Added a FunctionLoader interfaces for loading functions and also added a basic implementation and an OSGi implementation.

project/pom.xml

@@ -565,6 +565,7 @@ pageTracker._trackPageview();
                         <Import-Package>${jclouds.osgi.import}</Import-Package>
                         <DynamicImport-Package>${jclouds.osgi.dynamic}</DynamicImport-Package>
                         <Fragment-Host>${jclouds.osgi.fragment}</Fragment-Host>
+                        <Bundle-Activator>${jclouds.osgi.activator}</Bundle-Activator>
                     </instructions>
                 </configuration>
             </plugin>

scriptbuilder/pom.xml

@@ -35,6 +35,7 @@
     <properties>
         <jclouds.test.listener />
 
+        <jclouds.osgi.activator>org.jclouds.scriptbuilder.osgi.Activator</jclouds.osgi.activator>
         <jclouds.osgi.export>org.jclouds.scriptbuilder*;version="${project.version}"</jclouds.osgi.export>
         <jclouds.osgi.import>org.jclouds*;version="${project.version}",*</jclouds.osgi.import>
     </properties>
@@ -52,6 +53,12 @@
             <version>1.46</version>
             <optional>true</optional>
         </dependency>
+        <dependency>
+            <groupId>org.osgi</groupId>
+            <artifactId>org.osgi.core</artifactId>
+            <version>4.2.0</version>
+            <scope>provided</scope>
+        </dependency>
     </dependencies>
 
 </project>

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/BasicFunctionLoader.java

@@ -0,0 +1,51 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.scriptbuilder;
+
+import com.google.common.base.Charsets;
+import com.google.common.io.CharStreams;
+import com.google.common.io.Resources;
+import org.jclouds.scriptbuilder.domain.OsFamily;
+import org.jclouds.scriptbuilder.domain.ShellToken;
+import org.jclouds.util.ClassLoadingUtils;
+
+import java.io.IOException;
+
+/**
+ * A {@link FunctionLoader} implementation which loads the target function from the classpath.
+ */
+public class BasicFunctionLoader implements FunctionLoader {
+
+  /**
+   * Loads a function from the classpath using the current or the Thread Context Class Loader.
+   * @param function The function name to load.
+   * @param family   This operating system family of the function.
+   * @return         The function as {@link String}
+   * @throws FunctionNotFoundException
+   */
+  @Override
+  public String loadFunction(String function, OsFamily family) throws FunctionNotFoundException {
+    try {
+      return CharStreams.toString(Resources.newReaderSupplier(ClassLoadingUtils.loadResource(BasicFunctionLoader.class, String
+              .format("/functions/%s.%s", function, ShellToken.SH.to(family))), Charsets.UTF_8));
+    } catch (IOException e) {
+      throw new FunctionNotFoundException(function, family, e);
+    }
+  }
+}

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/FunctionLoader.java

@@ -0,0 +1,37 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.scriptbuilder;
+
+import org.jclouds.scriptbuilder.domain.OsFamily;
+
+/**
+ * A function loader interface.
+ */
+public interface FunctionLoader {
+
+  /**
+   * Loads a function and returns it as {@link String}.
+   * @param function The function name to load.
+   * @param family   This operating system family of the function.
+   * @return         The function as {@link String}.
+   * @throws FunctionNotFoundException
+   */
+  public String loadFunction(String function, OsFamily family) throws FunctionNotFoundException;
+
+}

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/FunctionNotFoundException.java

@@ -0,0 +1,36 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.scriptbuilder;
+
+import org.jclouds.scriptbuilder.domain.OsFamily;
+
+public class FunctionNotFoundException extends RuntimeException {
+  /**
+   * The serialVersionUID
+   */
+  private static final long serialVersionUID = 1L;
+
+  public FunctionNotFoundException(String functionName, OsFamily family) {
+    super("function: " + functionName + " not found for famiy: " + family);
+  }
+
+  public FunctionNotFoundException(String functionName, OsFamily family, Throwable cause) {
+    super("function: " + functionName + " not found for famiy: " + family, cause);
+  }
+}

