src/main/java/org/apache/commons/ognl/enhance/ExpressionAccessor.java

package org.apache.commons.ognl.enhance;

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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.
 */

import org.apache.commons.ognl.Node;
import org.apache.commons.ognl.OgnlContext;

/**
 * Provides pure java expression paths to get/set values from an ognl expression. This is achieved by taking an existing
 * {@link Node} parsed expression and using bytecode enhancements to do the same work using pure java vs the ognl
 * interpreter.
 */
public interface ExpressionAccessor
{

    /**
     * Gets the value represented by this expression path, if any.
     *
     * @param context The standard ognl context used for variable substitution/etc.
     * @param target The root object this expression is meant for.
     * @return The evaluated value, if any.
     */
    Object get( OgnlContext context, Object target );

    /**
     * Sets the value represented by this expression path, if possible.
     *
     * @param context The standard ognl context used for variable substitution/etc.
     * @param target The root object this expression is meant for.
     * @param value The new value to set if this expression references a settable property.
     */
    void set( OgnlContext context, Object target, Object value );

    /**
     * Used to set the original root expression node on instances where the compiled version has to fall back to
     * interpreted syntax because of compilation failures.
     *
     * @param expression The root expression node used to generate this accessor.
     */
    void setExpression( Node expression );
}