/*
* 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.ode.il;
import java.lang.reflect.Array;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import org.apache.axiom.om.OMAbstractFactory;
import org.apache.axiom.om.OMElement;
import org.apache.axiom.om.OMFactory;
import org.apache.axiom.om.impl.builder.StAXOMBuilder;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.ode.bpel.pmapi.ProcessInfoCustomizer;
import org.apache.xmlbeans.XmlObject;
import org.w3c.dom.Node;
/**
* Dynamic invocation handler for XML-based service; uses RPC message format conventions to dispatch
* invocation based on top-level element name (e.g. method name) and sub-elements (e.g. parameters).
*/
public class DynamicService<T> {
private final Log __log = LogFactory.getLog(getClass());
static final OMFactory OM = OMAbstractFactory.getOMFactory();
T _service;
Class<T> _clazz;
@SuppressWarnings("unchecked")
public DynamicService(T service) {
_clazz = (Class<T>) service.getClass();
_service = service;
}
public OMElement invoke(String operation, OMElement payload) {
if (__log.isDebugEnabled())
__log.debug("Invoke: operation "+operation+" on "+_clazz + ":\n" + payload);
String methodName = operation;
try {
Method invokedMethod = findMethod(methodName);
Object[] params = extractParams(invokedMethod, payload);
Object result = invokedMethod.invoke(_service, params);
OMElement response = null;
if (result != null) {
response = OM.createOMElement(new QName(payload.getNamespace().getNamespaceURI(), methodName+"Response"));
OMElement parts = convertToOM(result);
parts = stripNamespace(parts);
response.addChild(parts);
}
if (__log.isDebugEnabled()) {
__log.debug("Response: operation "+operation+" on "+_clazz + ":\n" + response);
}
return response;
} catch (IllegalAccessException e) {
throw new RuntimeException("Couldn't invoke method named " + methodName + " in management interface!", e);
} catch (InvocationTargetException e) {
throw new RuntimeException("Invocation of method " + methodName + " in management interface failed: " + e.getTargetException().getMessage(), e.getTargetException());
}
}
@SuppressWarnings("unchecked")
private Object[] extractParams(Method method, OMElement omElmt) {
Class<?>[] paramTypes = method.getParameterTypes();
Object[] params = new Object[method.getParameterTypes().length];
Iterator<OMElement> omChildren = (Iterator<OMElement>) omElmt.getChildElements();
int paramIdx = 0;
for (Class<?> paramClass : paramTypes) {
OMElement omchild = (OMElement) omChildren.next();
__log.debug("Extracting param " + paramClass + " from " + omchild);
params[paramIdx++] = convertFromOM(paramClass, omchild);
}
return params;
}
@SuppressWarnings("unchecked")
private static Object convertFromOM(Class<?> clazz, OMElement elmt) {
// Here comes the nasty code...
if (elmt == null || elmt.getText().length() == 0 && !elmt.getChildElements().hasNext())
return null;
else if (clazz.equals(String.class)) {
return elmt.getText();
} else if (clazz.equals(Boolean.class) || clazz.equals(Boolean.TYPE)) {
return (elmt.getText().equals("true") || elmt.getText().equals("yes")) ? Boolean.TRUE : Boolean.FALSE;
} else if (clazz.equals(QName.class)) {
// The getTextAsQName is buggy, it sometimes return the full text without extracting namespace
return OMUtils.getTextAsQName(elmt);
} else if (clazz.equals(ProcessInfoCustomizer.class)) {
return new ProcessInfoCustomizer(elmt.getText());
} else if (Node.class.isAssignableFrom(clazz)) {
return OMUtils.toDOM(elmt.getFirstElement());
} else if (clazz.equals(Long.TYPE) || clazz.equals(Long.class)) {
return Long.parseLong(elmt.getText());
} else if (clazz.equals(Integer.TYPE) || clazz.equals(Integer.class)) {
return Integer.parseInt(elmt.getText());
} else if (clazz.isArray()) {
ArrayList<Object> alist = new ArrayList<Object>();
Iterator<OMElement> children = elmt.getChildElements();
Class<?> targetClazz = clazz.getComponentType();
while (children.hasNext())
alist.add(parseType(targetClazz, ((OMElement)children.next()).getText()));
return alist.toArray((Object[]) Array.newInstance(targetClazz, alist.size()));
} else if (XmlObject.class.isAssignableFrom(clazz)) {
try {
Class beanFactory = Class.forName(clazz.getCanonicalName() + ".Factory");
return beanFactory.getMethod("parse", XMLStreamReader.class)
.invoke(elmt.getXMLStreamReaderWithoutCaching());
} catch (ClassNotFoundException e) {
throw new RuntimeException("Couldn't find class " + clazz.getCanonicalName() + ".Factory to instantiate xml bean", e);
} catch (IllegalAccessException e) {
throw new RuntimeException("Couldn't access class " + clazz.getCanonicalName() + ".Factory to instantiate xml bean", e);
} catch (InvocationTargetException e) {
throw new RuntimeException("Couldn't access xml bean parse method on class " + clazz.getCanonicalName() + ".Factory " +
"to instantiate xml bean", e);
} catch (NoSuchMethodException e) {
throw new RuntimeException("Couldn't find xml bean parse method on class " + clazz.getCanonicalName() + ".Factory " +
"to instantiate xml bean", e);
}
} else throw new RuntimeException("Couldn't use element " + elmt + " to obtain a management method parameter.");
}
@SuppressWarnings("unchecked")
private static OMElement convertToOM(Object obj) {
if (obj instanceof XmlObject) {
try {
return new StAXOMBuilder(((XmlObject)obj).newInputStream()).getDocumentElement();
} catch (XMLStreamException e) {
throw new RuntimeException("Couldn't serialize result to an outgoing messages.", e);
}
} else if (obj instanceof List) {
OMElement listElmt = OM.createOMElement("list", null);
for (Object stuff : ((List) obj)) {
OMElement stuffElmt = OM.createOMElement("element", null);
stuffElmt.setText(stuff.toString());
listElmt.addChild(stuffElmt);
}
return listElmt;
} else throw new RuntimeException("Couldn't convert object " + obj + " into a response element.");
}
@SuppressWarnings("unchecked")
private static OMElement stripNamespace(OMElement element) {
OMElement parent = OM.createOMElement(new QName("", element.getLocalName()));
Iterator<OMElement> iter = (Iterator<OMElement>) element.getChildElements();
while (iter.hasNext()) {
OMElement child = iter.next();
child = child.cloneOMElement();
parent.addChild(child);
}
return parent;
}
private Method findMethod(String methodName) {
for (Method method : _clazz.getMethods()) {
if (method.getName().equals(methodName)) return method;
}
throw new RuntimeException("Couldn't find any method named " + methodName + " in interface " + _clazz.getName());
}
private static Object parseType(Class<?> clazz, String str) {
if (clazz.equals(Integer.class)) return Integer.valueOf(str);
if (clazz.equals(Float.class)) return Integer.valueOf(str);
if (clazz.equals(String.class)) return str;
return null;
}
}