net.sf.lucis.core.impl.EmptyDirectory.java Source code

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Here is the source code for net.sf.lucis.core.impl.EmptyDirectory.java

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/*
 * Copyright (C) the original author or authors.
 *
 * Licensed 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 net.sf.lucis.core.impl;

import java.io.IOException;

import net.sf.lucis.core.Factory;

import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.RAMDirectory;

/**
 * Empty Directory.
 * @author Andres Rodriguez
 */
final class EmptyDirectory {
    /** Not instantiable. */
    private EmptyDirectory() {
        throw new AssertionError();
    }

    private static volatile Directory directory = null;

    public static Directory get() throws IOException {
        if (directory != null) {
            return directory;
        }
        create();
        return directory;
    }

    private static synchronized void create() throws IOException {
        if (directory != null) {
            return;
        }
        final RAMDirectory ram = new RAMDirectory();
        IndexWriter w = new IndexWriter(ram, Factory.get().writerConfig());
        w.commit();
        w.close();
        directory = ram;
    }
}