// 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 org.apache.hivemind.ApplicationRuntimeException;
import org.apache.tapestry.IMarkupWriter;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.components.ILinkComponent;
import org.apache.tapestry.engine.ILink;
/**
* An {@link ILinkRenderer} implementation that generates an HTML button.
* This is particularly useful for implementing cancel buttons.
*
* @author Paul Ferraro
* @since 4.0
*/
public class ButtonLinkRenderer implements ILinkRenderer
{
public static final ILinkRenderer SHARED_INSTANCE = new ButtonLinkRenderer();
/**
* @see org.apache.tapestry.link.ILinkRenderer#renderLink(org.apache.tapestry.IMarkupWriter,
* org.apache.tapestry.IRequestCycle, org.apache.tapestry.components.ILinkComponent)
*/
public void renderLink(IMarkupWriter writer, IRequestCycle cycle, ILinkComponent component)
{
if (cycle.getAttribute(Tapestry.LINK_COMPONENT_ATTRIBUTE_NAME) != null)
{
String message = Tapestry.getMessage("AbstractLinkComponent.no-nesting");
throw new ApplicationRuntimeException(message, component, null, null);
}
cycle.setAttribute(Tapestry.LINK_COMPONENT_ATTRIBUTE_NAME, component);
ILink link = component.getLink(cycle);
writer.begin("button");
writer.attribute("type", "button");
if (component.isDisabled())
{
writer.attribute("disabled", "disabled");
}
String url = link.getURL(component.getAnchor(), true);
String target = component.getTarget();
String onclick = (target == null) ? getScript(url) : getScript(url, target);
writer.attribute("onclick", onclick);
component.renderAdditionalAttributes(writer, cycle);
IMarkupWriter wrappedWriter = writer.getNestedWriter();
component.renderBody(wrappedWriter, cycle);
wrappedWriter.close();
writer.end();
cycle.removeAttribute(Tapestry.LINK_COMPONENT_ATTRIBUTE_NAME);
}
/**
* Generates the onclick event handler that opens the specified url in the current window.
* @param url the url generated by this link
* @return a JavaScript onclick event handler
*/
protected String getScript(String url)
{
return "window.location='" + url + "'";
}
/**
* Generates the onclick event handler that opens the specified url in the specified window or frame.
* @param url the url generated by this link
* @param target the name of the target window or frame
* @return a JavaScript onclick event handler
*/
protected String getScript(String url, String target)
{
return "window.open('" + url + "','" + target + "')";
}
}