imporve plugin system

scm-webapp/src/main/java/sonia/scm/plugin/DefaultPluginLoader.java

@@ -0,0 +1,239 @@
+/**
+ * Copyright (c) 2010, Sebastian Sdorra
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ * 3. Neither the name of SCM-Manager; nor the names of its
+ *    contributors may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * http://bitbucket.org/sdorra/scm-manager
+ *
+ */
+
+
+
+package sonia.scm.plugin;
+
+//~--- non-JDK imports --------------------------------------------------------
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import sonia.scm.SCMContext;
+import sonia.scm.plugin.ext.ExtensionObject;
+import sonia.scm.plugin.ext.ExtensionProcessor;
+import sonia.scm.plugin.ext.JARExtensionScanner;
+import sonia.scm.util.IOUtil;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+
+import java.net.URL;
+
+import java.util.Collection;
+import java.util.Enumeration;
+import java.util.HashSet;
+import java.util.Set;
+
+import javax.xml.bind.JAXB;
+
+/**
+ *
+ * @author Sebastian Sdorra
+ */
+public class DefaultPluginLoader implements PluginLoader
+{
+
+  /** Field description */
+  public static final String PATH_PLUGINCONFIG = "META-INF/scm/plugin.xml";
+
+  /** the logger for DefaultPluginLoader */
+  private static final Logger logger =
+    LoggerFactory.getLogger(DefaultPluginLoader.class);
+
+  //~--- constructors ---------------------------------------------------------
+
+  /**
+   * Constructs ...
+   *
+   */
+  public DefaultPluginLoader()
+  {
+    ClassLoader classLoader = getClassLoader();
+
+    try
+    {
+      load(classLoader);
+    }
+    catch (IOException ex)
+    {
+      throw new RuntimeException(ex);
+    }
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param processor
+   */
+  @Override
+  public void processExtensions(ExtensionProcessor processor)
+  {
+    Set<ExtensionObject> extensions = new HashSet<ExtensionObject>();
+    ClassLoader classLoader = getClassLoader();
+    JARExtensionScanner scanner = new JARExtensionScanner();
+
+    for (Plugin plugin : installedPlugins)
+    {
+      InputStream input = null;
+
+      try
+      {
+        Set<String> packageSet = plugin.getPackageSet();
+
+        if (packageSet == null)
+        {
+          packageSet = new HashSet<String>();
+        }
+
+        packageSet.add(SCMContext.DEFAULT_PACKAGE);
+        input = new FileInputStream(plugin.getPath());
+        scanner.processExtensions(classLoader, extensions, input, packageSet);
+      }
+      catch (IOException ex)
+      {
+        logger.error(ex.getMessage(), ex);
+      }
+      finally
+      {
+        IOUtil.close(input);
+      }
+    }
+
+    for (ExtensionObject exo : extensions)
+    {
+      processor.processExtension(exo.getExtension(), exo.getExtensionClass());
+    }
+  }
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  @Override
+  public Collection<Plugin> getInstalledPlugins()
+  {
+    return installedPlugins;
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param classLoader
+   *
+   * @throws IOException
+   */
+  private void load(ClassLoader classLoader) throws IOException
+  {
+    Enumeration<URL> urlEnum = classLoader.getResources(PATH_PLUGINCONFIG);
+
+    if (urlEnum != null)
+    {
+      while (urlEnum.hasMoreElements())
+      {
+        URL url = urlEnum.nextElement();
+
+        loadPlugin(url);
+      }
+    }
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param url
+   */
+  private void loadPlugin(URL url)
+  {
+    try
+    {
+
+      // jar:file:/some/path/file.jar!/META-INF/scm/plugin.xml
+      String path = url.toExternalForm();
+
+      path = path.substring("jar:file:".length(), path.lastIndexOf("!"));
+
+      if (logger.isInfoEnabled())
+      {
+        logger.info("load plugin {}", path);
+      }
+
+      Plugin plugin = JAXB.unmarshal(url, Plugin.class);
+
+      plugin.setPath(path);
+      installedPlugins.add(plugin);
+    }
+    catch (Exception ex)
+    {
+      logger.error(ex.getMessage(), ex);
+    }
+  }
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  private ClassLoader getClassLoader()
+  {
+    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+
+    if (classLoader == null)
+    {
+      classLoader = DefaultPluginManager.class.getClassLoader();
+    }
+
+    return classLoader;
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** Field description */
+  private Set<Plugin> installedPlugins = new HashSet<Plugin>();
+}