Bug 152430 Key can modify to empty string
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/EmbeddedImageHandle.java
import java.io.UnsupportedEncodingException;
import org.eclipse.birt.report.model.api.activity.SemanticException;
import org.eclipse.birt.report.model.api.elements.structures.EmbeddedImage;
import org.eclipse.birt.report.model.api.util.StringUtil;
import org.eclipse.birt.report.model.core.Module;
import org.eclipse.birt.report.model.elements.ImageItem;
import org.eclipse.birt.report.model.elements.Library;
/**
 * Represents the handle of an embedded image. The class gives the name and type
 * of the image. Used when an image element {@link ImageItem}gives a name. Each
 * embedded image has the following properties:
 * 
 * <p>
 * <dl>
 * <dt><strong>Name </strong></dt>
 * <dd>an embedded image has a unique and required name, so the image item can
 * use the image name to identify an embedded image.</dd>
 * 
 * <dt><strong>Type </strong></dt>
 * <dd>an embedded image has a choice and required type: bmp, gif, png or
 * x-png.</dd>
 * 
 * <dt><strong>Data </strong></dt>
 * <dd>value of the image data in Base64 encoding.</dd>
 * </dl>
 *  
 */
public class EmbeddedImageHandle extends StructureHandle
{
	/**