// 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.callback;
import org.apache.hivemind.ApplicationRuntimeException;
import org.apache.tapestry.IExternalPage;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
/**
* A callback for returning to an {@link org.apache.tapestry.IExternalPage}.
* <p>
* Example usage of <tt>ExternalCallback</tt>:
* <p>
* The External page ensure a user is authenticated in the
* {@link org.apache.tapestry.IPage#validate(IRequestCycle)} method.
* If the user is not authenticated, they are redirected to the Login page, after
* setting a callback in the Login page.
* <p>
* The Login page <tt>formSubmit()</tt> {@link org.apache.tapestry.IActionListener}
* authenticates the user and then invokes {@link ICallback#performCallback(IRequestCycle)}
* to the External page.
* <pre>
* public class External extends BasePage implements IExternalPage {
*
* private Integer _itemId;
*
* public void validate(IRequestCycle cycle) throws RequestCycleException {
* Visit visit = (Visit) getVisit();
*
* if (!visit.isAuthenticated()) {
* Login login = (Login) cycle.getPage("Login");
*
* login.setCallback
* (new ExternalCallback(this, cycle.getServiceParameters()));
*
* throw new PageRedirectException(login);
* }
* }
*
* public void activateExternalPage(Object[] params, IRequestCycle cycle)
* throws RequestCycleException {
* _itemId = (Integer) params[0];
* }
* }
*
* public Login extends BasePage {
*
* private ICallback _callback;
*
* public void setCallback(ICallback _callback) {
* _callback = callback;
* }
*
* public void formSubmit(IRequestCycle cycle) {
* // Authentication code
* ..
*
* Visit visit = (Visit) getVisit();
*
* visit.setAuthenticated(true);
*
* if (_callback != null) {
* _callback.performCallback(cycle);
* }
* }
* }
* </pre>
*
* @see org.apache.tapestry.IExternalPage
* @see org.apache.tapestry.engine.ExternalService
*
* @author Malcolm Edgar
* @since 2.3
*
**/
public class ExternalCallback implements ICallback
{
private String _pageName;
private Object[] _parameters;
/**
* Creates a new ExternalCallback for the named <tt>IExternalPage</tt>.
* The parameters (which may be null) is retained, not copied.
*
**/
public ExternalCallback(String pageName, Object[] parameters)
{
_pageName = pageName;
_parameters = parameters;
}
/**
* Creates a new ExternalCallback for the page. The parameters
* (which may be null) is retained, not copied.
*
**/
public ExternalCallback(IExternalPage page, Object[] parameters)
{
_pageName = page.getPageName();
_parameters = parameters;
}
/**
* Invokes {@link IRequestCycle#setPage(String)} to select the previously
* identified <tt>IExternalPage</tt> as the response page and activates
* the page by invoking <tt>activateExternalPage()</tt> with the callback
* parameters and request cycle.
*
**/
public void performCallback(IRequestCycle cycle)
{
try
{
IExternalPage page = (IExternalPage) cycle.getPage(_pageName);
cycle.activate(page);
page.activateExternalPage(_parameters, cycle);
}
catch (ClassCastException ex)
{
throw new ApplicationRuntimeException(
Tapestry.format("ExternalCallback.page-not-compatible", _pageName),
ex);
}
}
public String toString()
{
StringBuffer buffer = new StringBuffer("ExternalCallback[");
buffer.append(_pageName);
buffer.append('/');
if (_parameters != null)
{
String sep = " ";
for (int i = 0; i < _parameters.length; i++)
{
buffer.append(sep);
buffer.append(_parameters[i]);
sep = ", ";
}
}
buffer.append(']');
return buffer.toString();
}
}