/*
    * Copyright 2005-2008 The Kuali Foundation
    *
    *
    * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php
   *
   * 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.kuali.rice.kew.xml.export;
  
  import java.io.IOException;
  import java.io.StringWriter;
  import java.util.Iterator;
  import java.util.List;
  
  import org.jdom.Document;
  import org.jdom.Element;
  import org.jdom.output.Format;
  import org.jdom.output.Format.TextMode;
  import org.jdom.output.XMLOutputter;
  import org.kuali.rice.kew.exception.WorkflowRuntimeException;
  import org.kuali.rice.kew.export.ExportDataSet;
  import org.kuali.rice.kew.service.KEWServiceLocator;
  import org.kuali.rice.kew.xml.XmlConstants;
  import org.kuali.rice.kns.exception.ExportNotSupportedException;
  import org.springframework.beans.factory.BeanInitializationException;
  
  
  /**
   * An implementation of the XmlExporterService which can be configured with a set of
   * services that know how to export various pieces of the {@link ExportDataSet} to XML.
   *
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public class XmlExporterServiceImpl implements XmlExporterService, XmlConstants {
  
      private List serviceOrder;
  
      public byte[] export(ExportDataSet dataSet) {
          if (dataSet == null) {
              throw new IllegalArgumentException("Xml Exporter cannot handle NULL data.");
          }
          Element rootElement = new Element(DATA_ELEMENT, WORKFLOW_NAMESPACE);
          rootElement.addNamespaceDeclaration(SCHEMA_NAMESPACE);
          rootElement.setAttribute(SCHEMA_LOCATION_ATTR, WORKFLOW_SCHEMA_LOCATION, SCHEMA_NAMESPACE);
          Document document = new Document(rootElement);
          for (Iterator iterator = serviceOrder.iterator(); iterator.hasNext();) {
              XmlExporter exporter = (XmlExporter)KEWServiceLocator.getService((String) iterator.next());
              appendIfNotEmpty(rootElement, exporter.export(dataSet));
          }
  
          // TODO: KULRICE-4420 - this needs cleanup
          Format f;
          if (!dataSet.getEdocLites().isEmpty() || !dataSet.getStyles().isEmpty()) {
              f = Format.getRawFormat();
              f.setExpandEmptyElements(false);
              f.setTextMode(Format.TextMode.PRESERVE);
          } else {
              f = Format.getPrettyFormat();
          }
          XMLOutputter outputer = new XMLOutputter(f);
          StringWriter writer = new StringWriter();
          try {
              outputer.output(document, writer);
          } catch (IOException e) {
              throw new WorkflowRuntimeException("Could not write XML data export.", e);
          }
          return writer.toString().getBytes();
      }
  
      private void appendIfNotEmpty(Element parent, Element child) {
          if (child != null) {
              parent.addContent(child);
          }
      }
  
      public void setServiceOrder(List serviceOrder) throws BeanInitializationException {
          this.serviceOrder = serviceOrder;
      }
  
  }