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The reason why I prefer this one is because it is generic and can be reused for confirmation dialogs. You want to open some sort of dialog before doing any action, just chain it.
Prototype ChainedAction
Here's a code snippet from the ChainedAction prototype. One problem I ran into is that I somehow have to stop or pause the chain execution, when waiting for user input. I solved this by introducing two interfaces ChainedActionCallback and DeferredAction. If one of the action sin the chain is a DeferredAction we sto pthe execution and the Action will have to call proceed on the callback to resume execution.
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public class ChainedAction<D extends ChainedActionDefinition> extends AbstractAction<ChainedActionDefinition> implements ChainedActionCallback {
private final Item item;
private final Context context;
private final ComponentProvider componentProvider;
private Iterator<Action> it;
public ChainedAction(D definition, final Item item, ComponentProvider componentProvider) {
super(definition);
this.item = item;
this.componentProvider = componentProvider;
this.context = new SimpleContext();
}
private void prepareExecution() throws ActionExecutionException {
Collection<Action> actions = new LinkedList<Action>();
for (ActionDefinition actionDefinition : getDefinition().getActions()) {
Action action = createAction(actionDefinition, item, context, this);
actions.add(action);
}
this.it = actions.iterator();
}
@Override
public void execute() throws ActionExecutionException {
prepareExecution();
executeNext();
}
private void executeNext() throws ActionExecutionException {
while(it.hasNext()) {
Action action = it.next();
action.execute();
if (action instanceof DeferredAction) {
break;
}
}
}
private Action createAction(ActionDefinition actionDefinition, Object... args) throws ActionExecutionException {
Class<? extends Action> implementationClass = actionDefinition.getImplementationClass();
if (implementationClass == null) {
throw new ActionExecutionException("No action class set for action: " + actionDefinition.getName());
}
Object[] combinedParameters = new Object[args.length + 1];
combinedParameters[0] = actionDefinition;
System.arraycopy(args, 0, combinedParameters, 1, args.length);
try {
return componentProvider.newInstance(implementationClass, combinedParameters);
} catch (MgnlInstantiationException e) {
throw new ActionExecutionException("Could not instantiate action class for action: " + actionDefinition.getName(), e);
}
}
@Override
public void proceed() {
try {
executeNext();
} catch (ActionExecutionException e) {
e.printStackTrace(); //To change body of catch statement use File | Settings | File Templates.
}
}
@Override
public void abort() {
}
} |
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