org.jaulp.wicket.behaviors.AjaxDownloadBehavior.java Source code

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Here is the source code for org.jaulp.wicket.behaviors.AjaxDownloadBehavior.java

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/**
 * Copyright (C) 2010 Asterios Raptis
 *
 * 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 org.jaulp.wicket.behaviors;

import org.apache.wicket.ajax.AjaxRequestTarget;
import org.apache.wicket.behavior.AbstractAjaxBehavior;
import org.apache.wicket.request.handler.resource.ResourceStreamRequestHandler;
import org.apache.wicket.request.resource.ContentDisposition;
import org.apache.wicket.util.resource.IResourceStream;

/**
 * This behavior enables us to initiate the download after the AJAX request has been completed.
 * 
 * Inspired from @see <a href=
 * "https://cwiki.apache.org/confluence/display/WICKET/AJAX+update+and+file+download+in+one+blow"
 * >https://cwiki.apache.org/confluence/display/WICKET/AJAX+update+and+file+
 * download+in+one+blow</a>.
 **/
public abstract class AjaxDownloadBehavior extends AbstractAjaxBehavior {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private boolean antiCache;

    public AjaxDownloadBehavior() {
        this(true);
    }

    public AjaxDownloadBehavior(boolean antiCache) {
        super();
        this.antiCache = antiCache;
    }

    /**
     * Call this method to initiate the download.
     * 
     * @param target
     *            the {@link AjaxRequestTarget}
     */
    public void initiate(AjaxRequestTarget target) {
        String url = getCallbackUrl().toString();

        if (antiCache) {
            url = url + (url.contains("?") ? "&" : "?");
            url = url + "antiCache=" + System.currentTimeMillis();
        }
        // the timeout is needed to let Wicket release the channel
        target.appendJavaScript("setTimeout(\"window.location.href='" + url + "'\", 100);");
    }

    @Override
    public void onRequest() {
        ResourceStreamRequestHandler handler = new ResourceStreamRequestHandler(getResourceStream(), getFileName());
        handler.setContentDisposition(ContentDisposition.ATTACHMENT);
        getComponent().getRequestCycle().scheduleRequestHandlerAfterCurrent(handler);
    }

    /**
     * Hook method for a file name which will let the browser prompt with a save/open dialog.
     * 
     * @return the file name
     */
    protected abstract String getFileName();

    /**
     * Hook method providing the actual resource stream.
     * 
     * @return the resource stream.
     */
    protected abstract IResourceStream getResourceStream();
}