1 files changed, 549 insertions, 0 deletions
diff --git a/java/management/client/src/main/java/org/apache/qpid/management/wsdm/capabilities/MBeanCapabilityBuilder.java b/java/management/client/src/main/java/org/apache/qpid/management/wsdm/capabilities/MBeanCapabilityBuilder.java
new file mode 100644
index 0000000000..ea67bdf9e1
--- /dev/null
+++ b/java/management/client/src/main/java/org/apache/qpid/management/wsdm/capabilities/MBeanCapabilityBuilder.java
@@ -0,0 +1,549 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF 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.apache.qpid.management.wsdm.capabilities;
+
+import javassist.CannotCompileException;
+import javassist.ClassClassPath;
+import javassist.ClassPool;
+import javassist.CtClass;
+import javassist.CtField;
+import javassist.CtMethod;
+import javassist.CtNewMethod;
+
+import javax.management.MBeanAttributeInfo;
+import javax.management.MBeanOperationInfo;
+import javax.management.MBeanParameterInfo;
+import javax.management.ObjectName;
+import javax.xml.namespace.QName;
+
+import org.apache.muse.core.Environment;
+import org.apache.qpid.management.Messages;
+import org.apache.qpid.management.Names;
+import org.apache.qpid.management.wsdm.common.EntityInstanceNotFoundFault;
+import org.apache.qpid.management.wsdm.common.MethodInvocationFault;
+import org.apache.qpid.management.wsdm.common.NoSuchAttributeFault;
+import org.apache.qpid.management.wsdm.common.QManFault;
+import org.apache.qpid.transport.util.Logger;
+
+/**
+ * Builder for capability class that will implements the interface 
+ * and the behaviour of the underlying JMX Entity.
+ * The product of this builder (capability class) will be used for create a new instance
+ * of the corresponding capability. It will be the "adapter" between WS-Resource and 
+ * JMX MBean.
+ * 
+ * @author Andrea Gazzarini
+ */
+public class MBeanCapabilityBuilder implements IArtifactBuilder{
+		
+	private final static String GET_PROPERTY_NAMES_METHOD_COMMON_PART = "public QName[] getPropertyNames() { return ";
+	private final static String GET_PROPERTY_NAMES_METHOD_WITH_ARRAY = GET_PROPERTY_NAMES_METHOD_COMMON_PART+" PROPERTIES;}";
+	private final static String GET_PROPERTY_NAMES_METHOD_WITH_EMPTY_ARRAY = GET_PROPERTY_NAMES_METHOD_COMMON_PART+" new QName[0];}";
+	private final static Logger LOGGER = Logger.get(MBeanCapabilityBuilder.class);
+	
+	/**
+	 * Handler interface definining operation needed to be 
+	 * peformed (by a concrete implementor) when the "endAttributes" 
+	 * director callback happens.
+	 * 
+	 * @author Andrea Gazzarini
+	 */
+	interface EndAttributesHandler {
+		
+		/**
+		 * Concrete implementor must define in this method what
+		 * needs to be done when the corresponding director callback
+		 * happens (@see {@link MBeanCapabilityBuilder#endAttributes()}
+		 * 
+		 * @throws BuilderException when a failure is raised inside the concrete implementation.
+		 */
+		void endAttributes() throws BuilderException;
+	};
+	
+	/**
+	 * This is the concrete implementation of the internal interface EndAttributesHandler
+	 * that is activated when this builder detects the presence of at least one property on the 
+	 * capability class.
+	 */
+	final EndAttributesHandler _atLeastThereIsOneProperty = new EndAttributesHandler() {
+
+		/**
+		 * Creates the QName array instance member and the corresponding 
+		 * accessor getPropertyNames().
+		 * 
+		 * @throws BuilderException when the member above cannot be added to the capability class.
+		 */
+		public void endAttributes() throws BuilderException
+		{
+			try 
+			{
+				_properties.deleteCharAt(_properties.length()-1);
+				_properties.append("};");
+
+				CtField properties = CtField.make(_properties.toString(), _capabilityClassDefinition);
+				
+				 _capabilityClassDefinition.addField(properties);
+				
+				CtMethod getPropertyNames = CtNewMethod.make(
+						GET_PROPERTY_NAMES_METHOD_WITH_ARRAY,
+						_capabilityClassDefinition);
+				_capabilityClassDefinition.addMethod(getPropertyNames);
+			} catch(Exception exception) 
+			{ 
+				throw new BuilderException(exception);
+			}			
+		}		
+	};
+	
+	/**
+	 * This is the concrete implementation of the internal interface EndAttributesHandler
+	 * that is activated when this builder detects that there are no properties defined for 
+	 * the capability class.
