de.hybris.platform.jalo

Interface Item.ItemConstraint

Enclosing class:

Item

public static interface Item.ItemConstraint

Interface for implementing transaction aware consistency checks using the item method Item.checkConstraint(ItemConstraint). Using this interface consistency check code is wrapped in an object and executed depending upon the enclosing transaction state. If there is no active transaction running the code is executed immediately by calling assertConstraint(Item). If it throws an exception the method undoChanges(Item) is called to let the enclosing code restore the previous state. In case there is a running transaction the code is not executed by registered at the transaction. It is being executed by calling assertConstraint(Item) upon transaction commit just before the actual changes are committed permanently. If one of the registered constrains throws an exception the transaction is rolled back - so undoChanges(Item) is not called in this case! An example:

        public void do( String arg )
        {
                final String prev = getProperty("blah");
                setProperty( "blah", arg );
                checkConstraint(
                        new ItemConstraint()
                        {
                                public void assertConstraint(Item item) throws ConsistencyCheckException
                                {
                                        if( ((MyItem)item).getProperty("blubb") == null && ((MyItem)item).getProperty("blah") == null )
                                                throw new ConsistencyCheckException("should never happen", 0 );
                                }
                                public void undoChanges( Item item )
                                {
                                        ((MyItem)item).setProperty("blah", prev );
                                }
                        }
                );
        }
 

See Also:

Item.checkConstraint(de.hybris.platform.jalo.Item.ItemConstraint)

Method Summary

Modifier and Type	Method and Description
void	assertConstraint(Item item) Called to perform the actual constraint checking.
void	undoChanges(Item item) Called only if there is no enclosing transaction to rollback changes automatically: this method should restore the item state prior the change which triggered this constraint.

Method Detail

assertConstraint

void assertConstraint(Item item)
               throws ConsistencyCheckException

Called to perform the actual constraint checking.

Parameters:

item - the item from which Item.checkConstraint(de.hybris.platform.jalo.Item.ItemConstraint) has been called.

Throws:

ConsistencyCheckException - to signal that the constraint is violated

undoChanges

void undoChanges(Item item)

Called only if there is no enclosing transaction to rollback changes automatically: this method should restore the item state prior the change which triggered this constraint.

Parameters:

item - the item from which Item.checkConstraint(de.hybris.platform.jalo.Item.ItemConstraint) has been called.