001// Copyright 2004, 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.services;
016
017/**
018 * Lightweight serialization used to encode values into strings that are stored in query parameters
019 * and hidden fields.
020 * 
021 * @author Howard Lewis Ship
022 * @since 4.0
023 */
024public interface DataSqueezer
025{
026    /**
027     * Squeezes the data object into a String by locating an appropriate adaptor that can perform
028     * the conversion. data may be null.
029     */
030    public String squeeze(Object data);
031
032    /**
033     * A convenience; invokes {@link #squeeze(Object)}for each element in the data array. If data
034     * is null, returns null.
035     */
036    public String[] squeeze(Object[] data);
037
038    /**
039     * Unsqueezes the string. Note that in a special case, where the first character of the string
040     * is not a recognized prefix, it is assumed that the string is simply a string, and returned
041     * with no change.
042     */
043    public Object unsqueeze(String string);
044
045    /**
046     * Convenience method for unsqueezing many strings (back into objects).
047     * <p>
048     * If strings is null, returns null.
049     */
050    public Object[] unsqueeze(String[] strings);
051}