+	 */
+	final EndAttributesHandler _noPropertyHasBeenDefined= new EndAttributesHandler() 
+	{
+		/**
+		 * Creates the getPropertyNames() that simply returns an empty QName array.
+		 * 
+		 * @throws BuilderException when the member above cannot be added to the capability class.
+		 */
+		public void endAttributes() throws BuilderException
+		{
+			try 
+			{
+				CtMethod getPropertyNames = CtNewMethod.make(
+						GET_PROPERTY_NAMES_METHOD_WITH_EMPTY_ARRAY,
+						_capabilityClassDefinition);
+				_capabilityClassDefinition.addMethod(getPropertyNames);
+			} catch(Exception exception) 
+			{ 
+				throw new BuilderException(exception);
+			}			
+		}		
+	};
+	
+	/**
+	 * This is the active state for this builder when the requested class has never been
+	 * built.
+	 */
+	 IArtifactBuilder _classNotAvailable = new IArtifactBuilder()
+	{
+
+		/**
+		 * Build process begins.
+		 * The given object name is used to build a minimal definition of the product class.
+		 * 
+		 * @param objectName the name of the JMX entity.
+		 * @throws BuilderException when the initial definiton of the capability cannot be created.
+		 */
+		public void begin(ObjectName objectName) throws BuilderException
+		{
+			String className = objectName.getKeyProperty(Names.CLASS);
+			ClassPool pool = ClassPool.getDefault();
+			pool.insertClassPath(new ClassClassPath(MBeanCapabilityBuilder.class));
+			pool.importPackage(QName.class.getPackage().getName());
+			pool.importPackage(ObjectName.class.getPackage().getName());
+			pool.importPackage(QManFault.class.getPackage().getName());		
+			pool.importPackage(Names.class.getPackage().getName());
+			pool.importPackage(Result.class.getPackage().getName());
+			pool.importPackage(NoSuchAttributeFault.class.getPackage().getName());
+			pool.importPackage(EntityInstanceNotFoundFault.class.getPackage().getName());
+			pool.importPackage(MethodInvocationFault.class.getPackage().getName());
+			
+			_capabilityClassDefinition = pool.makeClass("org.apache.qpid.management.wsdm.capabilities."+className);
+			try 
+			{
+				_capabilityClassDefinition.setSuperclass(pool.get(MBeanCapability.class.getName()));
+			} catch(Exception exception) 
+			{
+				throw new BuilderException(exception);
+			} 
+		}
+
+		/**
+		 * Director callback. 
+		 * All attributes have been notified.
+		 * 
+		 * This builder is using this callback in order to create the initial 
+		 * properties QNames declaration.
+		 * 
+		 */
+		public void endAttributes() throws BuilderException
+		{
+			_endAttributeHandler.endAttributes();
+		}
+
+		@SuppressWarnings("unchecked")
+		public void endOperations() throws BuilderException
+		{
+			try 
+			{
+				_capabilityClass = _capabilityClassDefinition.toClass(
+						QManAdapterCapability.class.getClassLoader(),
+						QManAdapterCapability.class.getProtectionDomain());
+			} catch (Exception exception) 
+			{
+				throw new BuilderException(exception);
+			}
+		}
+
+		/**
+		 * Director callback. 
+		 * Attrbute metadata notification. With this callback the director informs this builder that the 
+		 * currently processed MBean has an attribute with the given metadata.
+		 * This builder uses this information in order to add a property and the corresponding accessors
+		 * to the capability class that is going to be built.
+		 * 
+		 *  @throws BuilderException bytecode manipulation / creation failure.
