package org.apache.maven.index.context;
/*
* 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.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.MultiReader;
import org.apache.lucene.search.IndexSearcher;
public class NexusIndexMultiReader
{
private final List<IndexingContext> contexts;
private List<IndexSearcher> searchers;
public NexusIndexMultiReader( final Collection<IndexingContext> contexts )
{
this.contexts = Collections.unmodifiableList( new ArrayList<IndexingContext>( contexts ) );
}
public synchronized IndexReader acquire()
throws IOException
{
if ( searchers != null )
{
release();
throw new IllegalStateException( "acquire() called 2nd time without release() in between!" );
}
this.searchers = new ArrayList<IndexSearcher>();
final ArrayList<IndexReader> contextReaders = new ArrayList<IndexReader>( contexts.size() );
for ( IndexingContext ctx : contexts )
{
final IndexSearcher indexSearcher = ctx.acquireIndexSearcher();
searchers.add( indexSearcher );
contextReaders.add( indexSearcher.getIndexReader() );
}
return new MultiReader( contextReaders.toArray( new IndexReader[contextReaders.size()] ) );
}
public synchronized void release()
throws IOException
{
if ( searchers != null )
{
final Iterator<IndexingContext> ic = contexts.iterator();
final Iterator<IndexSearcher> is = searchers.iterator();
while ( ic.hasNext() && is.hasNext() )
{
ic.next().releaseIndexSearcher( is.next() );
}
if ( ic.hasNext() || is.hasNext() )
{
throw new IllegalStateException( "Context and IndexSearcher mismatch: " + contexts + " vs " + searchers );
}
}
searchers = null;
}
/**
* Watch out with this method, as it's use depends on (if you control it at all) was {@link #acquire()} method
* invoked at all or not. Returns {@code null} if not, otherwise the list of acquired searchers. Not thread safe.
*
* @return
*/
public synchronized List<IndexSearcher> getAcquiredSearchers()
{
return searchers;
}
}