geode-core/src/main/java/org/apache/geode/internal/cache/extension/SimpleExtensionPoint.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license
 * agreements. See the NOTICE file distributed with this work for additional information regarding
 * copyright ownership. The ASF licenses this file to You 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.apache.geode.internal.cache.extension;

import java.util.ArrayList;

import org.apache.geode.cache.Cache;
import org.apache.geode.internal.util.CollectionUtils;

/**
 * Simple implementation of {@link ExtensionPoint} for easy integration with existing objects.
 *
 *
 * @since GemFire 8.1
 */
// UnitTest SimpleExtensionPointJUnitTest
public class SimpleExtensionPoint<T> implements ExtensionPoint<T> {

  protected final ArrayList<Extension<T>> extensions = new ArrayList<Extension<T>>();

  protected final Iterable<Extension<T>> iterable =
      CollectionUtils.unmodifiableIterable(extensions);

  protected final Extensible<T> extensible;

  protected final T target;

  /**
   * Construct a new {@link SimpleExtensionPoint} around the given extensible target.
   *
   * @param extensible the {@link Extensible} object this extension point acts on.
   *
   * @param target the <code>T</code> instance being extended. Likely the same as
   *        <code>exensible</code>.
   * @since GemFire 8.1
   */
  public SimpleExtensionPoint(final Extensible<T> extensible, final T target) {
    this.extensible = extensible;
    this.target = target;
  }

  @Override
  public Iterable<Extension<T>> getExtensions() {
    return iterable;
  }

  @Override
  public void addExtension(Extension<T> extension) {
    extensions.add(extension);
  }

  @Override
  public void removeExtension(Extension<T> extension) {
    extensions.remove(extension);
  }

  @Override
  public T getTarget() {
    return target;
  }

  public void beforeCreate(final Cache cache) {
    for (final Extension<T> extension : extensions) {
      extension.beforeCreate(extensible, cache);
    }
  }

  public void fireCreate(final Extensible<T> newTarget) {
    for (final Extension<T> extension : extensions) {
      extension.onCreate(extensible, newTarget);
    }
  }
}