+		 */
+		public void onAttribute(MBeanAttributeInfo attribute) throws BuilderException
+		{
+			String name = attribute.getName();
+			String type = attribute.getType();
+			
+			try 
+			{
+				type = Class.forName(type).getCanonicalName();
+				
+				addPropertyMemberInstance(type, name);
+
+				String nameForAccessors = getNameForAccessors(name);
+				
+				if (attribute.isReadable()) 
+				{
+					String accessor = generateGetter(type, nameForAccessors,name);
+					CtMethod getter = CtNewMethod.make(accessor,_capabilityClassDefinition);
+					_capabilityClassDefinition.addMethod(getter);		
+					appendToPropertiesArray(name);
+
+					LOGGER.debug(
+							Messages.QMAN_200043_GENERATED_ACCESSOR_METHOD,
+							_objectName,
+							accessor);
+				}
+				
+				if (attribute.isWritable()) 
+				{
+					String accessor = generateSetter(type, nameForAccessors,name);
+					CtMethod setter = CtNewMethod.make(accessor,_capabilityClassDefinition);
+					_capabilityClassDefinition.addMethod(setter);					
+
+					LOGGER.debug(
+							Messages.QMAN_200043_GENERATED_ACCESSOR_METHOD,
+							_objectName,
+							accessor);
+				}		
+			} catch(Exception exception)
+			{
+				throw new BuilderException(exception);
+			}
+		}
+
+		public void onOperation(MBeanOperationInfo operation) throws BuilderException
+		{
+			StringBuilder method = new StringBuilder();
+			try 
+			{
+				method
+					.append("public Result ")
+					.append(operation.getName())
+					.append("( ");
+				
+				for (MBeanParameterInfo parameter: operation.getSignature())
+				{
+					method
+						.append(Class.forName(parameter.getType()).getCanonicalName())
+						.append(' ')
+						.append(parameter.getName())
+						.append(',');
+				}
+				
+				method.deleteCharAt(method.length()-1);
+				method.append(") throws EntityInstanceNotFoundFault, MethodInvocationFault,QManFault { return invoke(")
+					.append("\"").append(operation.getName()).append("\"")
+					.append(", new Object[]{ ");
+				
+				for (MBeanParameterInfo parameter: operation.getSignature())
+				{
+					method.append(parameter.getName())
+						.append(',');
+				}
+				
+				method.deleteCharAt(method.length()-1);			
+				method.append("}, new String[]{ ");
+				
+				for (MBeanParameterInfo parameter: operation.getSignature())
+				{
+					method
+						.append("\"")
+						.append(parameter.getType())
+						.append("\",");
+				}
+				method.deleteCharAt(method.length()-1);			
+				method.append("}); }");
+				
+				String methodAsString = method.toString();
+				methodAsString = methodAsString.replace("new Object[]{}","null");
+				methodAsString = methodAsString.replace("new String[]{}","null");
+				
+				CtMethod definition = CtNewMethod.make(methodAsString,_capabilityClassDefinition);
+				_capabilityClassDefinition.addMethod(definition);			
+			} catch(Exception exception)
+			{
+				throw new BuilderException(exception);
+			} finally {
+				if (LOGGER.isDebugEnabled())
+				{
+					LOGGER.debug(
+							Messages.QMAN_200044_GENERATED_METHOD, 
+							_objectName,
+							method.toString());
+				}
+			}
+		}
+		
+		public void setEnvironment(Environment environment)
+		{
+			// Nothing to do here...
+		}
+	};
+	
+	StringBuilder _properties = new StringBuilder("private static final QName[] PROPERTIES = new QName[]{ ");
+	private Class<MBeanCapability> _capabilityClass;
+	CtClass _capabilityClassDefinition;
+	EndAttributesHandler _endAttributeHandler = _noPropertyHasBeenDefined;
+	
+	private ObjectName _objectName;
+	
+	IArtifactBuilder _state;
+	
+	/**
+	 * Director callback. 
+	 * Attrbute metadata notification. With this callback the director informs this builder that the 
+	 * currently processed MBean has an attribute with the given metadata.
+	 * This builder uses this information in order to add a property and the corresponding accessors
+	 * to the capability class that is going to be built.
+	 * 
+	 *  @throws BuilderException bytecode manipulation / creation failure.
+	 */
+	public void onAttribute(MBeanAttributeInfo attribute) throws BuilderException 
+	{
+		_state.onAttribute(attribute);
+	}
+
+	/**
+	 * First callback : this method is called at the begin of the director process.
+	 * Contains builder initialization code.
+	 * 
+	 * @param objectName the name of the target JMX entity of this capability.
+	 * @throws BuilderException when the initialization fails.
+	 */
+	@SuppressWarnings("unchecked")
+	public void begin(ObjectName objectName) throws BuilderException 
+	{
+		try
+		{
+			this._objectName = objectName;
+			String className = objectName.getKeyProperty(Names.CLASS);
+			_capabilityClass = (Class<MBeanCapability>) Class.forName("org.apache.qpid.management.wsdm.capabilities."+className);
+			_state = new DummyCapabilityBuilder();
+		} catch (ClassNotFoundException exception)
+		{
+			_state = _classNotAvailable;
+		}
+	
+		_state.begin(objectName);
+	}
+	
+	/**
+	 * Director callback. 
+	 * Operation metadata notification. With this callback the director informs this builder that the 
+	 * currently processed MBean has an operation with the given metadata.
+	 * This builder uses this information in order to add a method to the capability class that is 
+	 * going to be built.
+	 * 
+	 * For example, let's suppose that an operation like that is detected on the MBean :
+	 * 
+	 * public void purge(int request)
+	 * 
+	 * then the capability will be enrichied with the following method :
+	 * 
+	 * public void purge(int request) throws QManFault {
+	 * 	invoke(
+	 * 		"purge",
+	 * 		new Object[]{request},
+	 * 		new String[]{int.class.getName()});
+	 * }
+	 * 
+	 *  @throws BuilderException bytecode manipulation / creation failure.