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/osgi/Activator.java

@@ -0,0 +1,76 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.scriptbuilder.osgi;
+
+import org.jclouds.scriptbuilder.util.Utils;
+import org.osgi.framework.BundleActivator;
+import org.osgi.framework.BundleContext;
+
+public class Activator implements BundleActivator {
+
+  BundleFunctionLoader functionLoader;
+
+  /**
+   * Called when this bundle is started so the Framework can perform the
+   * bundle-specific activities necessary to start this bundle. This method
+   * can be used to register services or to allocate any resources that this
+   * bundle needs.
+   * <p/>
+   * <p/>
+   * This method must complete and return to its caller in a timely manner.
+   *
+   * @param context The execution context of the bundle being started.
+   * @throws Exception If this method throws an exception, this
+   *                   bundle is marked as stopped and the Framework will remove this
+   *                   bundle's listeners, unregister all services registered by this
+   *                   bundle, and release all services used by this bundle.
+   */
+  @Override
+  public void start(BundleContext context) throws Exception {
+    functionLoader = new BundleFunctionLoader(context);
+    functionLoader.start();
+    Utils.functionLoader = new ServiceFunctionLoader(context);
+
+  }
+
+  /**
+   * Called when this bundle is stopped so the Framework can perform the
+   * bundle-specific activities necessary to stop the bundle. In general, this
+   * method should undo the work that the <code>BundleActivator.start</code>
+   * method started. There should be no active threads that were started by
+   * this bundle when this bundle returns. A stopped bundle must not call any
+   * Framework objects.
+   * <p/>
+   * <p/>
+   * This method must complete and return to its caller in a timely manner.
+   *
+   * @param context The execution context of the bundle being stopped.
+   * @throws Exception If this method throws an exception, the
+   *                   bundle is still marked as stopped, and the Framework will remove
+   *                   the bundle's listeners, unregister all services registered by the
+   *                   bundle, and release all services used by the bundle.
+   */
+  @Override
+  public void stop(BundleContext context) throws Exception {
+    if (functionLoader != null) {
+      functionLoader.stop();
+      functionLoader = null;
+    }
+  }
+}

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/osgi/BundleFunctionLoader.java

@@ -0,0 +1,105 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.scriptbuilder.osgi;
+
+import com.google.common.base.Charsets;
+import com.google.common.io.CharStreams;
+import com.google.common.io.Resources;
+import org.jclouds.scriptbuilder.FunctionLoader;
+import org.jclouds.scriptbuilder.FunctionNotFoundException;
+import org.jclouds.scriptbuilder.domain.OsFamily;
+import org.jclouds.scriptbuilder.domain.ShellToken;
+import org.osgi.framework.Bundle;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.ServiceRegistration;
+
+import java.io.IOException;
+import java.net.URL;
+import java.util.Enumeration;
+import java.util.Properties;
+
+/**
+ * A {@link FunctionLoader} which searches for functions in the {@link Bundle} resources.
+ */
+public class BundleFunctionLoader implements FunctionLoader {
+
+  private final BundleContext bundleContext;
+  private ServiceRegistration registration;
+
+  /**
+   * Constructor
+   *
+   * @param bundleContext
+   */
+  public BundleFunctionLoader(BundleContext bundleContext) {
+    this.bundleContext = bundleContext;
+  }
+
+  /**
+   * Starts the loader.
+   * Looks up for {@link Bundle} resources and registers itself in the service registry.
+   * It adds a property to the service which advertise all the functions found in the local resources.
+   */
+  public void start() {
+    Bundle bundle = bundleContext.getBundle();
+    Enumeration entries = bundle.findEntries("/functions/", "*.*", false);
+    StringBuilder sb = new StringBuilder();
+    while (entries.hasMoreElements()) {
+      URL url = (URL) entries.nextElement();
+      String function = url.getFile();
+      sb.append(function);
+      if (entries.hasMoreElements()) {
+        sb.append(" ");
+      }
+    }
+    String functions = sb.toString();
+    registerFunction(functions);
+  }
+
+  /**
+   * Unregisters itself from the service registry.
+   */
+  public void stop() {
+    registration.unregister();
+  }
+
+
+  /**
+   * Loads the function from the {@link Bundle} resources.
+   * @param function The function name to load.
+   * @param family   This operating system family of the function.
+   * @return
+   * @throws FunctionNotFoundException
+   */
+  @Override
+  public String loadFunction(String function, OsFamily family) throws FunctionNotFoundException {
+    try {
+      return CharStreams.toString(Resources.newReaderSupplier(bundleContext.getBundle().getResource(String.format("/functions/%s.%s", function, ShellToken.SH.to(family))), Charsets.UTF_8));
+    } catch (IOException e) {
+      throw new FunctionNotFoundException(function, family, e);
+    }
+  }
+
+  private void registerFunction(String functions) {
+    Properties properties = new Properties();
+    properties.put("function",functions);
+    registration = bundleContext.registerService(FunctionLoader.class.getName(), this,properties);
+  }
+
+}

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/osgi/ServiceFunctionLoader.java

