/**
 * 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.util;

import static com.google.inject.internal.Preconditions.checkNotNull;
import java.io.Serializable;
import java.lang.annotation.Annotation;
import javax.inject.Named;
import javax.inject.Provider;

/**
 * Utility methods for use with <a href="http://code.google.com/p/atinject/">JSR
 * 330</a>.
 *
 * @author jessewilson@google.com (Jesse Wilson)
 */
public class Jsr330 {

  private Jsr330() {}

  public static Named named(String name) {
    return new NamedImpl(name);
  }

  /**
   * Returns a Guice-friendly {@code com.google.inject.Provider} for the given
   * JSR-330 {@code javax.inject.Provider}. The converse method is unnecessary,
   * since Guice providers directly implement the JSR-330 interface.
   */
  public static <T> com.google.inject.Provider<T> guicify(Provider<T> provider) {
    if (provider instanceof com.google.inject.Provider) {
      return (com.google.inject.Provider<T>) provider;
    }

    final Provider<T> delegate = checkNotNull(provider, "provider");
    return new com.google.inject.Provider<T>() {
      public T get() {
        return delegate.get();
      }

      @Override public String toString() {
        return "guicified(" + delegate + ")";
      }
    };
  }

  // TODO: support binding properties like Names does?

  private static class NamedImpl implements Named, Serializable {
    private final String value;

    NamedImpl(String value) {
      this.value = checkNotNull(value, "name");
    }

    public String value() {
      return value;
    }

    @Override public int hashCode() {
      // This is specified in java.lang.Annotation.
      return (127 * "value".hashCode()) ^ value.hashCode();
    }

    @Override public boolean equals(Object o) {
      if (!(o instanceof Named)) {
        return false;
      }

      Named other = (Named) o;
      return value.equals(other.value());
    }

    @Override public String toString() {
      return "@" + Named.class.getName() + "(value=" + value + ")";
    }

    public Class<? extends Annotation> annotationType() {
      return Named.class;
    }

    private static final long serialVersionUID = 0;
  }
}