Artifact
5c386eef44936eabf2d9055a044ea7dfc43b58e1:
/*
* BeanEventMgr.java --
*
* The Bean Event Manager: This class manages beans event
* handlers for a Tcl interpreter.
*
* Copyright (c) 1997 Sun Microsystems, Inc.
*
* See the file "license.terms" for information on usage and
* redistribution of this file, and for a DISCLAIMER OF ALL
* WARRANTIES.
*
* RCS: @(#) $Id: BeanEventMgr.java,v 1.1.1.1 1998/10/14 21:09:14 cvsadmin Exp $
*
*/
package tcl.lang;
import java.lang.reflect.*;
import java.util.*;
import java.beans.*;
/*
* This class manages beans event handlers for a Tcl interpreter:
* the event object stack, etc.
*/
class BeanEventMgr implements AssocData {
/*
* Stores all of the available event adaptor classes.
*/
private static Hashtable adaptorClsTab = new Hashtable();
/*
* The class loader for loading automatically generated event adaptor
* classes.
*/
private static AdaptorClassLoader adaptorLoader = new AdaptorClassLoader();
/*
* When a event handler is invoked, it is given a set of parameters
* (stored in an Object array.) The eventParamSetStack variable is
* used to store the parameter sets in a LIFO order when nested event
* handlers are invoked. Event parameters can be queried by the
* "java::event" command.
*/
Stack eventParamSetStack;
/*
*----------------------------------------------------------------------
*
* BeanEventMgr --
*
* Creates a new BeanEventMgr instance.
*
* Side effects:
* Member fields are initialized.
*
*----------------------------------------------------------------------
*/
private
BeanEventMgr()
{
eventParamSetStack = new Stack();
}
/*
*----------------------------------------------------------------------
*
* getBeanEventMgr --
*
* Returns the BeanEventMgr instance for the given interp. A new
* BeanEventMgr is created if no such BeanEventMgr exists for
* the interp.
*
* Results:
* The BeanEventMgr instance for the given interp.
*
* Side effects:
* A new BeanEventMgr may be created and registered as an
* AssocData in the given interp.
*
*----------------------------------------------------------------------
*/
static BeanEventMgr
getBeanEventMgr(
Interp interp) // Query the BeanEventMgr of this interp.
{
BeanEventMgr mgr = (BeanEventMgr)interp.getAssocData("tclBeanEvent");
if (mgr == null) {
mgr = new BeanEventMgr();
interp.setAssocData("tclBeanEvent", mgr);
}
return mgr;
}
/*
*----------------------------------------------------------------------
*
* pushEventParamSet --
*
* Pushes a set of event parameters to the top of the stack.
*
* Results:
* None.
*
* Side effects:
* The set of parameters are pushed to the top of the stack.
*
*----------------------------------------------------------------------
*/
void
pushEventParamSet(
BeanEventParamSet p) // The parameters to push to the top of the
// stack.
{
eventParamSetStack.push(p);
}
/*
*----------------------------------------------------------------------
*
* popEventParamSet --
*
* Pops the set of event parameters from the top of the stack.
*
* Results:
* None.
*
* Side effects:
* The size of the event parameter set stack is reduced by one.
*
*----------------------------------------------------------------------
*/
void
popEventParamSet()
throws
EmptyStackException // If the stack is already empty.
{
eventParamSetStack.pop();
}
/*
*----------------------------------------------------------------------
*
* peekEventParamSet --
*
* Returns the set of event parameters at the top of the stack.
*
* Results:
* If the event parameter stack is not empty, returns the set of
* parameters at the top of the stack. Otherwise, returns null.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
BeanEventParamSet
peekEventParamSet()
{
if (eventParamSetStack.size() == 0) {
return null;
} else {
return (BeanEventParamSet)eventParamSetStack.peek();
}
}
/*
*----------------------------------------------------------------------
*
* disposeAssocData --
*
* This method is called when the interpreter is destroyed or
* when Interp.deleteAssocData is called on a registered
* AssocData instance.
*
* Results:
* None.
*
* Side effects:
* Removes any bgerror's that haven't been reported.
*
*----------------------------------------------------------------------
*/
public void
disposeAssocData(
Interp interp) // The interpreter in which this AssocData
// instance is registered in.
