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Lucene example source code file (PayloadProcessorProvider.java)

This example Lucene source code file (PayloadProcessorProvider.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Java - Lucene tags/keywords

dirpayloadprocessor, dirpayloadprocessor, io, ioexception, ioexception, payloadprocessor, payloadprocessor, payloadprocessorprovider, payloadprocessorprovider

The Lucene PayloadProcessorProvider.java source code

package org.apache.lucene.index;

/**
 * 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.store.Directory;

/**
 * Provides a {@link DirPayloadProcessor} to be used for a {@link Directory}.
 * This allows using different {@link DirPayloadProcessor}s for different
 * directories, for e.g. to perform different processing of payloads of
 * different directories.
 * <p>
 * <b>NOTE: to avoid processing payloads of certain directories, you can
 * return <code>null in {@link #getDirProcessor}.
 * <p>
 * <b>NOTE: it is possible that the same {@link DirPayloadProcessor} will be
 * requested for the same {@link Directory} concurrently. Therefore, to avoid
 * concurrency issues you should return different instances for different
 * threads. Usually, if your {@link DirPayloadProcessor} does not maintain state
 * this is not a problem. The merge code ensures that the
 * {@link DirPayloadProcessor} instance you return will be accessed by one
 * thread to obtain the {@link PayloadProcessor}s for different terms.
 * 
 * @lucene.experimental
 */
public abstract class PayloadProcessorProvider {

  /**
   * Returns a {@link PayloadProcessor} for a given {@link Term} which allows
   * processing the payloads of different terms differently. If you intent to
   * process all your payloads the same way, then you can ignore the given term.
   * <p>
   * <b>NOTE: if you protect your {@link DirPayloadProcessor} from
   * concurrency issues, then you shouldn't worry about any such issues when
   * {@link PayloadProcessor}s are requested for different terms.
   */
  public static abstract class DirPayloadProcessor {

    /** Returns a {@link PayloadProcessor} for the given term. */
    public abstract PayloadProcessor getProcessor(Term term) throws IOException;
    
  }

  /**
   * Processes the given payload. One should call {@link #payloadLength()} to
   * get the length of the processed payload.
   * 
   * @lucene.experimental
   */
  public static abstract class PayloadProcessor {

    /** Returns the length of the payload that was returned by {@link #processPayload}. */
    public abstract int payloadLength() throws IOException;

    /**
     * Process the incoming payload and returns the resulting byte[]. Note that
     * a new array might be allocated if the given array is not big enough. The
     * length of the new payload data can be obtained via
     * {@link #payloadLength()}.
     */
    public abstract byte[] processPayload(byte[] payload, int start, int length) throws IOException;

  }

  /**
   * Returns a {@link DirPayloadProcessor} for the given {@link Directory},
   * through which {@link PayloadProcessor}s can be obtained for each
   * {@link Term}, or <code>null if none should be used.
   */
  public abstract DirPayloadProcessor getDirProcessor(Directory dir) throws IOException;

}

Other Lucene examples (source code examples)

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