/*
 *  ====================================================================
 *  The Apache Software License, Version 1.1
 *
 *  Copyright (c) 2002 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://www.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" and
 *  "Apache 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",
 *  "Apache Tapestry", nor may "Apache" appear in their name, without
 *  prior written permission of the Apache Software Foundation.
 *
 *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 *  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 *  ITS CONTRIBUTORS 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 net.sf.tapestry;

/**
 *  Abstracts the process of loading pages from thier specifications as
 *  well as pooling of pages once loaded.  
 *
 *  <p>If the required page is not available, a page source may use an
 *  instance of {@link IPageLoader} to actually load the
 *  page (and all of its nested components).
 *
 *  @author Howard Lewis Ship
 *  @version $Id$
 * 
 **/

public interface IPageSource
{
    /**
     *  Gets a given page for the engine.  This may involve using a previously
     *  loaded page from a pool of available pages, or the page may be loaded as needed.
     * 
     *  <p>Incompatible change in 2.2:  First parameter changed from
     *  {@link IEngine} to {@link IRequestCycle}.
     *
     **/

    public IPage getPage(IRequestCycle cycle, String pageName, IMonitor monitor) throws PageLoaderException;

    /**
     *  Invoked after the engine is done with the page
     *  (typically, after the response to the client has been sent).
     *  The page is returned to the pool for later reuse.
     *
     **/

    public void releasePage(IPage page);

    /**
     *  Invoked to have the source clear any internal cache.  This is most often
     *  used when debugging an application.
     *
     **/

    public void reset();

    /**
     *  Gets a field binding for the named field (the name includes the class name
     *  and the field).  If no such binding exists, then one is created, otherwise
     *  the existing binding is returned. 
     *
     * @since 1.0.2
     **/

    public IBinding getFieldBinding(String fieldName);

    /**
     *  Like {@link #getFieldBinding(String)}, except for static bindings.
     *
     * @since 1.0.2
     **/

    public IBinding getStaticBinding(String value);

    /**
     *  Gets a cached asset.
     *
     *  @since 1.0.2
     *
     **/

    public IAsset getExternalAsset(String URL);

    /**
     *  Gets a cached asset.
     *
     *  @since 1.0.2
     *
     **/

    public IAsset getContextAsset(String assetPath);

    /**
     *  Gets a cached asset.
     *
     *  @since 1.0.2
     *
     **/

    public IAsset getPrivateAsset(String resourcePath);
}