/**
* Enact all of the value definition changes, then call the group listener (if there is one).
*
* @param groupUpdateAction the group action to enact value changes on.
* @param configurationSource will be passed to the {@link
* GroupChangeListener#onChange(ConfigurationSource)} method giving it a chance to lookup
* other values at runtime.
* @throws GroupConfigurationException if any problem occurs with the value updates or listener
* invocation.
*/
public void enactGroupChange(
GroupChangeAction groupUpdateAction, ConfigurationSource configurationSource) {
ValueDefinitionGroup valueDefinitionGroup = groupUpdateAction.getGroup();
List<ValueChangeAction> actionList = groupUpdateAction.getActionList();
List<ConfigurationException> valueUpdateErrors = new ArrayList<ConfigurationException>();
Object semaphore = valueDefinitionGroup.getSemaphore();
if (semaphore == null) {
// Semaphore must be set to something
semaphore = new Object();
}
/*
* Lock on the semaphore, providing an opportunity to atomically update a group of variables.
*/
synchronized (semaphore) {
/*
* Make the value updates by calling the listeners. Make an attempt to update all values, in case
*/
for (ValueChangeAction valueUpdateAction : actionList) {
try {
enactValueChange(valueUpdateAction);
} catch (ConfigurationException e) {
valueUpdateErrors.add(e);
}
}
if (!valueUpdateErrors.isEmpty()) {
throw new GroupConfigurationException(
valueDefinitionGroup.getName(), Phase.VALUE_ASSIGNMENT, valueUpdateErrors);
}
/*
* We are clear to notify of the change
*/
GroupChangeListener changeListener = valueDefinitionGroup.getChangeListener();
if (changeListener != null) {
try {
changeListener.onChange(configurationSource);
} catch (RuntimeException e) {
throw new GroupConfigurationException(
valueDefinitionGroup.getName(), Phase.LISTENER_INVOCATION, e);
}
}
}
}
/**
* Prepares a {@link ValueChangeAction} for each {@link ValueDefinition} in the specified group.
*
* @param valueDefinitionGroup the group to prepare value changes for
* @param configurationSource the source from which to resolve the values of this group
* @return the group change action
* @throws GroupConfigurationException if there is a problem retrieving values for one or more of
* the {@link ValueDefinition}s in the group
*/
public GroupChangeAction prepareGroupChange(
ValueDefinitionGroup valueDefinitionGroup, ConfigurationSource configurationSource) {
Collection<ValueDefinition<?, ?>> valueDefinitionList = valueDefinitionGroup.getValues();
List<ValueChangeAction> updateActions =
new ArrayList<ValueChangeAction>(valueDefinitionList.size());
List<ConfigurationException> valueResolveErrors = new ArrayList<ConfigurationException>();
try {
for (ValueDefinition<?, ?> valueDefinition : valueDefinitionList) {
ValueChangeAction valueChangeAction =
prepareValueChange(valueDefinition, configurationSource);
updateActions.add(valueChangeAction);
}
} catch (ConfigurationException e) {
valueResolveErrors.add(e);
}
if (!valueResolveErrors.isEmpty()) {
throw new GroupConfigurationException(
valueDefinitionGroup.getName(), Phase.VALUE_DISCOVERY, valueResolveErrors);
}
return new GroupChangeAction(valueDefinitionGroup, updateActions);
}