de.codesourcery.eve.skills.db.dao.FactionDAO.java Source code

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Here is the source code for de.codesourcery.eve.skills.db.dao.FactionDAO.java

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/**
 * Copyright 2004-2009 Tobias Gierke <tobias.gierke@code-sourcery.de>
 *
 * 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 de.codesourcery.eve.skills.db.dao;

import java.util.HashMap;
import java.util.Map;
import java.util.NoSuchElementException;

import org.apache.commons.lang.StringUtils;
import org.apache.log4j.Logger;

import de.codesourcery.eve.skills.db.datamodel.Faction;

public class FactionDAO extends HibernateDAO<Faction, Long> implements IFactionDAO {

    public static final Logger log = Logger.getLogger(FactionDAO.class);

    // thread-safe , immutable map
    private Map<Long, Faction> byIdCache;

    // thread-safe , immutable map
    private Map<String, Faction> byNameCache;

    private final Object LOCK = new Object();
    private volatile boolean initialized = false;

    public FactionDAO() {
        super(Faction.class);
    }

    protected void load() {

        synchronized (LOCK) {

            if (initialized) {
                return;
            }

            final Map<String, Faction> tmpByNameMap = new HashMap<String, Faction>();

            final Map<Long, Faction> tmpByIDMap = new HashMap<Long, Faction>();

            for (Faction f : fetchAll()) {
                tmpByNameMap.put(f.getName(), f);
                tmpByIDMap.put(f.getID(), f);
            }

            log.debug("load(): Loaded " + byNameCache.size() + " factions from database.");

            this.byNameCache = tmpByNameMap;
            this.byIdCache = tmpByIDMap;

            initialized = true;
        }
    }

    @Override
    public Faction getFactionByName(String factionName) throws NoSuchElementException {

        if (StringUtils.isBlank(factionName)) {
            throw new IllegalArgumentException("factionName cannot be blank.");
        }

        if (!initialized) { // thread-safe because of volatile semantics
            load();
        }

        final Faction result = this.byNameCache.get(factionName);

        if (result == null) {
            throw new NoSuchElementException("Found no faction with name '" + factionName + "'");
        }
        return result;
    }

}