IndexReaderDecorator.java

package proj.zoie.api.indexing;
/**
 * 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.
 */
import java.io.IOException;

import org.apache.lucene.index.IndexReader;
import proj.zoie.api.ZoieIndexReader;

/**
 * Decorates a {@link proj.zoie.api.ZoieIndexReader} to a customized {@link org.apache.lucene.index.IndexReader}.
 * @see org.apache.lucene.index.FilterIndexReader
 */
public interface IndexReaderDecorator<R extends IndexReader>
{
	/**
	 * Do the decoration
	 * @param indexReader source reader
	 * @return a decorated reader
	 * @throws IOException
	 */
	R decorate(ZoieIndexReader<R> indexReader) throws IOException;
	
	/**
	 * This is called when the actual underlysing reader was not changed, but a new reference was created. Normally only the internal
	 * reference to the source reader needs to be set.
	 * @param decorated Previously decoreated reader
	 * @param copy a new copy of the source reader
	 * @return Re-decorated reader
	 * @throws IOException
	 */
	R redecorate(R decorated,ZoieIndexReader<R> copy) throws IOException;
}