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,
* 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 java.util.BitSet;
import org.apache.lucene.index.IndexReader;
/**
* Provides caching of {@link Filter}s themselves on the remote end of an RMI connection.
* The cache is keyed on Filter's hashCode(), so if it sees the same filter twice
* it will reuse the original version.
* <p/>
* NOTE: This does NOT cache the Filter bits, but rather the Filter itself.
* Thus, this works hand-in-hand with {@link CachingWrapperFilter} to keep both
* file Filter cache and the Filter bits on the remote end, close to the searcher.
* <p/>
* Usage:
* <p/>
* To cache a result you must do something like
* RemoteCachingWrapperFilter f = new RemoteCachingWrapperFilter(new CachingWrapperFilter(myFilter));
* <p/>
* @author Matt Ericson
*/
public class RemoteCachingWrapperFilter extends Filter {
protected Filter filter;
public RemoteCachingWrapperFilter(Filter filter) {
this.filter = filter;
}
/**
* Uses the {@link FilterManager} to keep the cache for a filter on the
* searcher side of a remote connection.
* @param reader the index reader for the Filter
* @return the bitset
*/
public BitSet bits(IndexReader reader) throws IOException {
Filter cachedFilter = FilterManager.getInstance().getFilter(filter);
return cachedFilter.bits(reader);
}
}
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