com.opencredo.servlet.BookDisplayCoverController.java Source code

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Here is the source code for com.opencredo.servlet.BookDisplayCoverController.java

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/*
 * Copyright 2005-2008 the original author or authors.
 *
 * 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 com.opencredo.servlet;

import java.io.IOException;

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

import org.springframework.beans.factory.annotation.Required;
import org.springframework.web.bind.ServletRequestUtils;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.AbstractController;

import com.opencredo.domain.Book;
import com.opencredo.service.BookService;

public class BookDisplayCoverController extends AbstractController {

    private BookService bookService;

    private static final String CONTENT_TYPE = "image/png";

    protected ModelAndView handleRequestInternal(HttpServletRequest request, HttpServletResponse response)
            throws IllegalStateException, IOException {

        // set the content type
        response.setContentType(CONTENT_TYPE);

        // get the ID of the book -- set "bad request" if its not a valid integer
        Integer id;
        try {
            id = ServletRequestUtils.getIntParameter(request, "book");
            if (id == null)
                throw new IllegalStateException("must specify the book id");
        } catch (Exception e) {
            response.sendError(HttpServletResponse.SC_BAD_REQUEST, "invalid book");
            return null;
        }

        // get the book from the service
        Book book = bookService.getBook(id);

        // if the book doesn't exist then set "not found"
        if (book == null) {
            response.sendError(HttpServletResponse.SC_NOT_FOUND, "no such book");
            return null;
        }

        // if the book doesn't have a picture, set "not found"
        if (book.getCoverPng() == null) {
            response.sendError(HttpServletResponse.SC_NOT_FOUND, "book has no image");
            return null;
        }

        if (logger.isDebugEnabled())
            logger.debug("returning cover for book " + book.getKey() + " '" + book.getTitle() + "'" + " size: "
                    + book.getCoverPng().length + " bytes");

        // send the image
        response.setContentLength(book.getCoverPng().length);
        response.getOutputStream().write(book.getCoverPng());
        response.getOutputStream().flush();

        // we already handled the response
        return null;
    }

    @Required
    public void setBookService(BookService bookService) {
        this.bookService = bookService;
    }
}