/*
* JBoss, Home of Professional Open Source.
* Copyright 2008, Red Hat Middleware LLC, and individual contributors
* as indicated by the @author tags. See the copyright.txt file in the
* distribution for a full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.iiop.rmi.marshal.strategy;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.rmi.UnexpectedException;
import javax.rmi.PortableRemoteObject;
import org.omg.CORBA.UserException;
import org.omg.CORBA.portable.IDLEntity;
import org.omg.CORBA_2_3.portable.InputStream;
import org.omg.CORBA_2_3.portable.OutputStream;
import org.jboss.iiop.rmi.marshal.CDRStream;
import org.jboss.iiop.rmi.marshal.CDRStreamReader;
import org.jboss.iiop.rmi.marshal.CDRStreamWriter;
/**
* An <code>StubStrategy</code> for a given method knows how to marshal
* the sequence of method parameters into a CDR output stream, how to unmarshal
* from a CDR input stream the return value of the method, and how to unmarshal
* from a CDR input stream an application exception thrown by the method.
*
* @author <a href="mailto:reverbel@ime.usp.br">Francisco Reverbel</a>
* @version $Revision: 81018 $
*/
public class StubStrategy
{
// Fields ------------------------------------------------------------------
/**
* Each <code>CDRStreamWriter</code> in the array marshals a method
* parameter.
*/
private CDRStreamWriter[] paramWriters;
/**
* List of exception classes.
*/
private List exceptionList;
/**
* Maps exception repository ids into ExceptionReader instances.
*/
private Map exceptionMap;
/**
* A <code>CDRStreamReader</code> that unmarshals the return value of the
* method.
*/
private CDRStreamReader retvalReader;
/**
* If this <code>StubStrategy</code> is for a method that returns a
* remote interface, this field contains the remote interface's
* <code>Class</code>. Otherwise it contains null.
*/
private Class retvalRemoteInterface;
// Static ------------------------------------------------------------------
/**
* Returns an <code>StubStrategy</code> for a method, given descriptions
* of the method parameters, exceptions, and return value. Parameter and
* return value descriptions are "marshaller abbreviated names".
*
* @param paramTypes a string array with marshaller abbreviated names for
* the method parameters
* @param excepIds a string array with the CORBA repository ids of the
* exceptions thrown by the method
* @param excepTypes a string array with the Java class names of the
* exceptions thrown by the method
* @param retvalType marshaller abbreaviated name for the return value of
* the method
* @param cl a <code>ClassLoader</code> to load value classes
* (if null, the current thread's context class loader
* will be used)
* @return an <code>StubStrategy</code> for the operation with the
* parameters, exceptions, and return value specified.
* @see org.jboss.iiop.marshal.CDRStream#abbrevFor(Class clz)
*/
public static StubStrategy forMethod(String[] paramTypes,
String[] excepIds,
String[] excepTypes,
String retvalType,
ClassLoader cl)
{
// This "factory method" exists just because I have found it easier
// to invoke a static method (rather than invoking operator new)
// from a stub class dynamically assembled by an instance of
// org.jboss.proxy.ProxyAssembler.
return new StubStrategy(paramTypes, excepIds,
excepTypes, retvalType, cl);
}
// Constructor -------------------------------------------------------------
/**
* Constructs an <code>StubStrategy</code> for a method, given
* descriptions of the method parameters, exceptions, and return value.
* Parameter and return value descriptions are "marshaller abbreviated
* names".
*
* @param paramTypes a string array with marshaller abbreviated names for
* the method parameters
* @param excepIds a string array with the CORBA repository ids of the
* exceptions thrown by the method
* @param excepTypes a string array with the Java class names of the
* exceptions thrown by the method
* @param retvalType marshaller abbreaviated name for the return value of
* the method
* @param cl a <code>ClassLoader</code> to load value classes
* (if null, the current thread's context class loader
* will be used)
* @see org.jboss.iiop.marshal.CDRStream#abbrevFor(Class clz)
*/
private StubStrategy(String[] paramTypes, String[] excepIds,
String[] excepTypes, String retvalType,
ClassLoader cl)
{
if (cl == null) {
cl = Thread.currentThread().getContextClassLoader();
}
// Initialize paramWriters
int len = paramTypes.length;
paramWriters = new CDRStreamWriter[len];
for (int i = 0; i < len; i++) {
paramWriters[i] = CDRStream.writerFor(paramTypes[i], cl);
}
// Initialize exception list and exception map
exceptionList = new ArrayList();
exceptionMap = new HashMap();
len = excepIds.length;
for (int i = 0; i < len; i++) {
try {
Class clz = cl.loadClass(excepTypes[i]);
exceptionList.add(clz);
ExceptionReader exceptionReader =
new ExceptionReader(clz, excepIds[i]);
exceptionMap.put(exceptionReader.getReposId(), exceptionReader);
}
catch (ClassNotFoundException e) {
throw new RuntimeException("Error loading class "
+ excepTypes[i] + ": " + e);
}
}
// Initialize retvalReader
retvalReader = CDRStream.readerFor(retvalType, cl);
// Initialize retvalRemoteInterface
if (retvalType.charAt(0) == 'R') {
try {
retvalRemoteInterface = cl.loadClass(retvalType.substring(1));
}
catch (ClassNotFoundException e) {
throw new RuntimeException("Error loading class "
+ retvalType.substring(1) + ": " + e);
}
}
}
// Public -----------------------------------------------------------------
/**
* Marshals the sequence of method parameters into an output stream.
