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Public API for the Apache MyFaces Trinidad project
/*
* 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.myfaces.trinidad.change;
import java.util.HashMap;
import javax.el.ValueExpression;
import javax.faces.component.NamingContainer;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.el.ValueBinding;
import org.apache.myfaces.trinidad.logging.TrinidadLogger;
/**
* The base class for all ChangeManagers.
* A ChangeManager should manage accumulation of Changes and also
* take care of their persistence.
* @version $Name: $ ($Revision: adfrt/faces/adf-faces-api/src/main/java/oracle/adf/view/faces/change/ChangeManager.java#0 $) $Date: 10-nov-2005.19:09:58 $
*/
// WHENEVER A NEW METHOD IS ADDED TO THIS CLASS, REMEMBER TO ADD AN IMPLEMENTATION TO
// org.apache.myfaces.trinidad.change.ChangeManagerWrapper
public abstract class ChangeManager
{
public static void registerDocumentFactory(
String targetClassName,
String converterClassName)
{
if ((targetClassName == null) || (targetClassName.length() == 0))
throw new IllegalArgumentException(_LOG.getMessage(
"TARGET_CLASS_NAME_MUST_BE_PROVIDED"));
if ((converterClassName == null) || (converterClassName.length() == 0))
throw new IllegalArgumentException(_LOG.getMessage(
"CONVERTER_CLASS_NAME_MUST_BE_PROVIDED"));
synchronized (_CLASSNAME_TO_CONVERTER_NAME_MAP)
{
_CLASSNAME_TO_CONVERTER_NAME_MAP.put(targetClassName, converterClassName);
}
}
/**
* Use the conversion rules to attempt to retrieve the equivalent
* document change for a ComponentChange
* @param change to convert
*/
protected static DocumentChange createDocumentChange(
ComponentChange change)
{
// the supplied ComponentChange could implement DocumentChange
if (change instanceof DocumentChange)
{
return (DocumentChange)change;
}
Class changeClass = change.getClass();
Object converterObject = null;
DocumentChangeFactory converter = null;
synchronized (_CLASS_TO_CONVERTER_MAP)
{
converterObject = _CLASS_TO_CONVERTER_MAP.get(changeClass);
}
if (converterObject != null)
{
converter = (DocumentChangeFactory)converterObject;
}
else
{
String converterName = null;
synchronized (_CLASSNAME_TO_CONVERTER_NAME_MAP)
{
converterName =
_CLASSNAME_TO_CONVERTER_NAME_MAP.get(changeClass.getName());
}
if (converterName != null)
{
try
{
ClassLoader contextClassLoader =
Thread.currentThread().getContextClassLoader();
Class converterClass = contextClassLoader.loadClass(converterName);
if (DocumentChangeFactory.class.isAssignableFrom(converterClass))
{
converter = (DocumentChangeFactory)converterClass.newInstance();
synchronized (_CLASS_TO_CONVERTER_MAP)
{
_CLASS_TO_CONVERTER_MAP.put(changeClass, converter);
}
}
else
{
// log warning because class isn't correct type
_LOG.warning("CONVERSION_CLASS_TYPE", new Object[] {converterClass, DocumentChangeFactory.class});
}
}
catch (Throwable e)
{
_LOG.warning("UNABLE_INSTANTIATE_CONVERTERCLASS", converterName); // NOTRANS
_LOG.warning(e);
}
// if the registered converter class name doesn't work remove
// it from _CLASSNAME_TO_CONVERT_NAME_MAP
if (converter == null)
{
// this entry doesn't work, so remove it
_CLASSNAME_TO_CONVERTER_NAME_MAP.remove(converterName);
return null;
}
}
}
// return the converted object
if (converter != null)
return converter.convert(change);
return null;
}
/**
* Adds a ComponentChange to the current request for a specified component. Component changes
* cannot be added for stamped children of an UIXIterator.
*
* A DocumentChange will be automatically created and applied on the ChangeManager registered
* for this application if the following conditions are met:
* 1. The ChangeManager registered for the application supports document change persistence
* 2. DocumentChange corresponding to the supplied ComponentChange can be created with the help
* of any registered DocumentChangeFactory
* When such a DocumentChange is added, the ChangeManager registered for the application is
* notified by means of calling its documentChangeApplied() method. This is to give the
* registered ChangeManager an opportunity to take any necessary action. For example, Session
* based ChangeManager implementations may choose to remove the ComponentChange, if any added
* earlier. Custom ChangeManager implementations should notify likewise if it automatically
* creates and adds a DocumentChange.
*
* @throws IllegalArgumentException if any of the supplied parameters were to be null.
*
* @see DocumentChangeFactory
* @see #documentChangeApplied(FacesContext, UIComponent, ComponentChange
*/
public abstract void addComponentChange(
FacesContext facesContext,
UIComponent uiComponent,
ComponentChange change);
/**
* Replace an AttributeComponentChange if it's present.
*
* @param facesContext
* @param uiComponent
* @param attributeComponentChange
* @return the old change instance
*/
public AttributeComponentChange replaceAttributeChangeIfPresent(
FacesContext facesContext,
UIComponent uiComponent,
AttributeComponentChange attributeComponentChange)
{
_LOG.warning("Must be implemented by subclass");
return null;
}
/**
* Add a DocumentChange to this current request for a specified component.
* When called we will allow changes even if the component or its any ancestor
* is a stamped component by UIXIterator.
*
* @throws IllegalArgumentException if any of the supplied parameters were to
* be null.
