inject.spi.PrivateElements; 35 36 import java.util.List; 37 import java.util.Map; 38 import java.util.Set; 39 40 /** 41 * @author jessewilson (at) google.com (Jesse Wilson) 42 */ 43 public final class PrivateElementsImpl implements PrivateElements { 44 45 /* 46 * This class acts as both a value object and as a builder. When getElements() is called, an 47 * immutable collection of elements is constructed and the original mutable list is nulled out. 48 * Similarly, the exposed keys are made immutable on access. 49 */ 50 51 private final Object source; 52 53 private List<Element> elementsMutable = Lists.newArrayList(); 54 private List<ExposureBuilder<?>> exposureBuilders = Lists.newArrayList(); 55 56 /** lazily instantiated */ 57 private ImmutableList<Element> elements; 58 59 /** lazily instantiated */ 60 private ImmutableMap<Key<?>, Object> exposedKeysToSources; 61 private Injector injector; 62 63 public PrivateElementsImpl(Object source) { 64 this.source = checkNotNull(source, "source"); 65 } 66 67 public Object getSource() { 68 return source; 69 } 70 71 public List<Element> getElements() { 72 if (elements == null) { 73 elements = ImmutableList.copyOf(elementsMutable); 74 elementsMutable = null; 75 } 76 77 return elements; 78 } 79 80 public Injector getInjector() { 81 return injector; 82 } 83 84 public void initInjector(Injector injector) { 85 checkState(this.injector == null, "injector already initialized"); 86 this.injector = checkNotNull(injector, "injector"); 87 } 88 89 public Set<Key<?>> getExposedKeys() { 90 if (exposedKeysToSources == null) { 91 Map<Key<?>, Object> exposedKeysToSourcesMutable = Maps.newLinkedHashMap(); 92 for (ExposureBuilder<?> exposureBuilder : exposureBuilders) { 93 exposedKeysToSourcesMutable.put(exposureBuilder.getKey(), exposureBuilder.getSource()); 94 } 95 exposedKeysToSources = ImmutableMap.copyOf(exposedKeysToSourcesMutable); 96 exposureBuilders = null; 97 } 98 99 return exposedKeysToSources.keySet(); 100 } 101 102 public <T> T acceptVisitor(ElementVisitor<T> visitor) { 103 return visitor.visit(this); 104 } 105 106 public List<Element> getElementsMutable() { 107 return elementsMutable; 108 } 109 110 public void addExposureBuilder(ExposureBuilder<?> exposureBuilder) { 111 exposureBuilders.add(exposureBuilder); 112 } 113 114 public void applyTo(Binder binder) { 115 PrivateBinder privateBinder = binder.withSource(source).newPrivateBinder(); 116 117 for (Element element : getElements()) { 118 element.applyTo(privateBinder); 119 } 120 121 getExposedKeys(); // ensure exposedKeysToSources is populated 122 for (Map.Entry<Key<?>, Object> entry : exposedKeysToSources.entrySet()) { 123 privateBinder.withSource(entry.getValue()).expose(entry.getKey()); 124 } 125 } 126 127 public Object getExposedSource(Key<?> key) { 128 getExposedKeys(); // ensure exposedKeysToSources is populated 129 Object source = exposedKeysToSources.get(key); 130 checkArgument(source != null, "%s not exposed by %s.", key, this); 131 return source; 132 } 133 134 @Override public String toString() { 135 return Objects.toStringHelper(PrivateElements.class) 136 .add("exposedKeys", getExposedKeys()) 137 .add("source", getSource()) 138 .toString(); 139 } 140 } 141
