TextPreviewController.java

/**
 * <a href="http://www.openolat.org">
 * OpenOLAT - Online Learning and Training</a><br>
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); <br>
 * you may not use this file except in compliance with the License.<br>
 * You may obtain a copy of the License at the
 * <a href="http://www.apache.org/licenses/LICENSE-2.0">Apache homepage</a>
 * <p>
 * Unless required by applicable law or agreed to in writing,<br>
 * software distributed under the License is distributed on an "AS IS" BASIS, <br>
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. <br>
 * See the License for the specific language governing permissions and <br>
 * limitations under the License.
 * <p>
 * Initial code contributed and copyrighted by<br>
 * frentix GmbH, http://www.frentix.com
 * <p>
 */
package org.olat.modules.qpool.ui;

import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StringWriter;

import org.apache.commons.io.IOUtils;
import org.olat.core.CoreSpringFactory;
import org.olat.core.gui.UserRequest;
import org.olat.core.gui.components.Component;
import org.olat.core.gui.components.velocity.VelocityContainer;
import org.olat.core.gui.control.Event;
import org.olat.core.gui.control.WindowControl;
import org.olat.core.gui.control.controller.BasicController;
import org.olat.core.util.vfs.VFSLeaf;
import org.olat.modules.qpool.QuestionItem;
import org.olat.modules.qpool.QPoolService;

/**
 * 
 * Initial date: 27.02.2013<br>
 * @author srosse, stephane.rosse@frentix.com, http://www.frentix.com
 *
 */
public class TextPreviewController extends BasicController {

	private final VelocityContainer mainVC;
	private final QPoolService qpoolService;
	
	public TextPreviewController(UserRequest ureq, WindowControl wControl, QuestionItem qitem, boolean summary) {
		super(ureq, wControl);
		qpoolService = CoreSpringFactory.getImpl(QPoolService.class);
		mainVC = createVelocityContainer("text_preview");
		
		VFSLeaf leaf = qpoolService.getRootLeaf(qitem);
		if(leaf == null) {
			//no data to preview
		} else {
			String txt = readSummary(leaf);
			if(summary && txt.length() > 2000) {
				txt = txt.substring(0, 2000);
			}
			mainVC.contextPut("text", txt);
		}
		putInitialPanel(mainVC);
	}

	@Override
	protected void doDispose() {
		//
	}
	
	protected String readSummary(VFSLeaf leaf) {
    StringWriter out = new StringWriter();
    InputStream in = leaf.getInputStream();
    InputStreamReader inr = new InputStreamReader(in);
		try {
			char[] buffer = new char[4096];
			
			int count = 0;
	    int n = 0;
	    while (-1 != (n = inr.read(buffer))) {
	        out.write(buffer, 0, n);
	        count += n;
	        if(count >= 10000) {
	        	break;
	        }
	    }
		} catch (Exception e) {
			logError("", e);
		} finally {
			IOUtils.closeQuietly(inr);
			IOUtils.closeQuietly(in);
		}
  	return out.toString();
	}

	@Override
	protected void event(UserRequest ureq, Component source, Event event) {
		//
	}
}