com.opensearchserver.affinities.AffinityList.java Source code

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Here is the source code for com.opensearchserver.affinities.AffinityList.java

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/**
 * Copyright 2015 OpenSearchServer Inc.
 *
 * 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 com.opensearchserver.affinities;

import java.io.File;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.locks.ReadWriteLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;

import org.apache.commons.lang3.StringUtils;

import com.fasterxml.jackson.core.JsonGenerationException;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.opensearchserver.affinities.model.Affinity;
import com.opensearchserver.utils.json.JsonFileFilter;
import com.opensearchserver.utils.json.JsonMapper;

public class AffinityList {

    public volatile static AffinityList INSTANCE = null;

    private final ReadWriteLock rwl = new ReentrantReadWriteLock();

    private final File directory;

    private final Map<String, Affinity> affinities;

    private volatile Map<String, Affinity> affinitiesCache;

    public static void load(File directory) throws IOException {
        if (INSTANCE != null)
            throw new IOException("Already loaded");
        INSTANCE = new AffinityList(directory);
    }

    private AffinityList(File directory)
            throws JsonGenerationException, JsonMappingException, JsonParseException, IOException {
        this.directory = directory;
        this.affinities = new HashMap<String, Affinity>();
        load();
    }

    private File getFile(String name) {
        return new File(directory, name + ".json");
    }

    public void load() throws JsonGenerationException, JsonMappingException, JsonParseException, IOException {
        try {
            File[] files = directory.listFiles(JsonFileFilter.INSTANCE);
            if (files == null)
                return;
            for (File file : files) {
                String name = file.getName();
                name = name.substring(0, name.length() - 5);
                set(name, JsonMapper.MAPPER.readValue(file, Affinity.class));
            }
        } finally {
            buildCache();
        }
    }

    private void buildCache() {
        affinitiesCache = new HashMap<String, Affinity>(affinities);
    }

    public Affinity delete(String name) {
        if (StringUtils.isEmpty(name))
            return null;
        rwl.writeLock().lock();
        try {
            getFile(name).delete();
            Affinity affinity = affinities.remove(name);
            buildCache();
            return affinity;
        } finally {
            rwl.writeLock().unlock();
        }
    }

    public void set(String name, Affinity affinity)
            throws JsonGenerationException, JsonMappingException, IOException {
        if (affinity == null)
            return;
        if (StringUtils.isEmpty(name))
            return;
        rwl.writeLock().lock();
        try {
            JsonMapper.MAPPER.writeValue(getFile(name), affinity);
            affinities.put(name, affinity);
            buildCache();
        } finally {
            rwl.writeLock().unlock();
        }
    }

    public Affinity get(String name) {
        return affinitiesCache.get(name);
    }

    public Set<String> nameSet() {
        return affinitiesCache.keySet();
    }
}