// Copyright 2004, 2005 The Apache Software Foundation
//
// Licensed 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.tapestry.link;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.apache.tapestry.AbstractComponent;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.PageRenderSupport;
import org.apache.tapestry.TapestryUtils;
import org.apache.tapestry.components.ILinkComponent;
import org.apache.tapestry.components.LinkEventType;
import org.apache.tapestry.engine.IEngineService;
import org.apache.tapestry.engine.ILink;
/**
* Base class for implementations of {@link ILinkComponent}. Includes a disabled attribute (that
* should be bound to a disabled parameter), an anchor attribute, and a renderer attribute (that
* should be bound to a renderer parameter). A default, shared instance of
* {@link org.apache.tapestry.link.DefaultLinkRenderer}is used when no specific renderer is
* provided.
*
* @author Howard Lewis Ship
*/
public abstract class AbstractLinkComponent extends AbstractComponent implements ILinkComponent
{
private Map _eventHandlers;
public abstract boolean isDisabled();
/**
* Adds an event handler (typically, from a wrapped component such as a
* {@link org.apache.tapestry.html.Rollover}).
*/
public void addEventHandler(LinkEventType eventType, String functionName)
{
Object currentValue;
if (_eventHandlers == null)
_eventHandlers = new HashMap();
currentValue = _eventHandlers.get(eventType);
// The first value is added as a String
if (currentValue == null)
{
_eventHandlers.put(eventType, functionName);
return;
}
// When adding the second value, convert to a List
if (currentValue instanceof String)
{
List list = new ArrayList();
list.add(currentValue);
list.add(functionName);
_eventHandlers.put(eventType, list);
return;
}
// For the third and up, add the new function to the List
List list = (List) currentValue;
list.add(functionName);
}
/**
* Renders the link by delegating to an instance of {@link ILinkRenderer}.
*/
protected void renderComponent(IMarkupWriter writer, IRequestCycle cycle)
{
getRenderer().renderLink(writer, cycle, this);
}
protected void cleanupAfterRender(IRequestCycle cycle)
{
_eventHandlers = null;
super.cleanupAfterRender(cycle);
}
protected void writeEventHandlers(IMarkupWriter writer, IRequestCycle cycle)
{
String name = null;
if (_eventHandlers == null)
return;
PageRenderSupport pageRenderSupport = TapestryUtils.getPageRenderSupport(cycle, this);
Iterator i = _eventHandlers.entrySet().iterator();
while (i.hasNext())
{
Map.Entry entry = (Map.Entry) i.next();
LinkEventType type = (LinkEventType) entry.getKey();
name = writeEventHandler(
writer,
pageRenderSupport,
name,
type.getAttributeName(),
entry.getValue());
}
}
protected String writeEventHandler(IMarkupWriter writer, PageRenderSupport pageRenderSupport,
String name, String attributeName, Object value)
{
String wrapperFunctionName;
if (value instanceof String)
{
wrapperFunctionName = (String) value;
}
else
{
String finalName = name == null ? pageRenderSupport.getUniqueString("Link") : name;
wrapperFunctionName = attributeName + "_" + finalName;
StringBuffer buffer = new StringBuffer();
buffer.append("function ");
buffer.append(wrapperFunctionName);
buffer.append(" ()\n{\n");
Iterator i = ((List) value).iterator();
while (i.hasNext())
{
String functionName = (String) i.next();
buffer.append(" ");
buffer.append(functionName);
buffer.append("();\n");
}
buffer.append("}\n\n");
pageRenderSupport.addBodyScript(buffer.toString());
}
writer.attribute(attributeName, "javascript:" + wrapperFunctionName + "();");
return name;
}
/** @since 3.0 * */
public abstract ILinkRenderer getRenderer();
public abstract void setRenderer(ILinkRenderer renderer);
public void renderAdditionalAttributes(IMarkupWriter writer, IRequestCycle cycle)
{
writeEventHandlers(writer, cycle);
// Generate additional attributes from informal parameters.
renderInformalParameters(writer, cycle);
}
/**
* Utility method for subclasses; Gets the named service from the engine and invokes
* {@link IEngineService#getLink(IRequestCycle, org.apache.tapestry.IComponent, Object[])}on
* it.
*
* @since 3.0
* @deprecated To be removed in 4.1; links may now have the necessary engine service injected.
*/
protected ILink getLink(IRequestCycle cycle, String serviceName, Object parameter)
{
IEngineService service = cycle.getEngine().getService(serviceName);
return service.getLink(cycle, parameter);
}
public abstract String getAnchor();
public ILink getLink(IRequestCycle cycle)
{
return null;
}
/**
* Sets the renderer parameter property to its default value
* {@link DefaultLinkRenderer#SHARED_INSTANCE}.
*
* @since 3.0
*/
protected void finishLoad()
{
setRenderer(DefaultLinkRenderer.SHARED_INSTANCE);
}
}