Change.java

/**
 * Copyright 2013 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Eclipse Public License version 1.0, available at
 * http://www.eclipse.org/legal/epl-v10.html
 */

package org.jboss.forge.addon.resource.transaction;

import org.jboss.forge.addon.resource.Resource;
import org.jboss.forge.addon.resource.events.ResourceEvent;

/**
 * A {@link Change} object contains references to the original and the modified resource enlisted in a
 * {@link ResourceTransaction}
 * 
 * @author <a href="ggastald@redhat.com">George Gastaldi</a>
 */
public interface Change
{
   /**
    * The description of this change (if any)
    */
   String getDescription();

   /**
    * @return The original {@link Resource}
    */
   Resource<?> getOriginalResource();

   /**
    * @return The modified {@link Resource}
    */
   Resource<?> getModifiedResource();

   /**
    * @return The {@link ResourceEvent} that originated this {@link Change}
    */
   ResourceEvent getEvent();
}

ResourceFactoryTransactionDecorator.java

/**
 * Copyright 2013 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Eclipse Public License version 1.0, available at
 * http://www.eclipse.org/legal/epl-v10.html
 */

package org.jboss.forge.addon.resource.transaction;

import javax.annotation.Priority;
import javax.decorator.Decorator;
import javax.decorator.Delegate;
import javax.inject.Inject;

import org.jboss.forge.addon.resource.Resource;
import org.jboss.forge.addon.resource.ResourceFactory;

/**
 * Adds orthogonal transaction features to the {@link ResourceFactory}
 * 
 * @author <a href="ggastald@redhat.com">George Gastaldi</a>
 */
@Priority(0)
@Decorator
public abstract class ResourceFactoryTransactionDecorator implements ResourceFactory
{

   @Inject
   @Delegate
   ResourceFactory delegate;

   private volatile boolean enabled;

   @Override
   public <E, T extends Resource<E>> T create(Class<T> type, E underlyingResource)
   {
      T result = delegate.create(type, underlyingResource);
      if (enabled)
      {
         // Wrap the resource
      }
      return result;
   }

   void setEnabled(boolean enabled)
   {
      this.enabled = enabled;
   }
}

ResourceTransaction.java

/**
 * Copyright 2013 Red Hat, Inc. and/or its affiliates.
 *
 * Licensed under the Eclipse Public License version 1.0, available at
 * http://www.eclipse.org/legal/epl-v10.html
 */

package org.jboss.forge.addon.resource.transaction;

import java.io.Closeable;
import java.util.Set;

/**
 * A {@link ResourceTransaction} manages changes to a group of resources
 * 
 * @author <a href="ggastald@redhat.com">George Gastaldi</a>
 */
public interface ResourceTransaction extends Closeable
{
   /**
    * Starts a transaction. It does nothing if the transaction was already started. It throws an
    * {@link IllegalStateException} if the transaction was closed
    */
   public void start();

   /**
    * Applies every change in the {@link Set} returned by {@link ResourceTransaction#getChangeSet()}
    */
   public void commit();

   /**
    * Discards this transaction and the associated changes with it
    */
   public void rollback();

   /**
    * The changes associated with this transaction.
    * 
    * @return a mutable {@link Set} with the changes that were introduced so far
    */
   public Set<Change> getChangeSet();
}