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The private implementation classes of the Apache MyFaces Core JSF-2.0 Implementation
/*
* 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.el.unified.resolver;
import java.beans.BeanInfo;
import java.beans.FeatureDescriptor;
import java.beans.PropertyDescriptor;
import java.lang.ref.WeakReference;
import java.util.Collection;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.WeakHashMap;
import javax.el.ELContext;
import javax.el.ELResolver;
import javax.el.ValueExpression;
import javax.faces.component.UIComponent;
import javax.faces.context.FacesContext;
import javax.faces.el.CompositeComponentExpressionHolder;
/**
* Composite component attribute EL resolver. See JSF spec, section 5.6.2.2.
*/
public final class CompositeComponentELResolver extends ELResolver
{
private static final String ATTRIBUTES_MAP = "attrs";
private static final String PARENT_COMPOSITE_COMPONENT = "parent";
private static final String COMPOSITE_COMPONENT_ATTRIBUTES_MAPS =
"org.apache.myfaces.COMPOSITE_COMPONENT_ATTRIBUTES_MAPS";
@Override
public Class getCommonPropertyType(ELContext context, Object base)
{
// Per the spec, return String.class.
return String.class;
}
@Override
public Iterator getFeatureDescriptors(ELContext context,
Object base)
{
// Per the spec, do nothing.
return null;
}
@Override
public Class getType(ELContext context, Object base, Object property)
{
// Per the spec, return null.
return null;
}
@Override
public Object getValue(ELContext context, Object base, Object property)
{
// Per the spec: base must not be null, an instance of UIComponent, and a composite
// component. Property must be a String.
if ((base != null) && (base instanceof UIComponent)
&& UIComponent.isCompositeComponent((UIComponent) base)
&& (property != null))
{
String propName = property.toString();
UIComponent baseComponent = (UIComponent) base;
if (propName.equals(ATTRIBUTES_MAP))
{
// Return a wrapped map that delegates all calls except get() and put().
context.setPropertyResolved(true);
return _getCompositeComponentAttributesMapWrapper(baseComponent, context);
}
else if (propName.equals(PARENT_COMPOSITE_COMPONENT))
{
// Return the parent.
context.setPropertyResolved(true);
return UIComponent.getCompositeComponentParent(baseComponent);
}
}
// Otherwise, spec says to do nothing (return null).
return null;
}
@SuppressWarnings("unchecked")
private Map _getCompositeComponentAttributesMapWrapper(
UIComponent baseComponent, ELContext elContext)
{
Map contextMap = (Map) facesContext(
elContext).getAttributes();
// We use a WeakHashMap>> to
// hold attribute map wrappers by two reasons:
//
// 1. The wrapper is used multiple times for a very short amount of time (in fact on current request).
// 2. The original attribute map has an inner reference to UIComponent, so we need to wrap it
// with WeakReference.
//
Map>> compositeComponentAttributesMaps =
(Map>>) contextMap
.get(COMPOSITE_COMPONENT_ATTRIBUTES_MAPS);
Map attributesMap = null;
WeakReference> weakReference;
if (compositeComponentAttributesMaps != null)
{
weakReference = compositeComponentAttributesMaps.get(baseComponent);
if (weakReference != null)
{
attributesMap = weakReference.get();
}
if (attributesMap == null)
{
//create a wrapper map
attributesMap = new CompositeComponentAttributesMapWrapper(
baseComponent);
compositeComponentAttributesMaps.put(baseComponent,
new WeakReference>(attributesMap));
}
}
else
{
//Create both required maps
attributesMap = new CompositeComponentAttributesMapWrapper(
baseComponent);
compositeComponentAttributesMaps = new WeakHashMap>>();
compositeComponentAttributesMaps.put(baseComponent,
new WeakReference>(attributesMap));
contextMap.put(COMPOSITE_COMPONENT_ATTRIBUTES_MAPS,
compositeComponentAttributesMaps);
}
return attributesMap;
}
// get the FacesContext from the ELContext
private static FacesContext facesContext(final ELContext context)
{
return (FacesContext)context.getContext(FacesContext.class);
}
@Override
public boolean isReadOnly(ELContext context, Object base, Object property)
{
// Per the spec, return true.
return true;
}
@Override
public void setValue(ELContext context, Object base, Object property,
Object value)
{
// Per the spec, do nothing.
}
// Wrapper map for composite component attributes. Follows spec, section 5.6.2.2, table 5-11.
private final class CompositeComponentAttributesMapWrapper
implements CompositeComponentExpressionHolder, Map
{
private final UIComponent _component;
private final BeanInfo _beanInfo;
private final Map _originalMap;
private final PropertyDescriptor [] _propertyDescriptors;
private CompositeComponentAttributesMapWrapper(UIComponent component)
{
this._component = component;
this._originalMap = component.getAttributes();
this._beanInfo = (BeanInfo) _originalMap.get(UIComponent.BEANINFO_KEY);
this._propertyDescriptors = _beanInfo.getPropertyDescriptors();
}
public ValueExpression getExpression(String name)
{
ValueExpression valueExpr = _component.getValueExpression(name);
return valueExpr;
}
public void clear()
{
_originalMap.clear();
}
public boolean containsKey(Object key)
{
return _originalMap.containsKey(key);
}
public boolean containsValue(Object value)
{
return _originalMap.containsValue(value);
}
public Set> entrySet()
{
return _originalMap.entrySet();
}
public Object get(Object key)
{
Object obj = _originalMap.get(key);
if (obj != null)
{
// _originalMap is a _ComponentAttributesMap and thus any
// ValueExpressions will be evaluated by the call to
// _originalMap.get(). The only case in which we really will
// get a ValueExpression here is when a ValueExpression itself
// is stored as an attribute. But in this case we really want to
// get the ValueExpression. So we don't have to evaluate possible
// ValueExpressions here, but can return obj directly.
return obj;
}
else
{
for (PropertyDescriptor attribute : _propertyDescriptors)
{
if (attribute.getName().equals(key))
{
obj = attribute.getValue("default");
break;
}
}
// We have to check for a ValueExpression and also evaluate it
// here, because in the PropertyDescriptor the default values are
// always stored as (Tag-)ValueExpressions.
if (obj != null && obj instanceof ValueExpression)
{
return ((ValueExpression) obj).getValue(FacesContext.getCurrentInstance().getELContext());
}
else
{
return obj;
}
}
}
public boolean isEmpty()
{
return _originalMap.isEmpty();
}
public Set keySet()
{
return _originalMap.keySet();
}
public Object put(String key, Object value)
{
ValueExpression valueExpression = _component.getValueExpression(key);
// Per the spec, if the result is a ValueExpression, call setValue().
if (valueExpression != null)
{
valueExpression.setValue(FacesContext.getCurrentInstance().getELContext(), value);
return null;
}
// Really this map is used to resolve ValueExpressions like
// #{cc.attrs.somekey}, so the value returned is not expected to be used,
// but is better to delegate to keep the semantic of this method.
return _originalMap.put(key, value);
}
public void putAll(Map m)
{
for (String key : m.keySet())
{
put(key, m.get(key));
}
}
public Object remove(Object key)
{
return _originalMap.remove(key);
}
public int size()
{
return _originalMap.size();
}
public Collection