@@ -0,0 +1,73 @@
+/**
+ * Licensed to jclouds, Inc. (jclouds) under one or more
+ * contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  jclouds licenses this file
+ * to you 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 org.jclouds.scriptbuilder.osgi;
+
+import com.google.common.base.Strings;
+import org.jclouds.scriptbuilder.FunctionLoader;
+import org.jclouds.scriptbuilder.FunctionNotFoundException;
+import org.jclouds.scriptbuilder.domain.OsFamily;
+import org.jclouds.scriptbuilder.domain.ShellToken;
+import org.osgi.framework.BundleContext;
+import org.osgi.framework.InvalidSyntaxException;
+import org.osgi.framework.ServiceReference;
+
+/**
+ * A {@link FunctionLoader} implementation which delegates loading to the OSGi service registry.
+ */
+public class ServiceFunctionLoader implements FunctionLoader {
+
+  private final BundleContext bundleContext;
+
+  public ServiceFunctionLoader(BundleContext bundleContext) {
+    this.bundleContext = bundleContext;
+  }
+
+  /**
+   * Looks up the service registry for an applicable {@link FunctionLoader} and delegates to it.
+   * @param function The function name to load.
+   * @param family   This operating system family of the function.
+   * @return         The function as {@link String}
+   * @throws FunctionNotFoundException
+   */
+  @Override
+  public String loadFunction(String function, OsFamily family) throws FunctionNotFoundException {
+    ServiceReference[] references = null;
+    String filter = String.format("(function=*%s.%s*)", function, ShellToken.SH.to(family));
+    try {
+      references = bundleContext.getServiceReferences(FunctionLoader.class.getName(), filter);
+      for (ServiceReference reference : references) {
+        FunctionLoader loader = (FunctionLoader) bundleContext.getService(reference);
+        String f = loader.loadFunction(function, family);
+        if (!Strings.isNullOrEmpty(f)) {
+          return f;
+        }
+      }
+    } catch (InvalidSyntaxException e) {
+      throw new FunctionNotFoundException(function, family, e);
+    } finally {
+      if (references != null) {
+        for (ServiceReference reference : references) {
+          bundleContext.ungetService(reference);
+        }
+      }
+    }
+    throw new FunctionNotFoundException(function, family);
+  }
+
+}

scriptbuilder/src/main/java/org/jclouds/scriptbuilder/util/Utils.java

@@ -18,25 +18,22 @@
  */
 package org.jclouds.scriptbuilder.util;
 
-import java.io.IOException;
 import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import org.jclouds.scriptbuilder.BasicFunctionLoader;
+import org.jclouds.scriptbuilder.FunctionLoader;
 import org.jclouds.scriptbuilder.domain.OsFamily;
 import org.jclouds.scriptbuilder.domain.ShellToken;
-import org.jclouds.util.ClassLoadingUtils;
 
 import com.google.common.base.CaseFormat;
-import com.google.common.base.Charsets;
 import com.google.common.base.Function;
 import com.google.common.base.Joiner;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Iterables;
-import com.google.common.io.CharStreams;
-import com.google.common.io.Resources;
 
 /**
  * Utilities used to build init scripts.
@@ -47,6 +44,8 @@ public class Utils {
 
    public static final LowerCamelToUpperUnderscore FUNCTION_LOWER_CAMEL_TO_UPPER_UNDERSCORE = new LowerCamelToUpperUnderscore();
 
+   public static FunctionLoader functionLoader = new BasicFunctionLoader();
+
    public static final class LowerCamelToUpperUnderscore implements Function<String, String> {
       @Override
       public String apply(String from) {
@@ -135,30 +134,12 @@ public class Utils {
    }
 
    public static String writeFunctionFromResource(String function, OsFamily family) {
-      try {
-         String toReturn = CharStreams.toString(Resources.newReaderSupplier(ClassLoadingUtils.loadResource(Utils.class, String
-                 .format("/functions/%s.%s", function, ShellToken.SH.to(family))), Charsets.UTF_8));
+         String toReturn = functionLoader.loadFunction(function,family);
          String lf = ShellToken.LF.to(family);
          return toReturn.endsWith(lf) ? toReturn : new StringBuilder(toReturn).append(lf).toString();
-      } catch (IOException e) {
-         throw new FunctionNotFoundException(function, family, e);
-      }
    }
 
-   public static class FunctionNotFoundException extends RuntimeException {
-      /** The serialVersionUID */
-      private static final long serialVersionUID = 1L;
-
-      public FunctionNotFoundException(String functionName, OsFamily family) {
-         super("function: " + functionName + " not found for famiy: " + family);
-      }
-
-      public FunctionNotFoundException(String functionName, OsFamily family, Throwable cause) {
-         super("function: " + functionName + " not found for famiy: " + family, cause);
-      }
-   }
-
-   public static String writeFunction(String function, String source) {
+  public static String writeFunction(String function, String source) {
       return String.format("{fncl}%s{fncr}%s{fnce}", function, source.replaceAll("^", "   "));
    }