trunk/core/src/main/java/org/apache/struts2/util/VelocityStrutsUtil.java

/*
 * $Id$
 *
 * Copyright 2006 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.struts2.util;

import java.io.CharArrayWriter;
import java.io.IOException;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.views.velocity.VelocityManager;
import org.apache.velocity.context.Context;
import org.apache.velocity.exception.MethodInvocationException;
import org.apache.velocity.exception.ParseErrorException;
import org.apache.velocity.exception.ResourceNotFoundException;

import com.opensymphony.xwork2.util.OgnlValueStack;


/**
 * Struts velocity related util.
 *
 */
public class VelocityStrutsUtil extends StrutsUtil {

    private Context ctx;

    public VelocityStrutsUtil(Context ctx, OgnlValueStack stack, HttpServletRequest request, HttpServletResponse response) {
        super(stack, request, response);
        this.ctx = ctx;
    }

    public String evaluate(String expression) throws IOException, ResourceNotFoundException, MethodInvocationException, ParseErrorException {
        CharArrayWriter writer = new CharArrayWriter();
        VelocityManager.getInstance().getVelocityEngine().evaluate(ctx, writer, "Error parsing " + expression, expression);

        return writer.toString();
    }

}