/*
 * Copyright 2014 Federal Chancellery Austria MOA-ID has been developed in a cooperation between
 * BRZ, the Federal Chancellery Austria - ICT staff unit, and Graz University of Technology.
 *
 * Licensed under the EUPL, Version 1.1 or - as soon they will be approved by the European
 * Commission - subsequent versions of the EUPL (the "Licence"); You may not use this work except in
 * compliance with the Licence. You may obtain a copy of the Licence at: http://www.osor.eu/eupl/
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the Licence
 * is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the Licence for the specific language governing permissions and limitations under
 * the Licence.
 *
 * This product combines work with different licenses. See the "NOTICE" text file for details on the
 * various modules and licenses. The "NOTICE" text file is part of the distribution. Any derivative
 * works that you distribute must include a readable copy of the "NOTICE" text file.
*/

package at.gv.egiz.eaaf.core.impl.gui.velocity;

import org.apache.velocity.app.VelocityEngine;
import org.apache.velocity.runtime.RuntimeConstants;

/**
 * Gets a Velocity Engine.
 *
 * @author bzwattendorfer
 *
 */
public class VelocityProvider {

  private static VelocityEngine velocityEngine = null;

  /**
   * Gets velocityEngine from Classpath.
   *
   * @return VelocityEngine
   * @throws Exception In case of an error
   */
  public static VelocityEngine getClassPathVelocityEngine() throws Exception {
    if (velocityEngine == null) {
      velocityEngine = getBaseVelocityEngine();
      velocityEngine.setProperty(RuntimeConstants.RESOURCE_LOADER, "classpath");
      velocityEngine.setProperty("classpath.resource.loader.class",
          "org.apache.velocity.runtime.resource.loader.ClasspathResourceLoader");
      velocityEngine.init();

    }

    return velocityEngine;
  }

  /**
   * Gets VelocityEngine from File.
   *
   * @param rootPath File Path to template file
   * @return VelocityEngine
   * @throws Exception in case of an error
   */
  public static VelocityEngine getFileVelocityEngine(final String rootPath) throws Exception {
    if (velocityEngine == null) {
      velocityEngine = getBaseVelocityEngine();
      velocityEngine.setProperty(RuntimeConstants.RESOURCE_LOADER, "file");
      velocityEngine.setProperty("file.resource.loader.class",
          "org.apache.velocity.runtime.resource.loader.FileResourceLoader");
      velocityEngine.setProperty("file.resource.loader.path", rootPath);

      velocityEngine.init();

    }

    return velocityEngine;
  }

  /**
   * Gets a basic VelocityEngine.
   *
   * @return VelocityEngine
   */
  private static VelocityEngine getBaseVelocityEngine() {
    final VelocityEngine velocityEngine = new VelocityEngine();
    velocityEngine.setProperty(RuntimeConstants.INPUT_ENCODING, "UTF-8");
    return velocityEngine;
    
  }

}