de.u808.simpleinquest.web.tags.VersionInfoTag.java Source code

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Here is the source code for de.u808.simpleinquest.web.tags.VersionInfoTag.java

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/*
 * Copyright 2008-2009 Andreas Friedel
 *
 * 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.u808.simpleinquest.web.tags;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.jar.Attributes;
import java.util.jar.Manifest;

import javax.servlet.jsp.JspException;
import javax.servlet.jsp.JspWriter;
import javax.servlet.jsp.PageContext;
import javax.servlet.jsp.tagext.SimpleTagSupport;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class VersionInfoTag extends SimpleTagSupport {

    private static Log log = LogFactory.getLog(VersionInfoTag.class);

    @Override
    public void doTag() throws JspException, IOException {
        PageContext pageContext = (PageContext) getJspContext();
        JspWriter out = pageContext.getOut();
        try {
            String appServerHome = pageContext.getServletContext().getRealPath("/");

            File manifestFile = new File(appServerHome, "META-INF/MANIFEST.MF");

            Manifest mf = new Manifest();
            mf.read(new FileInputStream(manifestFile));

            Attributes atts = mf.getMainAttributes();

            out.println("<span id=\"version\"> (Revision " + atts.getValue("Implementation-Version") + " Build "
                    + atts.getValue("Implementation-Build") + " Built-By " + atts.getValue("Built-By")
                    + ")</span>");
        } catch (Exception e) {
            log.error("Tag error", e);
        }
    }

}