org.agnitas.dao.impl.VersionControlDaoImpl.java Source code

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Here is the source code for org.agnitas.dao.impl.VersionControlDaoImpl.java

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/*********************************************************************************
 * The contents of this file are subject to the Common Public Attribution
 * License Version 1.0 (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.openemm.org/cpal1.html. The License is based on the Mozilla
 * Public License Version 1.1 but Sections 14 and 15 have been added to cover
 * use of software over a computer network and provide for limited attribution
 * for the Original Developer. In addition, Exhibit A has been modified to be
 * consistent with Exhibit B.
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License for
 * the specific language governing rights and limitations under the License.
 * 
 * The Original Code is OpenEMM.
 * The Original Developer is the Initial Developer.
 * The Initial Developer of the Original Code is AGNITAS AG. All portions of
 * the code written by AGNITAS AG are Copyright (c) 2007 AGNITAS AG. All Rights
 * Reserved.
 * 
 * Contributor(s): AGNITAS AG. 
 ********************************************************************************/
package org.agnitas.dao.impl;

import org.agnitas.beans.VersionObject;
import org.agnitas.beans.impl.VersionObjectImpl;
import org.agnitas.dao.VersionControlDao;
import org.agnitas.util.AgnUtils;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.log4j.Logger;

public class VersionControlDaoImpl implements VersionControlDao {

    private static final transient Logger logger = Logger.getLogger(VersionControlDaoImpl.class);

    private static final int CONNECTION_TIMEOUT = 5000;
    private static final String URL = AgnUtils.getDefaultValue("system.updateserver") + "/version/"
            + AgnUtils.getCurrentVersion() + "/current_version.html";
    private static final String VERSION_KEY = "currentVersion";
    private static final long MAX_AGE = 60 * 60 * 1000L; // one hour cache time
    private static VersionObject versionObject = null;
    private long lastRefresh = 0L;

    /* (non-Javadoc)
     * @see org.agnitas.dao.VersionControlDao#getServerVersion()
     */
    @Override
    public VersionObject getServerVersion(String currentVersion, String referrer) {
        checkRefresh(currentVersion, referrer);
        return versionObject;
    }

    private void checkRefresh(String currentVersion, String referrer) {
        if (versionObject == null || System.currentTimeMillis() - lastRefresh > MAX_AGE) {
            String serverVersion = fetchServerVersion(currentVersion, referrer);
            versionObject = new VersionObjectImpl(currentVersion, serverVersion);
            lastRefresh = System.currentTimeMillis();
        }
    }

    private String fetchServerVersion(String currentVersion, String referrer) {
        HttpClient client = new HttpClient();
        client.setConnectionTimeout(CONNECTION_TIMEOUT);
        HttpMethod method = new GetMethod(URL);
        method.setRequestHeader("referer", referrer);
        NameValuePair[] queryParams = new NameValuePair[1];
        queryParams[0] = new NameValuePair(VERSION_KEY, currentVersion);
        method.setQueryString(queryParams);
        method.setFollowRedirects(true);
        String responseBody = null;

        try {
            client.executeMethod(method);
            responseBody = method.getResponseBodyAsString();
        } catch (Exception he) {
            logger.error("HTTP error connecting to '" + URL + "'", he);
        }

        //clean up the connection resources
        method.releaseConnection();
        return responseBody;
    }
}