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     * Defines constants for query parameters names commonly used by services.
019     * 
020     * @author Howard M. Lewis Ship
021     * @since 4.0
022     */
023    public class ServiceConstants
024    {
025        /**
026         * The name of the service responsible for processing the request.
027         */
028        public static final String SERVICE = "service";
029    
030        /**
031         * The name of the page to activate when processing the service.
032         */
033    
034        public static final String PAGE = "page";
035    
036        /**
037         * The id path to the component within the page. By convention, this component is within the
038         * {@link #PAGE}.
039         */
040    
041        public static final String COMPONENT = "component";
042    
043        /**
044         * The name of the page containing the component; this is only specified when the component is
045         * contained by a page other than the activate page ({@link #PAGE}).
046         */
047    
048        public static final String CONTAINER = "container";
049    
050        /**
051         * A flag indicating whether a session was active when the link was rendered. If this is true,
052         * but no session is active when the request is processed, the a service may at its discression
053         * throw a {@link org.apache.tapestry.StaleLinkException}
054         */
055    
056        public static final String SESSION = "session";
057    
058        /**
059         * Contains a number of additional strings meaningful to the application (the term service
060         * parameters is something of an entrenched misnomer, a better term would have been application
061         * parameters). These parameters are typically objects that have been squeezed into strings by
062         * {@link org.apache.tapestry.services.DataSqueezer}.
063         * <p>
064         * The value is currently "sp" for vaguely historical reasons ("service parameter"), though it
065         * would be better if it were "lp" (for "listener parameter"), or just "param" perhaps.
066         */
067    
068        public static final String PARAMETER = "sp";
069    
070        /**
071         * Contains a string list of the parts in a response that should be updated. Parts
072         * can be both components and normal html tags resolved via their unique id's.
073         */
074        public static final String UPDATE_PARTS = "updateParts";
075        
076        /**
077         * A list of all the constants defined by this class.
078         * 
079         * @see org.apache.tapestry.form.FormSupportImpl
080         */
081        public static final String[] RESERVED_IDS = { SERVICE, PAGE, COMPONENT, CONTAINER, SESSION, PARAMETER };
082    }