001    /*
002     * SonarQube, open source software quality management tool.
003     * Copyright (C) 2008-2014 SonarSource
004     * mailto:contact AT sonarsource DOT com
005     *
006     * SonarQube is free software; you can redistribute it and/or
007     * modify it under the terms of the GNU Lesser General Public
008     * License as published by the Free Software Foundation; either
009     * version 3 of the License, or (at your option) any later version.
010     *
011     * SonarQube is distributed in the hope that it will be useful,
012     * but WITHOUT ANY WARRANTY; without even the implied warranty of
013     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
014     * Lesser General Public License for more details.
015     *
016     * You should have received a copy of the GNU Lesser General Public License
017     * along with this program; if not, write to the Free Software Foundation,
018     * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
019     */
020    package org.sonar.api.utils;
021    
022    import java.io.IOException;
023    import java.net.URL;
024    import java.util.ArrayList;
025    import java.util.Enumeration;
026    import java.util.List;
027    import java.util.jar.Attributes;
028    import java.util.jar.Manifest;
029    
030    /**
031     * @since 2.2
032     */
033    public final class ManifestUtils {
034    
035      private ManifestUtils() {
036      }
037    
038      /**
039       * Search for a property in all the manifests found in the classloader
040       *
041       * @return the values, an empty list if the property is not found.
042       */
043      public static List<String> getPropertyValues(ClassLoader classloader, String key) {
044        List<String> values = new ArrayList<String>();
045        try {
046          Enumeration<URL> resources = classloader.getResources("META-INF/MANIFEST.MF");
047          while (resources.hasMoreElements()) {
048            Manifest manifest = new Manifest(resources.nextElement().openStream());
049            Attributes attributes = manifest.getMainAttributes();
050            String value = attributes.getValue(key);
051            if (value != null) {
052              values.add(value);
053            }
054          }
055        } catch (IOException e) {
056          throw new SonarException("Fail to load manifests from classloader: " + classloader, e);
057        }
058        return values;
059      }
060    }