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package com.sun.faces.facelets.tag.jsf.core;
import com.sun.faces.facelets.tag.TagHandlerImpl;
import com.sun.faces.facelets.tag.jsf.CompositeComponentTagHandler;
import com.sun.faces.facelets.util.ReflectionUtil;
import javax.el.ValueExpression;
import javax.faces.application.Resource;
import javax.faces.component.EditableValueHolder;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.event.AbortProcessingException;
import javax.faces.event.ValueChangeEvent;
import javax.faces.event.ValueChangeListener;
import javax.faces.view.EditableValueHolderAttachedObjectHandler;
import javax.faces.view.facelets.*;
import java.io.IOException;
import java.io.Serializable;
/**
* Register an ValueChangeListener instance on the UIComponent associated with
* the closest parent UIComponent custom action.<p/> See <a target="_new"
* href="http://java.sun.com/j2ee/javaserverfaces/1.1_01/docs/tlddocs/f/valueChangeListener.html">tag
* documentation</a>.
*
* @author Jacob Hookom
*/
public final class ValueChangeListenerHandler extends TagHandlerImpl implements EditableValueHolderAttachedObjectHandler {
private static class LazyValueChangeListener implements
ValueChangeListener,
Serializable {
private static final long serialVersionUID = 7613811124326963180L;
private final String type;
private final ValueExpression binding;
public LazyValueChangeListener(String type, ValueExpression binding) {
this.type = type;
this.binding = binding;
}
public void processValueChange(ValueChangeEvent event)
throws AbortProcessingException {
ValueChangeListener instance = null;
FacesContext faces = FacesContext.getCurrentInstance();
if (faces == null) {
return;
}
if (this.binding != null) {
instance = (ValueChangeListener) binding
.getValue(faces.getELContext());
}
if (instance == null && this.type != null) {
try {
instance = (ValueChangeListener) ReflectionUtil
.forName(this.type).newInstance();
} catch (Exception e) {
throw new AbortProcessingException(
"Couldn't Lazily instantiate ValueChangeListener",
e);
}
if (this.binding != null) {
binding.setValue(faces.getELContext(), instance);
}
}
if (instance != null) {
instance.processValueChange(event);
}
}
}
private final TagAttribute binding;
private final String listenerType;
private final TagAttribute typeAttribute;
public ValueChangeListenerHandler(TagConfig config) {
super(config);
this.binding = this.getAttribute("binding");
this.typeAttribute = this.getAttribute("type");
if (null != this.typeAttribute) {
String stringType = null;
if (!this.typeAttribute.isLiteral()) {
FacesContext context = FacesContext.getCurrentInstance();
FaceletContext ctx = (FaceletContext) context.getAttributes().get(FaceletContext.FACELET_CONTEXT_KEY);
stringType = (String) this.typeAttribute.getValueExpression(ctx, String.class).getValue(ctx);
} else {
stringType = this.typeAttribute.getValue();
}
checkType(stringType);
this.listenerType = stringType;
} else {
this.listenerType = null;
}
}
/**
* See taglib documentation.
*
* @see com.sun.faces.facelets.FaceletHandler#apply(com.sun.faces.facelets.FaceletContext, javax.faces.component.UIComponent)
*/
public void apply(FaceletContext ctx, UIComponent parent)
throws IOException {
// only process if it's been created
if (parent == null || !(ComponentHandler.isNew(parent))) {
return;
}
if (parent instanceof EditableValueHolder) {
applyAttachedObject(ctx.getFacesContext(), parent);
} else if (parent.getAttributes().containsKey(Resource.COMPONENT_RESOURCE_KEY)) {
// Allow the composite component to know about the target
// component.
CompositeComponentTagHandler.getAttachedObjectHandlers(parent).add(this);
} else {
throw new TagException(this.tag,
"Parent is not of type EditableValueHolder, type is: " + parent);
}
}
public void applyAttachedObject(FacesContext context, UIComponent parent) {
FaceletContext ctx = (FaceletContext) context.getAttributes().get(FaceletContext.FACELET_CONTEXT_KEY);
EditableValueHolder evh = (EditableValueHolder) parent;
ValueExpression b = null;
if (this.binding != null) {
b = this.binding.getValueExpression(ctx, ValueChangeListener.class);
}
ValueChangeListener listener = new LazyValueChangeListener(
this.listenerType, b);
evh.addValueChangeListener(listener);
}
public String getFor() {
String result = null;
TagAttribute attr = this.getAttribute("for");
if (null != attr) {
if (attr.isLiteral()) {
result = attr.getValue();
} else {
FacesContext context = FacesContext.getCurrentInstance();
FaceletContext ctx = (FaceletContext) context.getAttributes().get(FaceletContext.FACELET_CONTEXT_KEY);
result = (String)attr.getValueExpression(ctx, String.class).getValue(ctx);
}
}
return result;
}
private void checkType(String type) {
try {
ReflectionUtil.forName(type);
} catch (ClassNotFoundException e) {
throw new TagAttributeException(typeAttribute,
"Couldn't qualify ActionListener", e);
}
}
}