org.apache.blur.index.IndexDeletionPolicyReader.java Source code

Introduction

Here is the source code for org.apache.blur.index.IndexDeletionPolicyReader.java

Source

/**
 * 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.
 */
package org.apache.blur.index;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexCommit;
import org.apache.lucene.index.IndexDeletionPolicy;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexReader.ReaderClosedListener;

public class IndexDeletionPolicyReader extends IndexDeletionPolicy {

    private final IndexDeletionPolicy _base;
    private final Set<Long> _gens = Collections.newSetFromMap(new ConcurrentHashMap<Long, Boolean>());

    public IndexDeletionPolicyReader(IndexDeletionPolicy base) {
        _base = base;
    }

    @Override
    public void onInit(List<? extends IndexCommit> commits) throws IOException {
        _base.onInit(commits);
    }

    @Override
    public void onCommit(List<? extends IndexCommit> commits) throws IOException {
        commits = removeCommitsStillInUse(commits);
        _base.onCommit(commits);
    }

    private List<? extends IndexCommit> removeCommitsStillInUse(List<? extends IndexCommit> commits) {
        List<IndexCommit> validForRemoval = new ArrayList<IndexCommit>();
        for (IndexCommit commit : commits) {
            if (!isStillInUse(commit)) {
                validForRemoval.add(commit);
            }
        }
        return validForRemoval;
    }

    public DirectoryReader register(DirectoryReader reader) throws IOException {
        final long generation = reader.getIndexCommit().getGeneration();
        register(generation);
        reader.addReaderClosedListener(new ReaderClosedListener() {
            @Override
            public void onClose(IndexReader reader) {
                unregister(generation);
            }
        });
        return reader;
    }

    private boolean isStillInUse(IndexCommit commit) {
        long generation = commit.getGeneration();
        return _gens.contains(generation);
    }

    public void register(long gen) {
        _gens.add(gen);
    }

    public void unregister(long gen) {
        _gens.remove(gen);
    }

}