001    // Copyright 2010 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.tapestry5;
016    
017    import org.apache.tapestry5.annotations.RequestParameter;
018    import org.apache.tapestry5.corelib.components.Zone;
019    
020    /**
021     * Defines constants for common query parameters passed in requests from the client.
022     * 
023     * @see RequestParameter
024     */
025    public class QueryParameterConstants
026    {
027        /**
028         * The client-side id of the element being updated in an Ajax request. This is very useful when writing
029         * new content that may update the same zone dynamically, even when the {@link Zone} has allocated a dynamic
030         * client-side id during initial render.
031         */
032        public static final String ZONE_ID = "t:zoneid";
033    }