tapestry-framework/src/org/apache/tapestry/engine/ExpressionCache.java

//  Copyright 2008 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package org.apache.tapestry.engine;

import ognl.Node;

/**
 * Cache of compiled OGNL expressions.
 *
 * @author Howard M. Lewis Ship
 * @since 4.0
 */
public interface ExpressionCache
{
    /**
     * Returns the compiled ognl expression for the given target object class / expression
     * combination.
     *
     * @param target
     *          The object this expression is to be used for.
     * @param expression
     *          The expression.
     * @return
     *      The compiled (or new if neccessary) ognl statement.
     */
    Object get(Object target, String expression);

    /**
     * Stores a parsed ognl expression for the given object type.
     *
     * @param target
     *          The target object expression compiled for.
     * @param expression
     *          The ognl string expression node represents.
     * @param node
     *          The parsed OGNL expression to cache.
     */
    void cache(Object target, String expression, Node node);

    /**
     * Invoked by {@link AbstractEngine} to clear all cache data.
     */
    void reset();
}