org.adho.dhconvalidator.ui.ExternalResourceRequestHandler.java Source code

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Here is the source code for org.adho.dhconvalidator.ui.ExternalResourceRequestHandler.java

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/*
 * Copyright (c) 2015 http://www.adho.org/
 * License: see LICENSE file
 */
package org.adho.dhconvalidator.ui;

import com.vaadin.server.RequestHandler;
import com.vaadin.server.VaadinRequest;
import com.vaadin.server.VaadinResponse;
import com.vaadin.server.VaadinSession;
import java.io.IOException;
import org.adho.dhconvalidator.Messages;
import org.adho.dhconvalidator.conversion.oxgarage.ZipResult;
import org.adho.dhconvalidator.properties.PropertyKey;

/**
 * This component serves external resources like images from the {@link ZipResult} of the conversion
 * for the visual feedback.
 *
 * @author marco.petris@web.de
 */
final class ExternalResourceRequestHandler implements RequestHandler {
    private static final int PATH_PREFIX_LENGTH = 7;
    private String imagePath;
    private ZipResult exampleZipResult;
    private String examplePictureName;

    public ExternalResourceRequestHandler(String imagePath) throws IOException {
        super();
        this.imagePath = imagePath;
        this.exampleZipResult = new ZipResult(Thread.currentThread().getContextClassLoader()
                .getResourceAsStream("/org/adho/dhconvalidator/conversion/example/1_Digital_Humanities.dhc"));
        this.examplePictureName = exampleZipResult
                .getExternalResourcePathsStartsWith(PropertyKey.tei_image_location.getValue().substring(1)) // skip leading slash
                .get(0) // there has to be exactly one image
                .substring(PropertyKey.tei_image_location.getValue().length()); // skip path information
    }

    @Override
    public boolean handleRequest(VaadinSession session, VaadinRequest request, VaadinResponse response)
            throws IOException {

        // does the request concern us?
        if (request.getPathInfo().startsWith("/popup" + imagePath)) {
            ZipResult zipResult = (ZipResult) VaadinSession.getCurrent()
                    .getAttribute(SessionStorageKey.ZIPRESULT.name());
            // if this is about the example picture we use the example ZipResult
            if (request.getPathInfo().endsWith(examplePictureName)) {
                zipResult = exampleZipResult;
            }

            if (zipResult != null) {
                byte[] resource = zipResult
                        .getExternalResource(request.getPathInfo().substring(PATH_PREFIX_LENGTH));
                if (resource != null) {
                    response.getOutputStream().write(resource);
                    return true;
                } else {
                    throw new IOException(Messages.getString("ExternalResourceRequestHandler.resourceNotFound",
                            request.getPathInfo().substring(PATH_PREFIX_LENGTH)));
                }
            }
        }
        return false;
    }
}