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
015package org.apache.tapestry.script;
016
017import java.util.Map;
018
019import org.apache.hivemind.Resource;
020import org.apache.tapestry.IRequestCycle;
021import org.apache.tapestry.IScriptProcessor;
022
023/**
024 * Process object used when executing a {@link org.apache.tapestry.IScript script template}. This
025 * ScriptSession provides support
026 * 
027 * @author Howard M. Lewis Ship
028 * @since 4.0
029 */
030public interface ScriptSession extends IScriptProcessor
031{
032    /**
033     * Evaluates an OGNL expression, where the root object for the expression is the
034     * {@link #getSymbols() symbols map}.
035     */
036    public Object evaluate(String expression);
037
038    /**
039     * Returns the resource for the script template.
040     */
041
042    public Resource getScriptTemplateResource();
043
044    /**
045     * Returns the symbols (which may be created or updated during the execution of the script
046     * template).
047     */
048
049    public Map getSymbols();
050
051    /**
052     * Returns the current request cycle.
053     */
054    public IRequestCycle getRequestCycle();
055
056    /**
057     * Evaluates an expression and coerces the result to a particlar type.
058     * 
059     * @since 4.0
060     * @see org.apache.tapestry.coerce.ValueConverter
061     */
062
063    public Object evaluate(String expression, Class desiredType);
064}