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
015package org.apache.tapestry.record;
016
017import java.util.List;
018
019/**
020 * Responsible for encoding {@link org.apache.tapestry.record.PropertyChange}s into and out of plain
021 * strings.
022 * 
023 * @author Howard M. Lewis Ship
024 * @since 4.0
025 */
026public interface PersistentPropertyDataEncoder
027{
028    /**
029     * Encodes a (possibly empty) list of {@link PropertyChange}s into a string representation that
030     * can later be decoded.
031     * 
032     * @returns encoded string (possibly empty, but not null)
033     */
034    public String encodePageChanges(List changes);
035
036    /**
037     * Takes a string with an encoded set of page changes, and converts it back into a list of
038     * {@link org.apache.tapestry.record.PropertyChange}s.
039     */
040
041    public List decodePageChanges(String encoded);
042
043}