package org.argeo.cms.ui.workbench.internal.useradmin.providers;
   
   import java.util.HashMap;
   import java.util.Map;
   
   import javax.transaction.Status;
   import javax.transaction.UserTransaction;
   
   import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  import org.argeo.cms.CmsException;
  import org.argeo.cms.ui.workbench.WorkbenchUiPlugin;
  import org.eclipse.ui.AbstractSourceProvider;
  import org.eclipse.ui.ISources;
  
  /** Observe and notify UI on UserTransaction state changes */
  public class UserTransactionProvider extends AbstractSourceProvider {
  	private final static Log log = LogFactory
  			.getLog(UserTransactionProvider.class);
  
  	public final static String TRANSACTION_STATE = WorkbenchUiPlugin.PLUGIN_ID
  			+ ".userTransactionState";
  	public final static String STATUS_ACTIVE = "status.active";
  	public final static String STATUS_NO_TRANSACTION = "status.noTransaction";
  
  	/* DEPENDENCY INJECTION */
  	private UserTransaction userTransaction;
  
  	@Override
  	public String[] getProvidedSourceNames() {
  		return new String[] { TRANSACTION_STATE };
  	}
  
  	@Override
  	public Map<String, String> getCurrentState() {
  		Map<String, String> currentState = new HashMap<String, String>(1);
  		currentState.put(TRANSACTION_STATE, getInternalCurrentState());
  		return currentState;
  	}
  
  	@Override
  	public void dispose() {
  	}
  
  	private String getInternalCurrentState() {
  		try {
  			String transactionState;
  			if (userTransaction.getStatus() == Status.STATUS_NO_TRANSACTION)
  				transactionState = STATUS_NO_TRANSACTION;
  			else
  				// if (userTransaction.getStatus() == Status.STATUS_ACTIVE)
  				transactionState = STATUS_ACTIVE;
  			return transactionState;
  		} catch (Exception e) {
  			throw new CmsException("Unable to begin transaction", e);
  		}
  	}
  
  	/** Publishes the ability to notify a state change */
  	public void fireTransactionStateChange() {
  		try {
  			fireSourceChanged(ISources.WORKBENCH, TRANSACTION_STATE,
  					getInternalCurrentState());
  		} catch (Exception e) {
  			log.warn("Cannot fire transaction state change event. Caught exception: "
  					+ e.getClass().getCanonicalName() + " - " + e.getMessage());
  		}
  	}
  
  	/* DEPENDENCY INJECTION */
  	public void setUserTransaction(UserTransaction userTransaction) {
  		this.userTransaction = userTransaction;
  	}
  }