/*
 * Copyright 2001-2004 The Apache Software Foundation.
 * 
 * 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.apache.commons.betwixt.io;


/** <p>Interface allowing pluggable <code>ID</code> attribute value generators.</p>
  *
  * <p> <code>IDGenerator</code>'s are used to generate <code>ID</code>
  * attribute values by <code>BeanWriter</code>. 
  * A user can specify the generation mechanism by passing an implementation to 
  * {@link BeanWriter#setIdGenerator}.</p>
  *
  * <p>Standard implementations are included with that supply random and sequantial values.</p>
  *
  * @author <a href="mailto:rdonkin@apache.org">Robert Burrell Donkin</a>
  * @version $Revision: 1.7 $
  */
public interface IDGenerator {
    
    /** 
      * Get the last <code>ID</code> value generated.
      *
      * @return the last value generated
      */
    public String getLastId();
    
    /** 
      * Generate a new  <code>ID</code> attribute value.
      *
      * @return next value
      */
    public String nextId();
}