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/*
* Copyright (C) 2016-2017 the original author or 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 io.github.pustike.inject;
import java.lang.annotation.Annotation;
import java.util.List;
import java.util.Objects;
import javax.inject.Named;
import javax.inject.Provider;
/**
* Binding key that contains an injection type and an optional qualifier annotation. It is also used to match the type
* and qualifier annotation at the point of injection.
* @param the type of the class specified in this key
*/
public final class BindingKey {
// the injection type
private final Class type;
// qualifier annotation
private final Annotation annotation;
// type of qualifier annotation
private final Class annotationType;
// indicates that this key matches to a provider of the type
private boolean providerKey;
// indicates that this key matches to a List of the type
private boolean multiBinding;
// hash code of this binding key, computed lazily using all specified parameters
private int hashCode;
/**
* Constructs a new Binding Key for the specified type, the qualifier annotation and annotation type.
* @param type the injection class
* @param annotation the qualifying annotation defined for the type
* @param annotationType the type of qualifier annotation defined for the type
*/
private BindingKey(Class type, Annotation annotation, Class annotationType) {
this.type = Objects.requireNonNull(type);
this.annotation = annotation;
this.annotationType = annotationType;
}
/**
* Constructs a new Binding Key for the specified type.
* @param type the injection class
* @param the type of of the class modeled by this key
* @return a new key with the specified type and no qualifying annotation
*/
public static BindingKey of(Class type) {
return new BindingKey<>(type, null, null);
}
/**
* Constructs a new Binding Key for the specified type and name.
* @param type the injection class
* @param named the qualifying name defined for the type
* @param the type of of the class modeled by this key
* @return a new key with the specified type and the named qualifier
*/
public static BindingKey of(Class type, String named) {
return new BindingKey<>(type, Names.named(named), null);
}
/**
* Constructs a new Binding Key for the specified type and the qualifier annotation.
* @param type the injection class
* @param annotation the qualifying annotation defined for the type
* @param the type of of the class modeled by this key
* @return a new key with the specified type and the qualifier annotation
*/
public static BindingKey of(Class type, Annotation annotation) {
return new BindingKey<>(type, annotation, annotation == null ? null : annotation.annotationType());
}
/**
* Constructs a new Binding Key for the specified type and the qualifier annotation.
* @param type the injection class
* @param annotationType the type of qualifier annotation defined for the type
* @param the type of of the class modeled by this key
* @return a new key with the specified type and the type of qualifier annotation
*/
public static BindingKey of(Class type, Class annotationType) {
return new BindingKey<>(type, null, annotationType);
}
/**
* Get the injection type of this key.
* @return the injection type of this key
*/
public Class getType() {
return type;
}
/**
* Get the the qualifier annotation specified in this key.
* @return the qualifier annotation
*/
private Annotation getAnnotation() {
return annotation;
}
/**
* Get the the type of qualifier annotation specified in this key.
* @return the type of qualifier annotation
*/
private Class getAnnotationType() {
return annotationType;
}
/**
* Create a new key to indicate that this key matches to a {@link javax.inject.Provider} of the type.
*
* Note: this key can only be used to get the instance from Injector, but not during binding.
* @return a new key that matches to the provider of this binding type and qualifier
*/
public BindingKey> toProviderType() {
return createBindingKey(true, multiBinding);
}
/**
* Create a new key to indicate that this key matches to a {@link java.util.List} or {@link java.util.Collection}
* of the given type bound using {@link io.github.pustike.inject.bind.MultiBinder}.
*
* Note: this key can only be used to get the instance from Injector, but not during binding.
* @return a new key that matches to the type bound using multiBinder
*/
public BindingKey> toListType() {
return createBindingKey(providerKey, true);
}
/**
* Create a new key to indicate that this key matches to a {@code List>}
* of the given type bound using {@link io.github.pustike.inject.bind.MultiBinder}.
*
* Note: this key can only be used to get the instance from Injector, but not during binding.
* @return a new key that matches to the type bound using multiBinder
*/
public BindingKey>> toListProviderType() {
return createBindingKey(true, true);
}
@SuppressWarnings("unchecked")
private BindingKey createBindingKey(boolean isProviderKey, boolean isMultiBinding) {
BindingKey bindingKey = new BindingKey<>(type, annotation, annotationType);
bindingKey.providerKey = isProviderKey;
bindingKey.multiBinding = isMultiBinding;
bindingKey.hashCode = 0;
return (BindingKey) bindingKey;
}
/**
* Returns true if this key is of {@link javax.inject.Provider} type.
* @return true if this key is of provider type.
*/
public boolean isProviderKey() {
return providerKey;
}
/**
* Uses the computed hash code of this key to check if the given object equals.
* @param obj the reference object with which to compare
* @return {@code true} if this object is the same as the obj argument; {@code false} otherwise
* @see #hashCode()
*/
@Override
public final boolean equals(Object obj) {
if (obj == this) {
return true;
}
if (!(obj instanceof BindingKey)) {
return false;
}
BindingKey other = (BindingKey) obj;
return hashCode() == other.hashCode();
}
/**
* Computes the hash code using hash codes of the binding type and qualifier annotation or annotation type.
* @return the hash code value for this key
*/
@Override
public int hashCode() {
return hashCode == 0 ? hashCode = computeHashCode() : hashCode;
}
/**
* Computes the hash code for this key.
*/
private int computeHashCode() {
int result = type.hashCode();
if (annotation != null) {
result = 31 * result + annotation.hashCode();
} else if (annotationType != null) {
result = 31 * result + AnnotationUtils.hashCode(annotationType);
}
return multiBinding ? 31 * result + Boolean.hashCode(true) : result;
}
/**
* Generates a string representation of the key using the binding type and qualifier annotation.
* @return a string representation of the binding key
*/
@Override
public String toString() {
return toString(this);
}
private static String toString(BindingKey key) {
String typeName = key.getType().getName();
typeName = key.providerKey ? "Provider<" + typeName + ">" : typeName;
typeName = key.multiBinding ? "List<" + typeName + ">" : typeName;
StringBuilder sb = new StringBuilder(typeName);
Annotation annotation = key.getAnnotation();
if (annotation != null) {
if (annotation instanceof Named) {
sb.append("@Named(\"").append(((Named) annotation).value()).append("\")");
} else {
sb.append('@').append(annotation);
}
} else if (key.getAnnotationType() != null) {
sb.append('@').append(key.getAnnotationType());
}
return sb.toString();
}
}