/**
 * Copyright 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.waveprotocol.wave.model.testing;

import org.waveprotocol.wave.model.operation.Operation;
import org.waveprotocol.wave.model.operation.SilentOperationSink;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

/**
 * A place where you can get a concrete OperationSink.Silent for testing.
 *
 * @author zdwang@google.com (David Wang)
 */
public class FakeSilentOperationSink<T extends Operation<?>> implements SilentOperationSink<T> {
  private LinkedList<T> ops = new LinkedList<T>();

  /**
   * For unit testing
   * @return the most recently consumed op
   */
  public T getConsumedOp() {
    int size = ops.size();
    return (size == 0) ? null : (ops.get(size - 1));
  }

  /**
   * {@inheritDoc}
   */
  public void consume(T op) {
    ops.addLast(op);
  }

  /**
   * Clears the list of saved operations.
   */
  public void clear() {
    ops.clear();
  }

  /**
   * Gets the list of operations consumed by this sink since it was last
   * cleared.
   *
   * @return the ops, from first consumed through most recently consumed.
   */
  public List<T> getOps() {
    return Collections.unmodifiableList(ops);
  }
}