{
eventParamSetStack = null;
}
/*
*----------------------------------------------------------------------
*
* setBinding --
*
* Sets the Tcl command to be executed when the given event fires
* in the reflectObj. A event adaptor is created when necessary.
*
* Results:
* None.
*
* Side effects:
* If the reflectObj doesn't yet have an EventAdaptor to handle
* the event, we will attempt to create it. This may cause an
* appropriate event adaptor class to be generated and loaded
* into the JVM; the EventAdaptor will be instantiated and
* registered as a listener of the given EventSet on the javaObj.
*
*----------------------------------------------------------------------
*/
void
setBinding(
Interp interp, // Current interpreter.
ReflectObject reflectObj, // The reflection object to create
// event binding for.
EventSetDescriptor eventSet, // The EventSet to bind to.
Method event, // Identifies a specific event in
// the EventSet to create a
// binding for.
TclObject command) // The command to execute when the
// given event fires.
throws
TclException // If the adaptor class cannot be
// generated, or if the adaptor
// cannot be instantiated.
{
EventAdaptor adaptor = null;
if (reflectObj.bindings == null) {
reflectObj.bindings = new Hashtable();
} else {
adaptor = (EventAdaptor)reflectObj.bindings.get(eventSet);
}
if (adaptor == null) {
Class lsnType = eventSet.getListenerType();
Class adaptorCls = (Class)adaptorClsTab.get(lsnType);
if (adaptorCls == null) {
/*
* We have never processed this type of EventSet yet. Generate
* an appropriate event adaptor class and load it
* into the JVM.
*/
adaptorCls = adaptorLoader.loadEventAdaptor(interp, eventSet);
adaptorClsTab.put(lsnType, adaptorCls);
}
try {
adaptor = (EventAdaptor)adaptorCls.newInstance();
} catch (InstantiationException e1) {
/*
* adaptor will remain null. This will trigger the
* exception later on.
*/
} catch (IllegalAccessException e2) {
/*
* adaptor will remain null. This will trigger the
* exception later on.
*/
}
if (adaptor == null) {
throw new TclException(interp,
"couldn't instantiate adaptor class for eventset \"" +
eventSet + "\"");
}
adaptor.init(interp, reflectObj.javaObj, eventSet);
/*
* Save the adaptor -- we only need a single adaptor for each
* EventSet to handle all possible events in this set.
*/
reflectObj.bindings.put(eventSet, adaptor);
}
if (command.toString().length() > 0) {
adaptor.setCallback(event.getName(), command);
} else {
/*
* The callback command is the empty string. This means remove
* any existing callback scripts. If no more callback scripts
* are registered in the adaptor, we'll remove it from the
* hashtable.
*/
if (adaptor.deleteCallback(event.getName()) == 0) {
reflectObj.bindings.remove(eventSet);
if (reflectObj.bindings.size() == 0) {
reflectObj.bindings = null;
}
}
}
}
/*
*----------------------------------------------------------------------
*
* getBinding --
*
* Queries the command to be executed when the given event fires
* in this object.
*
* Results:
* The command to execute when the event fires. null if no such
* command has be registered with the setBinding() method.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
TclObject
getBinding(
Interp interp, // Current interpreter.
ReflectObject reflectObj, // The reflection object to query.
EventSetDescriptor eventSet, // The EventSet to bind to.
Method event) // Identifies a specific event in
// the EventSet to query the
// binding for.
{
EventAdaptor adaptor = null;
if (reflectObj.bindings != null) {
adaptor = (EventAdaptor)reflectObj.bindings.get(eventSet);
}
if (adaptor == null) {
return null;
} else {
return adaptor.getCallback(event.getName());
}
}
/*
*----------------------------------------------------------------------
*
* getHandledEvents --
*
* Queries all the events that are currently handled by for this
* object.
*
* Results:
* A Tcl list of the events that are currently handled by for this
* object. The list is a valid empty Tcl list if this object
* handles no event.
*
* Side effects:
* None.
*
*----------------------------------------------------------------------
*/
TclObject
getHandledEvents(
ReflectObject reflectObj) // The reflection object to query.
{
TclObject list = TclList.newInstance();
if (reflectObj.bindings != null) {
for (Enumeration e = reflectObj.bindings.elements();
e.hasMoreElements(); ) {
EventAdaptor adaptor = (EventAdaptor)e.nextElement();
adaptor.getHandledEvents(list);
}
}
return list;
}
} // end BeanEventMgr