001/*
002 *  Copyright 2010 Anyware Services
003 *
004 *  Licensed under the Apache License, Version 2.0 (the "License");
005 *  you may not use this file except in compliance with the License.
006 *  You may obtain a copy of the License at
007 *
008 *      http://www.apache.org/licenses/LICENSE-2.0
009 *
010 *  Unless required by applicable law or agreed to in writing, software
011 *  distributed under the License is distributed on an "AS IS" BASIS,
012 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 *  See the License for the specific language governing permissions and
014 *  limitations under the License.
015 */
016package org.ametys.web.inputdata;
017
018import org.apache.cocoon.ProcessingException;
019import org.xml.sax.ContentHandler;
020import org.xml.sax.SAXException;
021
022import org.ametys.web.cache.pageelement.PageElementCache;
023import org.ametys.web.repository.page.Page;
024import org.ametys.web.repository.site.Site;
025
026/**
027 * Abstraction for providing data at view-time by SAXing events.
028 */
029public interface InputData
030{
031    /**
032     * Returns true if this {@link InputData} is cacheable for the current site and if possible page.
033     * @param site the current {@link Site}.
034     * @param page the current {@link Page}. Can be null.
035     * @return true if this {@link InputData} is cacheable for the current site or page.
036     */
037    public boolean isCacheable(Site site, Page page);
038    
039    /**
040     * Returns true if the resulting SAX events should be actually stored in the central {@link PageElementCache}.<br>
041     * It may be useful to return false for some InputData managing their own cache and don't wanting to waste space in the central cache.<br>
042     * This method is only called if {@link #isCacheable(Site, Page)} returns true.
043     * @param site the current {@link Site}.
044     * @param page the current {@link Page}. Can be null.
045     * @return true if the content is cacheable and should be stored in the {@link PageElementCache}.
046     */
047    public default boolean shouldBeCached(Site site, Page page)
048    {
049        return true;
050    }
051    
052    /**
053     * Generates SAX events for providing data.
054     * @param handler the content handler to SAX into.
055     * @throws SAXException if an error occurs while SAXing.
056     * @throws ProcessingException if an error occurs during processing.
057     */
058    public void toSAX(ContentHandler handler) throws SAXException, ProcessingException;
059}