org.kuali.student.common.util.ManifestInspector.java Source code

Introduction

Here is the source code for org.kuali.student.common.util.ManifestInspector.java

Source

/**
 * Copyright 2010 The Kuali Foundation 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 org.kuali.student.common.util;

import java.io.IOException;
import java.io.InputStream;
import java.util.jar.Attributes;
import java.util.jar.Manifest;

import javax.servlet.ServletContext;

import static org.apache.commons.io.IOUtils.*;
import static org.apache.commons.lang.StringUtils.*;

/**
 * Obtains version information about the application from the META-INF/MANIFEST.MF file contained inside a .war file
 */
public class ManifestInspector {

    /**
     * Location of the MANIFEST.MF file
     */
    public static final String MANIFEST_LOCATION = "/META-INF/MANIFEST.MF";
    public static final String BUNDLE_NAME = "Bundle-Name";
    public static final String BUNDLE_VERSION = "Bundle-Version";
    public static final String BUNDLE_TIMESTAMP = "Bundle-Timestamp";
    public static final String BUNDLE_BUILD_NUMBER = "Bundle-BuildNumber";
    public static final String NO_BUILD_INFORMATION_AVAILABLE = "No build information available";

    /**
     * Return a Manifest object
     */
    protected Manifest getManifest(ServletContext servletContext) throws IOException {
        InputStream in = null;
        try {
            in = servletContext.getResourceAsStream(MANIFEST_LOCATION);
            if (in == null) {
                return null;
            } else {
                return new Manifest(in);
            }
        } catch (IOException e) {
            throw e;
        } finally {
            closeQuietly(in);
        }
    }

    /**
     * Examine the manifest provided for build information. Returns null if manifest is null
     */
    protected BuildInformation getBuildInformation(Manifest manifest) {
        // No Manifest is available
        if (manifest == null) {
            return null;
        }

        // Extract the attributes
        Attributes attributes = manifest.getMainAttributes();

        // Manifest attributes containing the build information
        String name = attributes.getValue(BUNDLE_NAME);
        String version = attributes.getValue(BUNDLE_VERSION);
        String buildNumber = attributes.getValue(BUNDLE_BUILD_NUMBER);
        String timestamp = attributes.getValue(BUNDLE_TIMESTAMP);

        // Create and populate a BuildInformation object
        BuildInformation bi = new BuildInformation();
        bi.setName(name);
        bi.setVersion(version);
        bi.setBuildNumber(buildNumber);
        bi.setTimestamp(timestamp);
        return bi;
    }

    /**
     * Obtain version information from MANIFEST.MF
     */
    public String getBuildInformationString(ServletContext context) throws IOException {
        // Get a handle to a Manifest object
        Manifest manifest = getManifest(context);

        // Store build information attributes from the manifest into a POJO
        BuildInformation buildInformation = getBuildInformation(manifest);

        // Convert the POJO to a string
        return toString(buildInformation);
    }

    /**
     * Return true if BuildInformation is null or does not contain any meaningful information.
     */
    protected boolean isNullOrEmpty(BuildInformation bi) {
        if (bi == null) {
            return true;
        }
        if (!isEmpty(bi.getName())) {
            return false;
        }
        if (!isEmpty(bi.getVersion())) {
            return false;
        }
        if (!isEmpty(bi.getBuildNumber())) {
            return false;
        }
        if (!isEmpty(bi.getTimestamp())) {
            return false;
        }
        return true;
    }

    /**
     * Convert the build information POJO to a display String
     */
    public String toString(BuildInformation bi) {
        /**
         * For developers pointed at a local build, MANIFEST.MF may not be present
         * 
         * Since we overlay the Rice war file, the MANIFEST.MF from Rice may be present but doesn't contain build
         * information
         */
        if (isNullOrEmpty(bi)) {
            return NO_BUILD_INFORMATION_AVAILABLE;
        }

        /**
         * Build number is only present if Hudson has done the build
         */
        if (!isEmpty(bi.getBuildNumber())) {
            bi.setBuildNumber("#" + bi.getBuildNumber());
        }

        /**
         * Build a string out of the build information
         */
        //JIRA FIX : KSENROLL-8731 - Replaced StringBuffer with StringBuilder
        StringBuilder sb = new StringBuilder();
        if (!isEmpty(bi.getName())) {
            sb.append(bi.getName());
            sb.append(" :: ");
        }
        if (!isEmpty(bi.getVersion())) {
            sb.append(bi.getVersion());
            sb.append(" :: ");
        }
        if (!isEmpty(bi.getBuildNumber())) {
            sb.append(bi.getBuildNumber());
            sb.append(" :: ");
        }
        if (!isEmpty(bi.getTimestamp())) {
            sb.append(bi.getTimestamp());
        }
        return sb.toString();
    }
}