+	 */
+	public void onOperation(MBeanOperationInfo operation)  throws BuilderException
+	{
+		_state.onOperation(operation);
+	}
+
+	/**
+	 * Returns the capability class (the product of this builder). 
+	 * 
+	 * @return the capability class (the product of this builder).
+	 */
+	Class<MBeanCapability> getCapabilityClass() 
+	{
+		return _capabilityClass;
+	}
+
+	/**
+	 * Determines what needs to be done when all attributes 
+	 * metadata has been notified to this builder.
+	 * Capability class must have an array member with all defined 
+	 * properties and a getter method that returns it.
+	 * In this method those two members are declared (obviously only 
+	 * if this capability has at least one property).
+	 * 
+	 * @throws BuilderException when something fails during this phase.
+	 */
+	public void endAttributes() throws BuilderException
+	{
+		_state.endAttributes();
+	}
+
+	/**
+	 * Director callback. 
+	 * This method is notified when all operations metadata has been 
+	 * notified to this builder.
+	 * This is the place where the capability class is created, defined and loaded by the JVM.
+	 * 
+	 *  @throws BuilderException issues on this method are basically class loading related.
+	 */
+	@SuppressWarnings("unchecked")
+	public void endOperations() throws BuilderException
+	{
+		_state.endOperations();
+	}
+
+	/**
+	 * Injects the module environment on this builder.
+	 * 
+	 * @param environment the module environment.
+	 */
+	public void setEnvironment(Environment environment) 
+	{
+		// Nothing to do here...
+	}
+	
+	/**
+	 * Generates the get accessor method for the given property.
+	 *  
+	 * @param type the type of the property.
+	 * @param name the name of the property with the first letter capitalized.
+	 * @param plainName the plain name of the property.
+	 * @return the getter method (as a string).
+	 */
+	String generateGetter(String type, String name,String plainName) 
+	{
+		return new StringBuilder()
+			.append("public ")
+			.append(type)
+			.append(' ')
+			.append("get")
+			.append(name)
+			.append("() throws NoSuchAttributeFault,EntityInstanceNotFoundFault,QManFault { return (")
+			.append(type)
+			.append(") getAttribute(\"")
+			.append(plainName)
+			.append("\"); }")
+			.toString();
+	}
+
+	/**
+	 * Generates the set accessor method for the given property.
+	 *  
+	 * @param type the type of the property.
+	 * @param name the name of the property with the first letter capitalized.
+	 * @param plainName the plain name of the property.
+	 * @return the setter method (as a string).
+	 */
+	String generateSetter(String type, String name, String plainName) 
+	{
+		return new StringBuilder()
+			.append("public void ")
+			.append("set")
+			.append(name)
+			.append("(")
+			.append(type)
+			.append(" newValue) throws NoSuchAttributeFault,EntityInstanceNotFoundFault,QManFault {")
+			.append(" setAttribute(\"")
+			.append(plainName)
+			.append("\", newValue); }")
+			.toString();
+	}
+	
+	/**
+	 * Appends the given attribute name to the properties array declared as an
+	 * instance member of the capability class.
+	 * 
+	 * @param attributeName the name of the attribute.
+	 */
+	private void appendToPropertiesArray(String attributeName)
+	{
+		_properties.append("new QName(Names.NAMESPACE_URI, \"")
+		.append(attributeName)
+		.append("\", Names.PREFIX),");		
+
+		_endAttributeHandler = _atLeastThereIsOneProperty;
+	}
+	
+	/** 
+	 * Adds a new property member instance to the capability class.
+	 * 
+	 * @param type the type of the property.
+	 * @param name the name of the property.
+	 * @throws CannotCompileException  when the property cannot be added.
+	 */
+	private void addPropertyMemberInstance(String type, String name) throws CannotCompileException
+	{
+		StringBuilder buffer = new StringBuilder()
+			.append("private ")
+			.append(type)
+			.append(' ')
+			.append(name)
+			.append(';');
+
+		CtField field= CtField.make(buffer.toString(),_capabilityClassDefinition);
+		_capabilityClassDefinition.addField(field);		
+	}	
+	
+	/**
+	 * Returns a name that will be used in accessor methods.
+	 * That name will differ from the given one because the first letter will be capitalized.
+	 * For example, if the given name is "name" the return value will be "Name".
+	 * 
+	 * @param name the plain name of the attribute.
+	 * @return a capitalized version of the given name to be used in accessors.
+	 */
+	String getNameForAccessors(String name)
+	{
+		return 
+			Character.toUpperCase(name.charAt(0)) + 
+			name.substring(1);
+	}
+	
+}
+\ No newline at end of file