/*
 * Copyright (C) 2009 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.TypeLiteral;
import com.google.inject.matcher.Matcher;

/**
 * Binds types (picked using a Matcher) to an type listener. Registrations are created explicitly in
 * a module using {@link com.google.inject.Binder#bindListener(Matcher, TypeListener)} statements:
 *
 * <pre>
 *     register(only(new TypeLiteral&lt;PaymentService&lt;CreditCard>>() {}), listener);</pre>
 *
 * @author jessewilson@google.com (Jesse Wilson)
 * @since 2.0
 */
public final class TypeListenerBinding implements Element {

  private final Object source;
  private final Matcher<? super TypeLiteral<?>> typeMatcher;
  private final TypeListener listener;

  TypeListenerBinding(
      Object source, TypeListener listener, Matcher<? super TypeLiteral<?>> typeMatcher) {
    this.source = source;
    this.listener = listener;
    this.typeMatcher = typeMatcher;
  }

  /** Returns the registered listener. */
  public TypeListener getListener() {
    return listener;
  }

  /** Returns the type matcher which chooses which types the listener should be notified of. */
  public Matcher<? super TypeLiteral<?>> getTypeMatcher() {
    return typeMatcher;
  }

  @Override
  public Object getSource() {
    return source;
  }

  @Override
  public <T> T acceptVisitor(ElementVisitor<T> visitor) {
    return visitor.visit(this);
  }

  @Override
  public void applyTo(Binder binder) {
    binder.withSource(getSource()).bindListener(typeMatcher, listener);
  }
}
