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Private implementation of the Apache MyFaces Trinidad project
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/*
* 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.trinidadinternal.skin;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.MissingResourceException;
import org.apache.myfaces.trinidad.context.LocaleContext;
import org.apache.myfaces.trinidad.context.RenderingContext;
import org.apache.myfaces.trinidad.logging.TrinidadLogger;
import org.apache.myfaces.trinidad.skin.Icon;
import org.apache.myfaces.trinidad.skin.Skin;
import org.apache.myfaces.trinidad.skin.SkinAddition;
import org.apache.myfaces.trinidad.skin.SkinVersion;
import org.apache.myfaces.trinidadinternal.renderkit.core.CoreRenderingContext;
import org.apache.myfaces.trinidadinternal.skin.icon.NullIcon;
import org.apache.myfaces.trinidadinternal.skin.icon.ReferenceIcon;
import org.apache.myfaces.trinidadinternal.style.StyleContext;
import org.apache.myfaces.trinidadinternal.style.StyleProvider;
import org.apache.myfaces.trinidadinternal.style.xml.parse.StyleSheetDocument;
/**
* This is a Skin decorator which is used to store request-specific
* skin state. For example, the set of icons to use varies from
* request to request, eg. based on the browser/platform. We cannot
* store such request-specific state on our shared Skin instances.
* Instead, SkinFactoryImpl wraps shared Skin instances in RequestSkinWrappers
* so that request-specific state can be stored locally in the wrapper.
*
* Currently, the request-specific state for a skin is the icon map and the skin property map.
* They are retrieved from the StyleProvider one time per request and stored here.
* @see org.apache.myfaces.trinidadinternal.style.cache.FileSystemStyleCache
*/
public class RequestSkinWrapper extends Skin implements DocumentProviderSkin
{
// An alternate implementation strategy would be to enhance SkinImpl.getIcon()
// to serve up the request/context-specific Icons directly, rather than do so
// via a wrapper Skin class. There are two issues with the SkinImpl-based
// solution:
//
// 1. SkinImpl.getIcon() needs access to the StyleContext in order to retrieve
// the request/context-specific Icon map. However, Skin.getIcon() does not
// get take a StyleContext. We could change the Skin.getIcon() API to take
// a StyleContext, but since this is a public API we would prefer a solution
// which does not involve an API change. Alternatively, SkinImpl.getIcon()
// could get at the StyleContext by retrieving the RenderingContext, casting
// to CoreRenderingContext, and calling CoreRenderingContext.getStyleContext().
// However, that adds overhead to the SkinImpl.getIcon() implementation
// (mainly just a ThreadLocal look up, which isn't the end of the world,
// but nonetheless would prefer to avoid if possible).
//
// 2. Calls to registerIcon() need to behave differently depending on whether
// the Icon is being registered at Skin initialization time, or at
// request-time.
//
// At Skin initialization time, we simply want to register the Icon on the
// Skin instance itself, since such Icons are global to the Skin. However,
// we also use registerIcon() to register request-specific icon - for example,
// see CoreRenderingContext.getIcon()'s handling of rtl icons. We cannot
// register these request-specific Icons on the Skin as the Skin is reused
// across requests. Instead we want to register request-specific Icons on
// the request-specific Icon map.
//
// In order to deal with #2, we could have SkinImpl behave differently
// depending on whether it is at initialization time or request time. However,
// this is awkward and more cleanly solved via the request-specific wrapper
// approach.
public RequestSkinWrapper(Skin wrappedSkin)
{
_skin = wrappedSkin;
}
/**
* Returns the Skin that is wrapped by this request-specific
* wrapper skin.
