Responsibility.java

/**
 * Copyright 2010 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.client.editor;

/**
 * Used to distinguish between locally sourced operations that are a direct
 * result of user action from those that are indirect.
 *
 * For example, typing would normally be considered a direct operation, whereas
 * a background task that annotates the document in response to a user action,
 * even just automatically, would be indirect.
 *
 * @author danilatos@google.com (Daniel Danilatos)
 */
public interface Responsibility {

  /**
   * Identifies the responsibility of currently generated locally sourced
   * operations
   */
  public interface Manager extends Responsibility {
    /**
     * Indicates the start of a sequence of operations directly caused by the
     * user.
     *
     * Indirect and direct sequences may nest within eachother
     */
    void startDirectSequence();

    /**
     * End of sequence started by {@link #startDirectSequence()}
     */
    void endDirectSequence();

    /**
     * Indicates the start of a sequence of operations not directly caused by the
     * user.
     *
     * Indirect and direct sequences may nest within eachother
     */
    void startIndirectSequence();

    /**
     * End of sequence started by {@link #endIndirectSequence()}
     */
    void endIndirectSequence();
  }

  /**
   * @return true if local ops currently being applied are "direct"
   */
  boolean withinDirectSequence();
}