*
* @param out a CDR output stream
* @param params an object array with the parameters.
*/
public void writeParams(OutputStream out, Object[] params)
{
int len = params.length;
if (len != paramWriters.length) {
throw new RuntimeException("Cannot marshal parameters: "
+ "unexpected number of parameters");
}
for (int i = 0; i < len; i++ ) {
paramWriters[i].write(out, params[i]);
}
}
/**
* Returns true if this <code>StubStrategy</code>'s method is non void.
*/
public boolean isNonVoid()
{
return (retvalReader != null);
}
/**
* Unmarshals from an input stream the return value of the method.
*
* @param in a CDR input stream
* @return a value unmarshaled from the stream.
*/
public Object readRetval(InputStream in)
{
return retvalReader.read(in);
}
/**
* Unmarshals from an input stream an exception thrown by the method.
*
* @param id the repository id of the exception to unmarshal
* @param in a CDR input stream
* @return an exception unmarshaled from the stream.
*/
public Exception readException(String id, InputStream in)
{
ExceptionReader exceptionReader = (ExceptionReader)exceptionMap.get(id);
if (exceptionReader == null) {
return new UnexpectedException(id);
}
else {
return exceptionReader.read(in);
}
}
/**
* Checks if a given <code>Throwable</code> instance corresponds to an
* exception declared by this <code>StubStrategy</code>'s method.
*
* @param t an exception class
* @return true if <code>t</code> is an instance of any of the
* exceptions declared by this <code>StubStrategy</code>'s
* method, false otherwise.
*/
public boolean isDeclaredException(Throwable t)
{
Iterator iterator = exceptionList.iterator();
while (iterator.hasNext()) {
if (((Class)iterator.next()).isInstance(t)) {
return true;
}
}
return false;
}
/**
* Converts the return value of a local invocation into the expected type.
* A conversion is needed if the return value is a remote interface
* (in this case <code>PortableRemoteObject.narrow()</code> must be called).
*
* @param obj the return value to be converted
* @return the converted value.
*/
public Object convertLocalRetval(Object obj)
{
if (retvalRemoteInterface == null)
return obj;
else
return PortableRemoteObject.narrow(obj, retvalRemoteInterface);
}
// Static inner class (private) --------------------------------------------
/**
* An <code>ExceptionReader</code> knows how to read exceptions of a given
* class from a CDR input stream.
*/
private static class ExceptionReader
{
/**
* The exception class.
*/
private Class clz;
/**
* The CORBA repository id of the exception class.
*/
private String reposId;
/*
* If the exception class corresponds to an IDL-defined exception, this
* field contains the read method of the associated helper class.
* A null value indicates that the exception class does not correspond
* to an IDL-defined exception.
*/
private java.lang.reflect.Method readMethod = null;
/**
* Constructs an <code>ExceptionReader</code> for a given exception
* class.
*/
ExceptionReader(Class clz, String reposId)
{
this.clz = clz;
if (IDLEntity.class.isAssignableFrom(clz)
&& UserException.class.isAssignableFrom(clz)) {
// This ExceptionReader corresponds to an IDL-defined exception
String helperClassName = clz.getName() + "Helper";
try {
Class helperClass =
clz.getClassLoader().loadClass(helperClassName);
Class[] paramTypes =
{ org.omg.CORBA.portable.InputStream.class };
readMethod = helperClass.getMethod("read", paramTypes);
// Ignore the reposId parameter and use the id
// returned by the IDL-generated helper class
java.lang.reflect.Method idMethod =
helperClass.getMethod("id", null);
this.reposId = (String)idMethod.invoke(null, null);
}
catch (ClassNotFoundException e) {
throw new RuntimeException("Error loading class "
+ helperClassName + ": " + e);
}
catch (NoSuchMethodException e) {
throw new RuntimeException("No read/id method in helper class "
+ helperClassName + ": " + e);
}
catch (IllegalAccessException e) {
throw new RuntimeException("Internal error: " + e);
}
catch (java.lang.reflect.InvocationTargetException e) {
throw new RuntimeException("Exception in call to "
+ helperClassName + ": "
+ e.getTargetException());
}
}
else {
// This ExceptionReader does not correspond to an IDL-defined
// exception: store the reposId parameter
this.reposId = reposId;
}
}
public String getReposId()
{
return reposId;
}
/**
* Reads an exception from a CDR input stream.
*/
public Exception read(InputStream in)
{
if (readMethod != null) {
try {
return (Exception)readMethod.invoke(null, new Object[] { in });
}
catch (IllegalAccessException e) {
throw new RuntimeException("Internal error: " + e);
}
catch (java.lang.reflect.InvocationTargetException e) {
throw new RuntimeException("Exception unmarshaling IDLEntity: "
+ e.getTargetException());
}
}
else {
in.read_string(); // read and discard the repository id
return (Exception)in.read_value(clz);
}
}
} // end of inner class ExceptionReader
}