uimaj-core/src/main/java/org/apache/uima/cas/impl/CopyOnWriteIndexPart.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.uima.cas.impl;

import java.util.Iterator;

import org.apache.uima.jcas.cas.TOP;

/**
 * common APIs supporting the copy on write aspect of index parts
 */
public interface CopyOnWriteIndexPart<T> {
  
  void makeReadOnlyCopy();
  
  /**
   * @return true if this cow version is the same as the original.
   *              true means the index has not been updated
   */
  boolean isOriginal();
  
  /**
   * @return The number of elements in the index
   */
  int size();
  
  /**
   * @return iterator over all the elements
   */
  Iterator<T> iterator();
  
  /**
   * Copy FS refs to target from this index part
   * @param target the target array to copy into
   * @param startingIndexInTarget the starting index in the target array
   * @return startingIndexInTarget + size
   */
  int copyToArray(TOP[] target, int startingIndexInTarget);
}