Android Open Source - msf-spaces-sdk-android Data Object

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License

The source code is released under:

Apache License

Java Source Code

package de.imc.mirror.sdk.android;
// ww w . j  av  a  2 s.c  om
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.Serializable;

import org.jdom2.Attribute;
import org.jdom2.Element;
import org.jdom2.Namespace;
import org.jdom2.output.XMLOutputter;

import de.imc.mirror.sdk.CDMData;
import de.imc.mirror.sdk.cdm.CDMVersion;
import de.imc.mirror.sdk.android.cdm.CDMData_0_1;
import de.imc.mirror.sdk.android.cdm.CDMData_0_2;
import de.imc.mirror.sdk.android.cdm.CDMData_1_0;
import de.imc.mirror.sdk.android.cdm.CDMData_2_0;

/**
 * A data object represents an item published on a pubsub node of a space.
 * @author nmach, simon.schwantzer(at)im-c.de
 *
 */
public class DataObject implements Serializable, de.imc.mirror.sdk.DataObject{

  private static final long serialVersionUID = 1L;
  protected static final String CDTDATE = "cdt:date";
  protected static final String DATE = "date";
  protected static final String CDTPERSON = "cdt:person";
  protected static final String PERSON = "person";
  protected static final String PUBLISHER = "publisher";
  protected static final String ID = "id";
  protected static final String CDMVERSION = "cdmVersion";
  protected static final String MODELVERSION = "modelVersion";
  protected static final String CREATIONINFO = "creationInfo";
  protected static final String MIRROR_NSPREFIX = "mirror:";
  protected static final String CDM_0_1 = "0.1";
  protected static final String CDM_0_2 = "0.2";
  protected static final String CDM_1_0 = "1.0";
  
  private Element element;
  private String elementName;
  private CDMData cdmData;
  
  protected DataObject(DataObjectBuilder builder) {
    this.elementName = builder.elementName;
    this.element = builder.element;
    String cdmVersion = this.getCDMVersion();
    if (cdmVersion != null) {
      switch (CDMVersion.getVersionForString(cdmVersion)) {
      case CDM_0_1:
        cdmData = CDMData_0_1.verify(element).isEmpty() ? new CDMData_0_1(element) : null;
        break;
      case CDM_0_2:
        cdmData = CDMData_0_2.verify(element).isEmpty() ? new CDMData_0_2(element) : null;
        break;
      case CDM_1_0:
        cdmData = CDMData_1_0.verify(element).isEmpty() ? new CDMData_1_0(element) : null;
        break;
      case CDM_2_0:
        cdmData = CDMData_2_0.verify(element).isEmpty() ? new CDMData_2_0(element) : null;
        break;
      default:
        cdmData = null;
      }
    } else {
      cdmData = guessCDMVersion(element);
    }
  }
  
  /**
   * Tries to create a CDM object for the given data object element. Returns the highest CDM version which validates the element.  
   * @param element Root element of a data object.
   * @return CDM data object or <code>null</code> if no CDM version can be applied. 
   */
  private CDMData guessCDMVersion(Element element) {
    if (CDMData_2_0.verify(element).size() == 0) {
      return new CDMData_2_0(element);
    } else if (CDMData_1_0.verify(element).size() == 0) {
      return new CDMData_1_0(element);
    } else if (CDMData_0_2.verify(element).size() == 0) {
      return new CDMData_0_2(element);
    } else if (CDMData_0_1.verify(element).size() == 0) {
      return new CDMData_0_1(element);
    } else {
      return null;
    }
  }

  /**
   * Returns an XML string representing the data object.
   * @return The object as XML string.
   */
  @Override
  public String toString(){
    XMLOutputter out = new XMLOutputter();
    return out.outputString(element);
  }
  
  /**
   * @return The element name of the object.
   */
  public String getElementName(){
    return elementName;
  }
  
  /**
   * Returns the XML element for this data object.
   * @return XML element. This is the payload published on the pubsub node.
   */
  @Override
  public Element getElement(){
    return element;
  }
  
  /**
   * Returns the unique identifier of this data object provided by the CDM.
   * Refers to DataObject.getCDMData().getId();
   * @see CDMData#getId()
   * @return Data object identifier.
   */
  @Override
  public String getId() {
    return element.getAttributeValue(ID);
  }
  
  /**
   * @return The set cdmversion. If it wasn't set this method returns null.
   */
  public String getCDMVersion(){
    return element.getAttributeValue(CDMVERSION);    
  }
  
  /**
   * @return The set modelversion. If it wasn't set this method returns null.
   */
  public String getModelVersion(){
    return element.getAttributeValue(MODELVERSION);    
  }

  /**
   * Returns the common data model information for this object.
   * If no information is contained, i.e., the data object does not instantiate a
   * MIRROR data model, <code>null</code> will be returned.
   * @return CDM information container or <code>null</code> if no CDM data is available.
   */
  @Override
  public CDMData getCDMData() {
    return cdmData;
  }

  /**
   * Returns the namespace URI of the data object.
   * @return Namespace URI string.
   */
  @Override
  public String getNamespaceURI() {
    return element.getNamespaceURI();
  }

  /**
   * Checks if the data object claims to be an instance of a MIRROR data model.
   * A simple namespace comparison is applied, but no verification.
   * @return <code>true</code> if the XML object is from the MIRROR application namespace, otherwise <code>false</code>.
   */
  @Override
  public boolean isMIRRORDataObject() {
    return this.getNamespaceURI().startsWith(MIRROR_NSPREFIX);
  }

  /**
   * Returns the data model for the data object.
   * The returned model is not necessarily a MIRROR data model. No object verification is applied.
   * @return Model the data object claims to instantiate.
   */
  @Override
  public DataModel getDataModel(){
    Namespace ns = element.getNamespace("xsi");
    Attribute dataAttribute = element.getAttribute("schemaLocation", ns);
    DataModel result = null;
    if (dataAttribute != null){
      String schemaLocation = dataAttribute.getValue();
      String[] string = schemaLocation.split(" ");
      result = new DataModel(string[0], string[1]);
    }
    return result;
  }
  
  private synchronized void writeObject(ObjectOutputStream s) throws IOException{
    s.writeObject(element);
    s.writeObject(cdmData);
  }
  
  private synchronized void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException{
    this.element = (Element) s.readObject();
    this.cdmData = (CDMData) s.readObject();
    this.elementName = element.getName();
  }

}

Java Source Code List

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