ch.entwine.weblounge.bridge.oaipmh.harvester.LastHarvested.java Source code

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Here is the source code for ch.entwine.weblounge.bridge.oaipmh.harvester.LastHarvested.java

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/**
 *  Copyright 2009, 2010 The Regents of the University of California
 *  Licensed under the Educational Community 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.osedu.org/licenses/ECL-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 ch.entwine.weblounge.bridge.oaipmh.harvester;

import static org.opencastproject.util.data.Option.none;
import static org.opencastproject.util.data.Option.some;

import ch.entwine.weblounge.bridge.oaipmh.util.PersistenceEnv;

import org.apache.commons.lang.ArrayUtils;
import org.opencastproject.util.data.Function;
import org.opencastproject.util.data.Option;

import java.util.Date;
import java.util.List;

import javax.persistence.Entity;
import javax.persistence.EntityManager;
import javax.persistence.Id;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
import javax.persistence.NoResultException;
import javax.persistence.Query;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

/**
 * Persists the last harvested time of a url.
 */
@Entity
@Table(name = "LAST_HARVESTED")
@NamedQueries({
        @NamedQuery(name = "findLastHarvested", query = "SELECT a.timestamp FROM LastHarvested a WHERE a.url = :url"),
        @NamedQuery(name = "findAll", query = "SELECT a FROM LastHarvested a") })
public class LastHarvested {

    @Id
    private String url;

    @Temporal(TemporalType.TIMESTAMP)
    private Date timestamp;

    /**
     * JPA constructor.
     */
    public LastHarvested() {
    }

    public LastHarvested(String url, Date timestamp) {
        this.url = url;
        this.timestamp = timestamp;
    }

    public String getUrl() {
        return url;
    }

    public Date getTimestamp() {
        return timestamp;
    }

    public static Option<Date> getLastHarvestDate(PersistenceEnv penv, final String url) {
        return penv.tx(new Function<EntityManager, Option<Date>>() {
            public Option<Date> apply(EntityManager em) {
                Query q = em.createNamedQuery("findLastHarvested");
                q.setParameter("url", url);
                try {
                    return some((Date) q.getSingleResult());
                } catch (NoResultException e) {
                    return none();
                }
            }
        });
    }

    /**
     * Save or update a timestamp.
     */
    public static void update(PersistenceEnv penv, final LastHarvested entity) {
        penv.tx(new Function<EntityManager, Void>() {
            public Void apply(EntityManager em) {
                LastHarvested existing = em.find(LastHarvested.class, entity.getUrl());
                if (existing != null) {
                    em.persist(em.merge(entity));
                } else {
                    em.persist(entity);
                }
                return null;
            }
        });
    }

    /**
     * Remove all URLs from the table that do not exist in <code>keepUrls</code>.
     */
    public static void cleanup(PersistenceEnv penv, final String[] keepUrls) {
        penv.tx(new Function<EntityManager, Void>() {
            public Void apply(EntityManager em) {
                List<LastHarvested> lhs = em.createNamedQuery("findAll").getResultList();
                for (LastHarvested lh : lhs) {
                    if (!ArrayUtils.contains(keepUrls, lh.getUrl())) {
                        em.remove(lh);
                    }
                }
                return null;
            }
        });
    }
}