/**
* Get the DataContentHandler for this DataHandler:
*
* <p>If a DataContentHandlerFactory is set, use it. Otherwise look for an object to serve DCH in
* the following order:
*
* <p>1) if a factory is set, use it
*
* <p>2) if a CommandMap is set, use it
*
* <p>3) use the default CommandMap
*
* <p>In any case, wrap the real DataContentHandler with one of our own to handle any missing
* cases, fill in defaults, and to ensure that we always have a non-null DataContentHandler.
*
* @return the requested DataContentHandler
*/
private synchronized DataContentHandler getDataContentHandler() {
// make sure the factory didn't change
if (factory != oldFactory) {
oldFactory = factory;
factoryDCH = null;
dataContentHandler = null;
transferFlavors = emptyFlavors;
}
if (dataContentHandler != null) return dataContentHandler;
String simpleMT = getBaseType();
if (factoryDCH == null && factory != null)
factoryDCH = factory.createDataContentHandler(simpleMT);
if (factoryDCH != null) dataContentHandler = factoryDCH;
if (dataContentHandler == null) {
if (dataSource != null)
dataContentHandler = getCommandMap().createDataContentHandler(simpleMT, dataSource);
else dataContentHandler = getCommandMap().createDataContentHandler(simpleMT);
}
// getDataContentHandler always uses these 'wrapper' handlers
// to make sure it returns SOMETHING meaningful...
if (dataSource != null)
dataContentHandler = new DataSourceDataContentHandler(dataContentHandler, dataSource);
else
dataContentHandler = new ObjectDataContentHandler(dataContentHandler, object, objectMimeType);
return dataContentHandler;
}
/**
* Sets the DataContentHandlerFactory. The DataContentHandlerFactory is called first to find
* DataContentHandlers. The DataContentHandlerFactory can only be set once.
*
* <p>If the DataContentHandlerFactory has already been set, this method throws an Error.
*
* @param newFactory the DataContentHandlerFactory
* @exception Error if the factory has already been defined.
* @see javax.activation.DataContentHandlerFactory
*/
public static synchronized void setDataContentHandlerFactory(
DataContentHandlerFactory newFactory) {
if (factory != null) throw new Error("DataContentHandlerFactory already defined");
SecurityManager security = System.getSecurityManager();
if (security != null) {
try {
// if it's ok with the SecurityManager, it's ok with me...
security.checkSetFactory();
} catch (SecurityException ex) {
// otherwise, we also allow it if this code and the
// factory come from the same class loader (e.g.,
// the JAF classes were loaded with the applet classes).
if (DataHandler.class.getClassLoader() != newFactory.getClass().getClassLoader()) throw ex;
}
}
factory = newFactory;
}
