it.unimi.di.big.mg4j.query.InputStreamItem.java Source code

Introduction

Here is the source code for it.unimi.di.big.mg4j.query.InputStreamItem.java

Source

package it.unimi.di.big.mg4j.query;

/*       
 * MG4J: Managing Gigabytes for Java (big)
 *
 * Copyright (C) 2005-2015 Sebastiano Vigna 
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 */

import it.unimi.di.big.mg4j.document.DocumentCollection;

import java.io.IOException;
import java.io.InputStream;

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

import org.apache.commons.io.IOUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/** An item serving a raw input stream from the document collection.
 * 
 * <P>This kind of {@link it.unimi.di.big.mg4j.query.QueryServlet} item will load into the browser
 * the stream returned by the document collection for the given document. Using the system property
 * <samp>it.unimi.di.big.mg4j.query.InputStreamItem.skip</samp>, you can set a number of sub-input streams
 * that will be skipped by calling {@link java.io.InputStream#reset()} (see {@link it.unimi.di.big.mg4j.document}).
 */

public class InputStreamItem extends HttpServlet {
    private static final long serialVersionUID = 1L;
    private static final Logger LOGGER = LoggerFactory.getLogger(InputStreamItem.class);
    private static final int skip = Integer.getInteger(InputStreamItem.class.getName() + ".skip", 0).intValue();

    protected void doGet(final HttpServletRequest request, final HttpServletResponse response) throws IOException {
        try {
            if (request.getParameter("m") != null && request.getParameter("doc") != null) {
                DocumentCollection collection = (DocumentCollection) getServletContext().getAttribute("collection");
                if (collection == null)
                    LOGGER.error("The servlet context does not contain a document collection.");
                response.setContentType(request.getParameter("m"));
                response.setCharacterEncoding("UTF-8");
                InputStream rawContent = collection.stream(Long.parseLong(request.getParameter("doc")));
                for (int i = skip; i-- != 0;)
                    rawContent.reset();
                IOUtils.copy(rawContent, response.getOutputStream());
            }
        } catch (RuntimeException e) {
            e.printStackTrace();
            LOGGER.error(e.toString());
            throw e;
        }
    }

    protected void doPost(final HttpServletRequest request, final HttpServletResponse response) throws IOException {
        doGet(request, response);
    }
}