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.script;
016    
017    import java.util.Map;
018    
019    import org.apache.hivemind.Resource;
020    import org.apache.tapestry.IRequestCycle;
021    import org.apache.tapestry.IScriptProcessor;
022    
023    /**
024     * Process object used when executing a
025     * {@link org.apache.tapestry.IScript script template}. This ScriptSession
026     * provides support
027     * 
028     * @author Howard M. Lewis Ship
029     * @since 4.0
030     */
031    public interface ScriptSession extends IScriptProcessor
032    {
033    
034        /**
035         * Evaluates an OGNL expression, where the root object for the expression is
036         * the {@link #getSymbols() symbols map}.
037         */
038        Object evaluate(String expression);
039    
040        /**
041         * Returns the resource for the script template.
042         */
043    
044        Resource getScriptTemplateResource();
045    
046        /**
047         * Returns the symbols (which may be created or updated during the execution
048         * of the script template).
049         */
050    
051        Map getSymbols();
052    
053        /**
054         * Returns the current request cycle.
055         */
056        IRequestCycle getRequestCycle();
057    
058        /**
059         * Evaluates an expression and coerces the result to a particlar type.
060         * 
061         * @since 4.0
062         * @see org.apache.tapestry.coerce.ValueConverter
063         */
064    
065        Object evaluate(String expression, Class desiredType);
066    }