/*
* Copyright (c) 1999-2004 Sourceforge JACOB Project.
* All rights reserved. Originator: Dan Adler (http://danadler.com).
* Get more information about JACOB at http://sourceforge.net/projects/jacob-project
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package com.jacob.activeX;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import com.jacob.com.InvocationProxy;
import com.jacob.com.NotImplementedException;
import com.jacob.com.Variant;
/**
* RELEASE 1.12 EXPERIMENTAL.
* <p>
* This class that lets event handlers receive events with all java objects as
* parameters. The standard Jacob event methods all accept an array of Variant
* objects. When using this class, you can set up your event methods as regular
* java methods with the correct number of parameters of the correct java type.
* This does NOT work for any event that wishes to accept a call back and modify
* the calling parameters to tell windows what to do. An example is when an
* event lets the receiver cancel the action by setting a boolean flag to false.
* The java objects cannot be modified and their values will not be passed back
* into the originating Variants even if they could be modified.
* <p>
* This class acts as a proxy between the windows event callback mechanism and
* the Java classes that are looking for events. It assumes that all of the Java
* classes that are looking for events implement methods with the same names as
* the windows events and that the implemented methods native java objects of
* the type and order that match the windows documentation. The methods can
* return void or a Variant that will be returned to the calling layer. All
* Event methods that will be recognized by InvocationProxyAllEvents have the
* signature
*
* <code> void eventMethodName(Object,Object...)</code> or
* <code> Object eventMethodName(Object,Object...)</code>
*/
public class ActiveXInvocationProxy extends InvocationProxy {
/*
* (non-Javadoc)
*
* @see com.jacob.com.InvocationProxy#invoke(java.lang.String,
* com.jacob.com.Variant[])
*/
@SuppressWarnings("unchecked")
public Variant invoke(String methodName, Variant targetParameters[]) {
Variant mVariantToBeReturned = null;
if (mTargetObject == null) {
// structured programming guidlines say this return should not be up
// here
return null;
}
Class targetClass = mTargetObject.getClass();
if (methodName == null) {
throw new IllegalArgumentException(
"InvocationProxy: missing method name");
}
if (targetParameters == null) {
throw new IllegalArgumentException(
"InvocationProxy: missing Variant parameters");
}
try {
Method targetMethod;
Object parametersAsJavaObjects[] = getParametersAsJavaObjects(targetParameters);
Class parametersAsJavaClasses[] = getParametersAsJavaClasses(parametersAsJavaObjects);
targetMethod = targetClass.getMethod(methodName,
parametersAsJavaClasses);
if (targetMethod != null) {
// protected classes can't be invoked against even if they
// let you grab the method. you could do
// targetMethod.setAccessible(true);
// but that should be stopped by the security manager
Object mReturnedByInvocation = null;
mReturnedByInvocation = targetMethod.invoke(mTargetObject,
parametersAsJavaObjects);
if (mReturnedByInvocation == null) {
mVariantToBeReturned = null;
} else if (!(mReturnedByInvocation instanceof Variant)) {
mVariantToBeReturned = new Variant(mReturnedByInvocation);
} else {
mVariantToBeReturned = (Variant) mReturnedByInvocation;
}
}
} catch (SecurityException e) {
// what causes this exception?
e.printStackTrace();
} catch (NoSuchMethodException e) {
// this happens whenever the listener doesn't implement all the
// methods
} catch (IllegalArgumentException e) {
// we can throw these inside the catch block so need to re-throw it
Exception oneWeShouldToss = new IllegalArgumentException(
"Unable to map parameters for method " + methodName + ": "
+ e.toString());
oneWeShouldToss.printStackTrace();
} catch (IllegalAccessException e) {
// can't access the method on the target instance for some reason
e.printStackTrace();
} catch (InvocationTargetException e) {
// invocation of target method failed
e.printStackTrace();
}
return mVariantToBeReturned;
}
/**
* creates a method signature compatible array of classes from an array of
* parameters
*
* @param parametersAsJavaObjects
* @return
*/
@SuppressWarnings("unchecked")
private Class[] getParametersAsJavaClasses(Object[] parametersAsJavaObjects) {
if (parametersAsJavaObjects == null) {
throw new IllegalArgumentException(
"This only works with an array of parameters");
}
int numParameters = parametersAsJavaObjects.length;
Class parametersAsJavaClasses[] = new Class[numParameters];
for (int parameterIndex = 0; parameterIndex < numParameters; parameterIndex++) {
Object oneParameterObject = parametersAsJavaObjects[parameterIndex];
if (oneParameterObject == null) {
parametersAsJavaClasses[parameterIndex] = null;
} else {
Class oneParameterClass = oneParameterObject.getClass();
parametersAsJavaClasses[parameterIndex] = oneParameterClass;
}
}
return parametersAsJavaClasses;
}
/**
* converts an array of Variants to their associated Java types
*
* @param targetParameters
* @return
*/
private Object[] getParametersAsJavaObjects(Variant[] targetParameters) {
if (targetParameters == null) {
throw new IllegalArgumentException(
"This only works with an array of parameters");
}
int numParameters = targetParameters.length;
Object parametersAsJavaObjects[] = new Object[numParameters];
for (int parameterIndex = 0; parameterIndex < numParameters; parameterIndex++) {
Variant oneParameterObject = targetParameters[parameterIndex];
if (oneParameterObject == null) {
parametersAsJavaObjects[parameterIndex] = null;
} else {
try {
parametersAsJavaObjects[parameterIndex] = oneParameterObject
.toJavaObject();
} catch (NotImplementedException nie) {
throw new IllegalArgumentException(
"Can't convert parameter " + parameterIndex
+ " type " + oneParameterObject.getvt()
+ " to java object: " + nie.getMessage());
}
}
}
return parametersAsJavaObjects;
}
}