allow override of core classes

scm-webapp/src/main/java/sonia/scm/ClassOverride.java

@@ -0,0 +1,100 @@
+/**
+ * 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;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+
+/**
+ *
+ * @author Sebastian Sdorra
+ */
+@XmlAccessorType(XmlAccessType.FIELD)
+public class ClassOverride
+{
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  public Class<?> getBind()
+  {
+    return bind;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  public Class<?> getTo()
+  {
+    return to;
+  }
+
+  //~--- set methods ----------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param bind
+   */
+  public void setBind(Class<?> bind)
+  {
+    this.bind = bind;
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @param to
+   */
+  public void setTo(Class<?> to)
+  {
+    this.to = to;
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** Field description */
+  private Class<?> bind;
+
+  /** Field description */
+  private Class<?> to;
+}

scm-webapp/src/main/java/sonia/scm/ClassOverrides.java

@@ -0,0 +1,214 @@
+/**
+ * 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;
+
+//~--- non-JDK imports --------------------------------------------------------
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+//~--- JDK imports ------------------------------------------------------------
+
+import java.io.IOException;
+
+import java.net.URL;
+
+import java.util.ArrayList;
+import java.util.Enumeration;
+import java.util.Iterator;
+import java.util.List;
+
+import javax.xml.bind.JAXBContext;
+import javax.xml.bind.JAXBException;
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlElement;
+import javax.xml.bind.annotation.XmlRootElement;
+
+/**
+ *
+ * @author Sebastian Sdorra
+ */
+@XmlRootElement(name = "overrides")
+@XmlAccessorType(XmlAccessType.FIELD)
+public class ClassOverrides implements Iterable<ClassOverride>
+{
+
+  /** Field description */
+  public static final String OVERRIDE_PATH = "META-INF/scm/override.xml";
+
+  /**
+   * the logger for ClassOverrides
+   */
+  private static final Logger logger =
+    LoggerFactory.getLogger(ClassOverrides.class);
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   *
+   */
+  public static ClassOverrides findOverrides()
+  {
+    ClassOverrides overrides = new ClassOverrides();
+
+    try
+    {
+      Enumeration<URL> overridesEnm =
+        getClassLoader().getResources(OVERRIDE_PATH);
+      JAXBContext context = JAXBContext.newInstance(ClassOverrides.class);
+
+      while (overridesEnm.hasMoreElements())
+      {
+        URL overrideUrl = overridesEnm.nextElement();
+
+        try
+        {
+          ClassOverrides co =
+            (ClassOverrides) context.createUnmarshaller().unmarshal(
+                overrideUrl);
+        }
+        catch (Exception ex)
+        {
+          logger.error("could not load ".concat(overrideUrl.toExternalForm()),
+                       ex);
+        }
+      }
+    }
+    catch (IOException ex)
+    {
+      logger.error("could not load overrides", ex);
+    }
+    catch (JAXBException ex)
+    {
+      logger.error("could not create jaxb context for ClassOverrides", ex);
+    }
+
+    return overrides;
+  }
+  
+  public <T> Class<T> getOverride(Class<T> clazz){
+    Class<T> implementation = null;
+    for ( ClassOverride co : getOverrides() ){
+      if ( co.getBind().equals(clazz) ){
+        implementation = (Class<T>) co.getTo();
+      }
+    }
+    return implementation;
+  }
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  private static ClassLoader getClassLoader()
+  {
+    ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+
+    if (classLoader == null)
+    {
+      classLoader = ClassOverrides.class.getClassLoader();
+    }
+
+    return classLoader;
+  }
+
+  //~--- methods --------------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param overrides
+   */
+  public void append(ClassOverrides overrides)
+  {
+    getOverrides().addAll(overrides.getOverrides());
+  }
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  @Override
+  public Iterator<ClassOverride> iterator()
+  {
+    return getOverrides().iterator();
+  }
+
+  //~--- get methods ----------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @return
+   */
+  public List<ClassOverride> getOverrides()
+  {
+    if (overrides == null)
+    {
+      overrides = new ArrayList<ClassOverride>();
+    }
+
+    return overrides;
+  }
+
+  //~--- set methods ----------------------------------------------------------
+
+  /**
+   * Method description
+   *
+   *
+   * @param overrides
+   */
+  public void setOverrides(List<ClassOverride> overrides)
+  {
+    this.overrides = overrides;
+  }
+
+  //~--- fields ---------------------------------------------------------------
+
+  /** Field description */
+  @XmlElement(name = "override")
+  private List<ClassOverride> overrides;
+}

scm-webapp/src/main/java/sonia/scm/ScmServletModule.java

@@ -193,6 +193,7 @@ public class ScmServletModule extends ServletModule
   {
     this.pluginLoader = pluginLoader;
     this.bindExtProcessor = bindExtProcessor;
+    this.overrides = ClassOverrides.findOverrides();
   }
 
