001    // Copyright 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.tapestry.record;
016    
017    import java.util.Collection;
018    
019    import org.apache.tapestry.engine.ServiceEncoding;
020    
021    /**
022     * Defines how a persistent property is made persistent. The typical implementation is to store the
023     * persistent property into the session as a session attribute.
024     * 
025     * @author Howard M. Lewis Ship
026     * @since 4.0
027     */
028    public interface PropertyPersistenceStrategy
029    {
030        /**
031         * Stores the new value.
032         * 
033         * @param pageName
034         *            the name of the page containing the property
035         * @param idPath
036         *            the path to the component with the property (may be null)
037         * @param propertyName
038         *            the name of the property to be persisted
039         * @param newValue
040         *            the new value (which may be null)
041         */
042    
043        public void store(String pageName, String idPath, String propertyName, Object newValue);
044    
045        /**
046         * Returns a collection of {@link org.apache.tapestry.record.PropertyChange}s. These represent
047         * prior changes previously stored. The order is not significant. Must not return null. Does not
048         * have to reflect changes made during the current request (this method is typically invoked as
049         * part of rolling back a page to a prior state, before any further changes are possible).
050         */
051    
052        public Collection getStoredChanges(String pageName);
053    
054        /**
055         * Invoked to discard any stored changes for the specified page.
056         */
057        public void discardStoredChanges(String pageName);
058    
059        /**
060         * Invoked by a {@link org.apache.tapestry.services.LinkFactory} , the parameters may be
061         * modified (added to) to store information related to persistent properties. This method is
062         * forwarded to all {@link PropertyPersistenceStrategy}s.
063         * 
064         * @param encoding
065         *            Service encoding, which indentifies the URL and the query parameters from which
066         *            the {@link org.apache.tapestry.engine.ILink} will be created.
067         * @param post
068         *            if true, then the link will be used for a post (not a get, i.e., for a HTML form);
069         *            this may affect what information is encoded into the link
070         * @see PropertyPersistenceStrategySource
071         */
072    
073        public void addParametersForPersistentProperties(ServiceEncoding encoding, boolean post);
074    }