org.elasticsearch.common.inject.spi.Dependency Maven / Gradle / Ivy
/*
* Copyright (C) 2008 Google Inc.
*
* 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 org.elasticsearch.common.inject.spi;
import org.elasticsearch.common.inject.Key;
import java.util.HashSet;
import java.util.Objects;
import java.util.Set;
import static java.util.Collections.unmodifiableSet;
/**
* A variable that can be resolved by an injector.
*
* Use {@link #get} to build a freestanding dependency, or {@link InjectionPoint} to build one
* that's attached to a constructor, method or field.
*
* @author [email protected] (Bob Lee)
* @author [email protected] (Jesse Wilson)
* @since 2.0
*/
public final class Dependency {
private final InjectionPoint injectionPoint;
private final Key key;
private final boolean nullable;
private final int parameterIndex;
Dependency(InjectionPoint injectionPoint, Key key,
boolean nullable, int parameterIndex) {
this.injectionPoint = injectionPoint;
this.key = key;
this.nullable = nullable;
this.parameterIndex = parameterIndex;
}
/**
* Returns a new dependency that is not attached to an injection point. The returned dependency is
* nullable.
*/
public static Dependency get(Key key) {
return new Dependency<>(null, key, true, -1);
}
/**
* Returns the dependencies from the given injection points.
*/
public static Set> forInjectionPoints(Set injectionPoints) {
Set> dependencies = new HashSet<>();
for (InjectionPoint injectionPoint : injectionPoints) {
dependencies.addAll(injectionPoint.getDependencies());
}
return unmodifiableSet(dependencies);
}
/**
* Returns the key to the binding that satisfies this dependency.
*/
public Key getKey() {
return this.key;
}
/**
* Returns true if null is a legal value for this dependency.
*/
public boolean isNullable() {
return nullable;
}
/**
* Returns the injection point to which this dependency belongs, or null if this dependency isn't
* attached to a particular injection point.
*/
public InjectionPoint getInjectionPoint() {
return injectionPoint;
}
/**
* Returns the index of this dependency in the injection point's parameter list, or {@code -1} if
* this dependency does not belong to a parameter list. Only method and constructor dependencies
* are elements in a parameter list.
*/
public int getParameterIndex() {
return parameterIndex;
}
@Override
public int hashCode() {
return Objects.hash(injectionPoint, parameterIndex, key);
}
@Override
public boolean equals(Object o) {
if (o instanceof Dependency) {
Dependency dependency = (Dependency) o;
return Objects.equals(injectionPoint, dependency.injectionPoint)
&& Objects.equals(parameterIndex, dependency.parameterIndex)
&& Objects.equals(key, dependency.key);
} else {
return false;
}
}
@Override
public String toString() {
StringBuilder builder = new StringBuilder();
builder.append(key);
if (injectionPoint != null) {
builder.append("@").append(injectionPoint);
if (parameterIndex != -1) {
builder.append("[").append(parameterIndex).append("]");
}
}
return builder.toString();
}
}