*/
public Skin getWrappedSkin()
{
return _skin;
}
@Override
public String getId()
{
return _skin.getId();
}
@Override
public String getFamily()
{
return _skin.getFamily();
}
@Override
public SkinVersion getVersion()
{
return _skin.getVersion();
}
@Override
public String getRenderKitId()
{
return _skin.getRenderKitId();
}
@Override
public String getStyleSheetDocumentId(RenderingContext arc)
{
return _skin.getStyleSheetDocumentId(arc);
}
@Override
public Map getStyleClassMap(RenderingContext arc)
{
return _skin.getStyleClassMap(arc);
}
@Override
public String getStyleSheetName()
{
return _skin.getStyleSheetName();
}
@Override
public String getTranslatedString(
LocaleContext lContext,
String key
) throws MissingResourceException
{
return _skin.getTranslatedString(lContext, key);
}
@Override
public Object getTranslatedValue(
LocaleContext lContext,
String key
) throws MissingResourceException
{
return _skin.getTranslatedValue(lContext, key);
}
@Override
public Icon getIcon(String iconName)
{
return this.getIcon(iconName, true);
}
@Override
public Icon getIcon(
String iconName,
boolean resolveIcon)
{
// We look for the icon in two places:
//
// 1. In the icon map provided by the StyleProvider.
// The StyleProvider serves up icons that are
// specific to this particular request, including
// agent-specific icons.
// 2. In the wrapped Skin instance. Any Icons that are
// manually registered via a call to registerIcon()
// will be stored in the wrapped skin.
// Note: no synchronization needed since we are in a
// a request-specific object.
Map icons = _getRequestIcons();
assert(icons != null);
Icon icon = icons.get(iconName);
if (icon == null)
{
icon = _skin.getIcon(iconName, false);
// Resolve ReferenceIcons if necessary
if (resolveIcon)
{
if (icon instanceof ReferenceIcon)
icon = SkinUtils.resolveReferenceIcon(this, (ReferenceIcon)icon);
// We ended up having to do two lookups for icons
// which are not available in the StyleProvider
// icon map. To avoid having to do two lookups
// the next time this icon is requested, we promote
// the icon up from the wrapped skin into the
// StyleProvider icon map. Note that we only cache
// resolved icons in this way - we don't want to
// pollute our cache with unresolved ReferenceIcons.
registerIcon(iconName, icon);
}
}
return (icon == _NULL_ICON) ? null : icon;
}
@Override
public void registerIcon(
String iconName,
Icon icon)
{
// registerIcon() is called on a RequestSkinWrapper
// in two cases:
//
// 1. CoreRenderingContext.getIcon() contains special handling
// for icons when the reading direction is right-to-left. If a
// rtl variant of the icon is not available, CoreRenderingContext
// will look up the non-directional version of the icon and register
// that under the rtl name to avoid repeated lookups.
//
// 2. RequestSkinWrapper.getIcon() calls registerIcon() to register
// icons which were not found in the StyleProvider's icon map. This
// also is done as a performance optimization - to repeatedly looking
// up icons first in the StyleProvider icon map and then in the
// wrapped skin.
//
// In both of these cases storing the missing icon in the StyleProvider
// icon map is safe/appropriate, since lookups with the same set of
// StyleContext properties would return the same results. By storing
// the result in the StyleProvider icon map, we short-circuit, avoiding
// redundant work.
Map icons = _getRequestIcons();
if (icons != _NULL_ICONS)
icons.put(iconName, (icon == null) ? _NULL_ICON : icon);
}
@Override
public Object getProperty(Object key)
{
// We look for the skin properties in two places:
//
// 1. In the skin property map provided by the StyleProvider (see _getRequestSkinProperties).
// The StyleProvider serves up skin properties that are
// specific to this particular request, including
// agent-specific skin properties.
// 2. In the wrapped Skin instance. Any skin properties that are
// manually registered via a call to setProperty(Object, Object)
// will be stored in the wrapped skin.
// Note: no synchronization needed since we are in a
// a request-specific object.
Map properties = _getRequestSkinProperties();
assert(properties != null);
Object propertyValue = properties.get(key);
if (propertyValue == null)
{
propertyValue = _skin.getProperty(key);
}
return propertyValue;
}
@Override
public void setProperty(
Object key,
Object value)
{
Map properties = _getRequestSkinProperties();
if (properties != _NULL_PROPERTIES)
properties.put(key, value);
}
/**
* @deprecated Use addSkinAddition instead
* */
@Override
public void registerStyleSheet(
String styleSheetName
)
{
_skin.registerStyleSheet(styleSheetName);
}
@Override
public void addSkinAddition (
SkinAddition skinAddition
)
{
_skin.addSkinAddition(skinAddition);
}
@Override
public List getSkinAdditions ()
{
return _skin.getSkinAdditions();
}
/**
* Implementation of DocumentProviderSkin.getStyleSheetDocument().