   //~--- methods --------------------------------------------------------------
@@ -219,13 +220,13 @@ public class ScmServletModule extends ServletModule
         DefaultRepositoryProvider.class).in(RequestScoped.class);
 
     // bind core
-    bind(StoreFactory.class).to(JAXBStoreFactory.class);
+    bind(StoreFactory.class, JAXBStoreFactory.class);
     bind(ScmConfiguration.class).toInstance(config);
     bind(PluginLoader.class).toInstance(pluginLoader);
-    bind(PluginManager.class).to(DefaultPluginManager.class);
+    bind(PluginManager.class, DefaultPluginManager.class);
     bind(KeyGenerator.class).toInstance(cu.getKeyGenerator());
     bind(CipherHandler.class).toInstance(cu.getCipherHandler());
-    bind(EncryptionHandler.class).to(MessageDigestEncryptionHandler.class);
+    bind(EncryptionHandler.class, MessageDigestEncryptionHandler.class);
     bindExtProcessor.bindExtensions(binder());
 
     Class<? extends FileSystem> fileSystem =
@@ -239,37 +240,37 @@ public class ScmServletModule extends ServletModule
     bind(FileSystem.class).to(fileSystem);
 
     // bind security stuff
-    bind(AuthenticationManager.class).to(ChainAuthenticatonManager.class);
+    bind(AuthenticationManager.class, ChainAuthenticatonManager.class);
     bind(LocalSecurityContextHolder.class);
     bind(WebSecurityContext.class).annotatedWith(Names.named("userSession")).to(
         BasicSecurityContext.class);
     bind(SecurityContext.class).toProvider(SecurityContextProvider.class);
     bind(WebSecurityContext.class).toProvider(SecurityContextProvider.class);
-    bind(AdministrationContext.class).to(DefaultAdministrationContext.class);
+    bind(AdministrationContext.class, DefaultAdministrationContext.class);
 
     // bind security cache
-    bind(CacheManager.class).to(EhCacheManager.class);
+    bind(CacheManager.class, EhCacheManager.class);
 
     // bind(RepositoryManager.class).annotatedWith(Undecorated.class).to(
     // BasicRepositoryManager.class);
-    bind(RepositoryManager.class).to(XmlRepositoryManager.class);
+    bind(RepositoryManager.class, XmlRepositoryManager.class);
-    bind(UserManager.class).to(XmlUserManager.class);
+    bind(UserManager.class, XmlUserManager.class);
-    bind(GroupManager.class).to(XmlGroupManager.class);
+    bind(GroupManager.class, XmlGroupManager.class);
-    bind(CGIExecutorFactory.class).to(DefaultCGIExecutorFactory.class);
+    bind(CGIExecutorFactory.class, DefaultCGIExecutorFactory.class);
     bind(ChangesetViewerUtil.class);
     bind(RepositoryBrowserUtil.class);
 
     // bind httpclient
-    bind(HttpClient.class).to(URLHttpClient.class);
+    bind(HttpClient.class, URLHttpClient.class);
 
     // bind resourcemanager
     if (context.getStage() == Stage.DEVELOPMENT)
     {
-      bind(ResourceManager.class).to(DevelopmentResourceManager.class);
+      bind(ResourceManager.class, DevelopmentResourceManager.class);
     }
     else
     {
-      bind(ResourceManager.class).to(DefaultResourceManager.class);
+      bind(ResourceManager.class, DefaultResourceManager.class);
     }
 
     // bind url provider staff
@@ -378,6 +379,37 @@ public class ScmServletModule extends ServletModule
     }
   }
 
+  /**
+   * Method description
+   *
+   *
+   * @param clazz
+   * @param defaultImplementation
+   * @param <T>
+   */
+  private <T> void bind(Class<T> clazz,
+                        Class<? extends T> defaultImplementation)
+  {
+    Class<? extends T> implementation = overrides.getOverride(clazz);
+
+    if (implementation != null)
+    {
+      logger.info("bind {} to override {}", clazz, implementation);
+    }
+    else
+    {
+      implementation = defaultImplementation;
+
+      if (logger.isDebugEnabled())
+      {
+        logger.debug("bind {} to defaul implementation {}", clazz,
+                     implementation);
+      }
+    }
+
+    bind(clazz).to(implementation);
+  }
+
   //~--- get methods ----------------------------------------------------------
 
   /**
@@ -440,6 +472,9 @@ public class ScmServletModule extends ServletModule
   /** Field description */
   private BindingExtensionProcessor bindExtProcessor;
 
+  /** Field description */
+  private ClassOverrides overrides;
+
   /** Field description */
   private PluginLoader pluginLoader;
 }