Package org.apache.tapestry.callback

Source Code of org.apache.tapestry.callback.ExternalCallback

/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2003 The Apache Software Foundation.  All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution.
*
* 3. The end-user documentation included with the redistribution,
*    if any, must include the following acknowledgment:
*       "This product includes software developed by the
*        Apache Software Foundation (http://apache.org/)."
*    Alternately, this acknowledgment may appear in the software itself,
*    if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation", "Tapestry"
*    must not be used to endorse or promote products derived from this
*    software without prior written permission. For written
*    permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
*    or "Tapestry", nor may "Apache" or "Tapestry" appear in their
*    name, without prior written permission of the Apache Software Foundation.
*
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation.  For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/

package org.apache.tapestry.callback;

import org.apache.tapestry.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
*
@version $Id: ExternalCallback.java,v 1.5 2003/05/28 13:41:44 hlship Exp $
@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();
    }   
}
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