*/
public StyleSheetDocument getStyleSheetDocument(StyleContext styleContext)
{
// If getStyleSheetDocument() is being called on us, this implies
// that the wrapped Skin must also be a DocumentProviderSkin.
assert(_skin instanceof DocumentProviderSkin);
return ((DocumentProviderSkin)_skin).getStyleSheetDocument(styleContext);
}
@Override
public boolean isDirty()
{
return _skin.isDirty();
}
@Override
public void setDirty(boolean dirty)
{
_skin.setDirty(dirty);
}
// Returns request-specific map of icon names to Icons
private Map _getRequestIcons()
{
if (_icons == null)
{
// We get to the request-specific icons via the
// StyleProvider. We need a CoreRenderingContext
// instance to get at the StyleProvider. This
// implementation assumes that the RenderingContext
// is going to be an instanceof CoreRenderingContext.
// This is a pretty good bet, since the only
// RenderingContext provided by Trinidad is
// CoreRenderingContext, and given the complexity of
// the CoreRenderingContext implementation, it seems
// unlikely that anyone would attempt to replace the
// implementation.
RenderingContext rc = RenderingContext.getCurrentInstance();
assert(rc instanceof CoreRenderingContext);
CoreRenderingContext crc = (CoreRenderingContext)rc;
StyleContext styleContext = crc.getStyleContext();
StyleProvider styleProvider = styleContext.getStyleProvider();
_icons = styleProvider.getIcons(styleContext);
// Under normal circumstances, the StyleProvider will return
// a non-null, modifiable map. If the skin/style subsystem
// has failed to initialize, however, the map may be null.
// Substitute an empty map so we don't need to check for null
// later.
if (_icons == null)
{
if (_LOG.isWarning())
_LOG.warning("_icons is an emptyMap because the skin/style " +
"subsystem has failed to initialize.");
_icons = _NULL_ICONS;
}
}
return _icons;
}
// Returns request-specific map of skin property key/values
private Map _getRequestSkinProperties()
{
if (_properties == null)
{
// We get to the request-specific properties via the
// StyleProvider. We need a CoreRenderingContext
// instance to get at the StyleProvider. This
// implementation assumes that the RenderingContext
// is going to be an instanceof CoreRenderingContext.
// This is a pretty good bet, since the only
// RenderingContext provided by Trinidad is
// CoreRenderingContext, and given the complexity of
// the CoreRenderingContext implementation, it seems
// unlikely that anyone would attempt to replace the
// implementation.
RenderingContext rc = RenderingContext.getCurrentInstance();
assert(rc instanceof CoreRenderingContext);
CoreRenderingContext crc = (CoreRenderingContext)rc;
StyleContext styleContext = crc.getStyleContext();
StyleProvider styleProvider = styleContext.getStyleProvider();
// skin properties are stored in an Map
_properties = styleProvider.getSkinProperties(styleContext);
// Under normal circumstances, the StyleProvider will return
// a non-null, modifiable map. If the skin/style subsystem
// has failed to initialize, however, the map may be null.
// Substitute an empty map so we don't need to check for null
// later.
if (_properties == null)
{
if (_LOG.isWarning())
_LOG.warning("_properties is an emptyMap because the skin/style " +
"subsystem has failed to initialize.");
_properties = _NULL_PROPERTIES;
}
}
return _properties;
}
// The wrapped skin
private final Skin _skin;
// The icon map specific to this request as served
// up by the StyleProvider.
private Map _icons;
// The skin properties map specific to this request as served
// up by the StyleProvider.
private Map _properties;
// Marker used to cache nulls.
private static final Icon _NULL_ICON = new NullIcon();
// Empty map used when StyleProvider.getIcons() fails;
private static final Map _NULL_ICONS = Collections.emptyMap();
// Empty map used when StyleProvider.getSkinProperties() fails;
private static final Map _NULL_PROPERTIES = Collections.emptyMap();
static final private TrinidadLogger _LOG = TrinidadLogger.createTrinidadLogger(RequestSkinWrapper.class);
}