*
* @deprecated use
* {@link ChangeManager#addDocumentChangeWithOutcome(javax.faces.context.FacesContext,javax.faces.component.UIComponent,org.apache.myfaces.trinidad.change.DocumentChange)}
* instead
*/
@Deprecated
public void addDocumentChange(
FacesContext facesContext,
UIComponent uiComponent,
DocumentChange change)
{
if (facesContext == null || uiComponent == null || change == null)
throw new IllegalArgumentException(_LOG.getMessage(
"CANNOT_ADD_CHANGE_WITH_FACECONTEXT_OR_UICOMPONENT_OR_NULL"));
}
/**
* Add a DocumentChange for a specified component, and return the outcome of adding the change.
*
* @param facesContext The FacesContext instance for the current request
* @param uiComponent The UIComponent instance for which the DocumentChange is to be added
* @param change The DocumentChange to be added
*
* @return The outcome of adding the document change
*
* @throws IllegalArgumentException if any of the supplied parameters were to
* be null.
*
* @see ChangeOutcome
*/
public ChangeOutcome addDocumentChangeWithOutcome(
FacesContext facesContext,
UIComponent uiComponent,
DocumentChange change)
{
addDocumentChange(facesContext, uiComponent, change);
return ChangeOutcome.UNKNOWN;
}
/**
* This method is called on the registered ChangeManager if a ChangeManager in its
* addComponentChange() implementation automatically creates an equivalent DocumentChange and
* applies the change. The registered ChangeManager may choose to take some action based on
* the outcome of applying the document change. For example, session based ChangeManager
* implementations may choose to remove any earlier added ComponentChange if an equivalent
* document change is now successfully applied
*
* @param component The target UIComponent instance for which the DocumentChange was
* applied
* @param componentChange The ComponentChange for which an equivalent DocumentChange was applied
*
* @return The outcome of handling this notification
*
* @throws IllegalArgumentException if the supplied ComponentChange is null. *
*/
public NotificationOutcome documentChangeApplied(
FacesContext facesContext,
UIComponent component,
ComponentChange componentChange)
{
if (componentChange == null)
throw new IllegalArgumentException("The supplied ComponentChange object is null");
return NotificationOutcome.NOT_HANDLED;
}
/**
* Applies all the ComponentChanges added so far for the current view.
* Developers should not need to call this method. Internal implementation
* will call it as the component tree is built and is ready to take changes.
* @param facesContext The FacesContext instance for the current request.
*/
public void applyComponentChangesForCurrentView(FacesContext facesContext)
{
throw new UnsupportedOperationException("Subclassers must implement");
}
/**
* Applies the ComponentChanges added so far for components underneath
* the specified NamingContainer.
* Developers should not need to call this method. Internal implementation
* will call it as the component tree is built and is ready to take changes.
* @param facesContext The FacesContext instance for the current request.
* @param root The NamingContainer that contains the component subtree
* to which ComponentChanges should be applied. If null, all changes are
* applied.
* @throws IllegalArgumentException if the root NamingContainer is not a
* UIComponent instance.
*/
public void applyComponentChangesForSubtree(
FacesContext facesContext,
NamingContainer root)
{
throw new UnsupportedOperationException("Subclassers must implement");
}
/**
* Apply non-cross-component changes to a component in its original location. This is typically
* only called by tags that need to ensure that a newly created component instance is
* as up-to-date as possible.
* @param context
* @param component Component to apply the simple changes to
*/
public void applySimpleComponentChanges(FacesContext context, UIComponent component)
{
throw new UnsupportedOperationException("Subclassers must implement");
}
/**
* Indicates the outcome of the attempt to apply a Change. Possible outcomes are:
* 1. UNKNOWN - We do not know if the change was applied or not
* 2. CHANGE_APPLIED - Change was successfully applied
* 3. CHANGE_NOT_APPLIED - There was a failure when applying the Change
*
* @see #addDocumentChangeWithOutcome(FacesContext,UIComponent,DocumentChange)
*/
public static enum ChangeOutcome
{
UNKNOWN,
CHANGE_APPLIED,
CHANGE_NOT_APPLIED;
private static final long serialVersionUID = 1L;
}
/**
* Indicates whether the notification was handled:
* 1. HANDLED - Notification was handled
* 2. NOT_HANDLED - Notification was not handled
*
* @see #documentChangeApplied(FacesContext, UIComponent, ComponentChange)
*/
public static enum NotificationOutcome
{
HANDLED,
NOT_HANDLED;
private static final long serialVersionUID = 1L;
}
private static class AttributeConverter extends DocumentChangeFactory
{
@Override
public DocumentChange convert(ComponentChange compChange)
{
if (compChange instanceof AttributeComponentChange)
{
AttributeComponentChange change = (AttributeComponentChange)compChange;
Object value = change.getAttributeValue();
// =-= bts TODO add registration of attribute converters
String valueString = null;
if ((value == null) ||
(value instanceof CharSequence) ||
(value instanceof Number) ||
(value instanceof Boolean))
{
valueString = (value != null)? value.toString() : null;
}
else if (value instanceof ValueExpression)
{
valueString = ((ValueExpression)value).getExpressionString();
}
else if (value instanceof ValueBinding)
{
valueString = ((ValueBinding)value).getExpressionString();
}
if (valueString != null)
return new AttributeDocumentChange(change.getAttributeName(),
valueString);
}
// no conversion possible
return null;
}
}
private static HashMap _CLASSNAME_TO_CONVERTER_NAME_MAP =
new HashMap();
private static HashMap, DocumentChangeFactory> _CLASS_TO_CONVERTER_MAP =
new HashMap, DocumentChangeFactory>();
static private final TrinidadLogger _LOG =
TrinidadLogger.createTrinidadLogger(ChangeManager.class);
static
{
// register the attribute converter
_CLASS_TO_CONVERTER_MAP.put(AttributeComponentChange.class,
new AttributeConverter());
}
}