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 org.apache.tapestry.engine.ServiceEncoding;
018    
019    /**
020     * Service tapestry.persist.ClientPropertyPersistenceScope. Determines whether a particular property
021     * needs to be persisted or not.
022     * 
023     * @author Mindbridge
024     * @since 4.0
025     * @see org.apache.tapestry.record.ClientPropertyPersistenceStrategy
026     */
027    public interface ClientPropertyPersistenceScope
028    {
029        /**
030         * Determines whether state should be encoded for the request.
031         * 
032         * @param encoding
033         *            identifies the service, URL and base set of parameters
034         * @param pageName
035         *            the page for which data is potentially to be encoded
036         * @param data
037         * @return true if state should be encoded into the encoding, false otherwise
038         */
039    
040        public boolean shouldEncodeState(ServiceEncoding encoding, String pageName,
041                PersistentPropertyData data);
042    
043        /**
044         * Constructs a parameter name for a particular page name. The parameter name can be recognized
045         * (in a later request) by the {@link #isParameterForScope(String)} method.
046         * 
047         * @param pageName
048         *            the name of the page for which a corresponding parameter name should be generated.
049         * @returns a query parameter name that identifies the page and this client persistence scope.
050         */
051    
052        public String constructParameterName(String pageName);
053    
054        /**
055         * Checks a parameter to see if it was the result of {@link #constructParameterName(String)} for
056         * this persistence scope.
057         * 
058         * @param parameterName
059         *            a query parameter name
060         * @return true if the parameterName was genereted (i.e., is properly prefixed) by this scope,
061         *         false otherwise.
062         */
063    
064        public boolean isParameterForScope(String parameterName);
065    
066        /**
067         * Extracts a page name from a query parameter name.
068         * 
069         * @param parameterName
070         *            the paramter name, for which {@link #isParameterForScope(String) must return true
071         * @return the name of the page
072         */
073        public String extractPageName(String parameterName);
074    }