nl.mineleni.cbsviewer.servlet.GZIPHttpServletResponseWrapper.java Source code

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Here is the source code for nl.mineleni.cbsviewer.servlet.GZIPHttpServletResponseWrapper.java

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/*
 * Copyright (c) 2014, Dienst Landelijk Gebied - Ministerie van Economische Zaken
 * 
 * Gepubliceerd onder de BSD 2-clause licentie, 
 * zie https://github.com/MinELenI/CBSviewer/blob/master/LICENSE.md voor de volledige licentie.
 */
package nl.mineleni.cbsviewer.servlet;

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

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpServletResponseWrapper;

import org.apache.http.HttpHeaders;

/**
 * The Class GZIPHttpServletResponseWrapper.
 */
public class GZIPHttpServletResponseWrapper extends HttpServletResponseWrapper {
    /** gecomprimeerde output. */
    private ServletResponseGZIPOutputStream gzipStream;
    /** te comprimeren output. */
    private ServletOutputStream outputStream;
    /** output. */
    private PrintWriter printWriter;

    /**
     * Instantiates a new GZIP http servlet response wrapper.
     *
     * @param response
     *            the response
     * @throws IOException
     *             Signals that an I/O exception has occurred.
     */
    public GZIPHttpServletResponseWrapper(HttpServletResponse response) throws IOException {
        super(response);
        response.addHeader(HttpHeaders.CONTENT_ENCODING, "gzip");
    }

    /**
     * Finish.
     *
     * @throws IOException
     *             Signals that an I/O exception has occurred.
     */
    public void finish() throws IOException {
        if (printWriter != null) {
            printWriter.close();
        }
        if (outputStream != null) {
            outputStream.close();
        }
        if (gzipStream != null) {
            gzipStream.close();
        }
    }

    /*
     * (non-Javadoc)
     * 
     * @see javax.servlet.ServletResponseWrapper#flushBuffer()
     */
    @Override
    public void flushBuffer() throws IOException {
        if (printWriter != null) {
            printWriter.flush();
        }
        if (outputStream != null) {
            outputStream.flush();
        }
        super.flushBuffer();
    }

    /*
     * (non-Javadoc)
     * 
     * @see javax.servlet.ServletResponseWrapper#getOutputStream()
     */
    @Override
    public ServletOutputStream getOutputStream() throws IOException {
        if (printWriter != null) {
            throw new IllegalStateException("printWriter already defined");
        }
        if (outputStream == null) {
            initGzip();
            outputStream = gzipStream;
        }
        return outputStream;
    }

    /*
     * (non-Javadoc)
     * 
     * @see javax.servlet.ServletResponseWrapper#getWriter()
     */
    @Override
    public PrintWriter getWriter() throws IOException {
        if (outputStream != null) {
            throw new IllegalStateException("printWriter already defined");
        }
        if (printWriter == null) {
            initGzip();
            printWriter = new PrintWriter(new OutputStreamWriter(gzipStream, getResponse().getCharacterEncoding()));
        }
        return printWriter;
    }

    /*
     * (non-Javadoc)
     * 
     * @see javax.servlet.ServletResponseWrapper#setContentLength(int)
     */
    @Override
    public void setContentLength(int len) {
    }

    /**
     * Inits the gzip.
     *
     * @throws IOException
     *             Signals that an I/O exception has occurred.
     */
    private void initGzip() throws IOException {
        gzipStream = new ServletResponseGZIPOutputStream(getResponse().getOutputStream());
    }

}