Java example source code file (DependencyAndSource.java)

This example Java source code file (DependencyAndSource.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

class, dependency, dependencyandsource, member, object, override, reflection, string

The DependencyAndSource.java Java example source code

/*
 * Copyright (C) 2011 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 com.google.inject.spi;

import com.google.inject.Binder;
import com.google.inject.Binding;
import com.google.inject.Injector;
import com.google.inject.internal.util.StackTraceElements;

import java.lang.reflect.Member;

/**
 * A combination of a {@link Dependency} and the {@link Binding#getSource()
 * source} where the dependency was bound.
 * 
 * @author sameb@google.com (Sam Berlin)
 * @since 4.0
 */
public final class DependencyAndSource {
  private final Dependency<?> dependency;
  private final Object source;

  public DependencyAndSource(Dependency<?> dependency, Object source) {
    this.dependency = dependency;
    this.source = source;
  }

  /**
   * Returns the Dependency, if one exists. For anything that can be referenced
   * by {@link Injector#getBinding}, a dependency exists. A dependency will not
   * exist (and this will return null) for types initialized with
   * {@link Binder#requestInjection} or {@link Injector#injectMembers(Object)},
   * nor will it exist for objects injected into Providers bound with
   * LinkedBindingBuilder#toProvider(Provider).
   */
  public Dependency<?> getDependency() {
    return dependency;
  }

  /**
   * Returns a string describing where this dependency was bound. If the binding
   * was just-in-time, there is no valid binding source, so this describes the
   * class in question.
   */
  public String getBindingSource() {
    if (source instanceof Class) {
      return StackTraceElements.forType((Class) source).toString();
    } else if (source instanceof Member) {
      return StackTraceElements.forMember((Member) source).toString();
    } else {
      return source.toString();
    }
  }

  @Override
  public String toString() {
    Dependency<?> dep = getDependency();
    Object source = getBindingSource();
    if (dep != null) {
      return "Dependency: " + dep + ", source: " + source;
    } else {
      return "Source: " + source;
    }
  }
}