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    
015    package 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     */
024    public 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    }