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Lucene example source code file (CachingWrapperFilterHelper.java)

This example Lucene source code file (CachingWrapperFilterHelper.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

cache, cache, cachingwrapperfilter, cachingwrapperfilterhelper, cachingwrapperfilterhelper, docidset, docidset, io, ioexception, override, override, string

The Lucene CachingWrapperFilterHelper.java source code

package org.apache.lucene.search;

 * 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,
 * See the License for the specific language governing permissions and
 * limitations under the License.

import java.io.IOException;

import junit.framework.Assert;
import org.apache.lucene.index.IndexReader;

 * A unit test helper class to test when the filter is getting cached and when it is not.
public class CachingWrapperFilterHelper extends CachingWrapperFilter {
  private boolean shouldHaveCache = false;

   * @param filter Filter to cache results of
  public CachingWrapperFilterHelper(Filter filter) {
  public void setShouldHaveCache(boolean shouldHaveCache) {
    this.shouldHaveCache = shouldHaveCache;
  public synchronized DocIdSet getDocIdSet(IndexReader reader) throws IOException {

    final int saveMissCount = missCount;
    DocIdSet docIdSet = super.getDocIdSet(reader);

    if (shouldHaveCache) {
      Assert.assertEquals("Cache should have data ", saveMissCount, missCount);
    } else {
      Assert.assertTrue("Cache should be null " + docIdSet, missCount > saveMissCount);

    return docIdSet;

  public String toString() {
    return "CachingWrapperFilterHelper("+filter+")";

  public boolean equals(Object o) {
    if (!(o instanceof CachingWrapperFilterHelper)) return false;
    return this.filter.equals(o);
  public int hashCode() {
    return this.filter.hashCode() ^ 0x5525aacb;

Other Lucene examples (source code examples)

Here is a short list of links related to this Lucene CachingWrapperFilterHelper.java source code file:

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