java/org/apache/jasper/runtime/ServletResponseWrapperInclude.java

/*
 * 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.
 */
package org.apache.jasper.runtime;

import java.io.IOException;
import java.io.PrintWriter;

import jakarta.servlet.ServletOutputStream;
import jakarta.servlet.ServletResponse;
import jakarta.servlet.http.HttpServletResponse;
import jakarta.servlet.http.HttpServletResponseWrapper;
import jakarta.servlet.jsp.JspWriter;

/**
 * ServletResponseWrapper used by the JSP 'include' action. This wrapper response object is passed to
 * RequestDispatcher.include(), so that the output of the included resource is appended to that of the including page.
 */
public class ServletResponseWrapperInclude extends HttpServletResponseWrapper {

    /**
     * PrintWriter which appends to the JspWriter of the including page.
     */
    private final PrintWriter printWriter;

    private final JspWriter jspWriter;

    /**
     * Creates a new response wrapper for include operations.
     * @param response the servlet response
     * @param jspWriter the JSP writer
     */
    public ServletResponseWrapperInclude(ServletResponse response, JspWriter jspWriter) {
        super((HttpServletResponse) response);
        this.printWriter = new PrintWriter(jspWriter);
        this.jspWriter = jspWriter;
    }

    /**
     * @return a wrapper around the JspWriter of the including page.
     */
    @Override
    public PrintWriter getWriter() throws IOException {
        return printWriter;
    }

    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        throw new IllegalStateException();
    }

    /**
     * Clears the output buffer of the JspWriter associated with the including page.
     */
    @Override
    public void resetBuffer() {
        try {
            jspWriter.clearBuffer();
        } catch (IOException ioe) {
            // Ignore
        }
    }
}