org.hibernate.search.reader.impl.CacheableMultiReader.java Source code

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Here is the source code for org.hibernate.search.reader.impl.CacheableMultiReader.java

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/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2010, Red Hat, Inc. and/or its affiliates or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat, Inc.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.search.reader.impl;

import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.MultiReader;
import org.hibernate.search.SearchException;
import org.hibernate.search.indexes.spi.ReaderProvider;

/**
 * MultiReader ensuring equals returns true if the underlying readers are the same (and in the same order)
 * Especially useful when using {@link org.apache.lucene.search.CachingWrapperFilter}
 *
 * @author Emmanuel Bernard
 * @author Sanne Grinovero <sanne@hibernate.org> (C) 2011 Red Hat Inc.
 */
public class CacheableMultiReader extends MultiReader {

    // This is package private as the intention of the Lucene team seems to be to not 
    // expose this publically (it's a protected member in Lucene 2.3)
    final IndexReader[] subReaders;
    final ReaderProvider[] managers;

    public CacheableMultiReader(IndexReader[] subReaders, ReaderProvider[] managers) {
        // don't allow sub readers to be closed:
        super(subReaders, false);
        this.subReaders = subReaders;
        this.managers = managers;
    }

    @Override
    public final void decRef() {
        avoidUsingThis();
    }

    @Override
    public final synchronized IndexReader reopen() {
        avoidUsingThis();
        return null; //never reached, make compiler happy
    }

    @Override
    public final void incRef() {
        avoidUsingThis();
    }

    @Override
    public boolean equals(Object obj) {
        // Equality only checks for subReaders as an equal sub-IndexReader is certainly coming from the same ReaderProvider.
        if (this == obj)
            return true;
        if (!(obj instanceof CacheableMultiReader))
            return false;
        CacheableMultiReader that = (CacheableMultiReader) obj;
        int length = this.subReaders.length;
        if (length != that.subReaders.length)
            return false;
        for (int index = 0; index < length; index++) {
            if (!this.subReaders[index].equals(that.subReaders[index]))
                return false;
        }
        return true;
    }

    @Override
    public int hashCode() {
        int result = 0;
        for (Object reader : this.subReaders) {
            result = 31 * result + reader.hashCode();
        }
        return result;
    }

    private void avoidUsingThis() {
        throw new SearchException("IndexReader lifecycle should not be managed, please use "
                + "org.hibernate.search.SearchFactory.closeIndexReader(IndexReader) to close IndexReader instances or pool them.");
    }

}