package com.webobjects.eoaccess;
import org.apache.log4j.Logger;
import com.webobjects.foundation.NSArray;
import com.webobjects.foundation.NSComparator;
import com.webobjects.foundation.NSComparator.ComparisonException;
import com.webobjects.foundation.NSForwardException;
import er.extensions.eof.ERXEntityFKConstraintOrder;
import er.extensions.eof.ERXEntityOrder;
/**
* <p>EODatabaseContext delegate to order adaptor operations by FK constraints. This prevents most ordering
* operations on databases like MS SQL that do not support deferred constraints like a real database.
* The easiest way to use this is:</p>
* <pre>
* ERXDatabaseContextMulticastingDelegate.addDefaultDelegate(new ERXEntityDependencyOrderingDelegate());
* </pre>
* To turn this on for a Wonder application, just set this property:
* <pre>
* com.webobjects.eoaccess.ERXEntityDependencyOrderingDelegate.active = true
* </pre>
*
* @author chill
*/
public class ERXEntityDependencyOrderingDelegate {
public static final String ERXEntityDependencyOrderingDelegateActiveKey = "com.webobjects.eoaccess.ERXEntityDependencyOrderingDelegate.active";
protected NSComparator adaptorOpComparator;
private static Logger logger = Logger.getLogger(ERXEntityDependencyOrderingDelegate.class);
public ERXEntityDependencyOrderingDelegate() {
super();
}
/**
* Lazy creation of an EOAdaptorOpComparator that uses a list of entities that are in FK dependency order.
* Enable DEBUG logging to see the ordered list of entity names.
*
* @see com.webobjects.eoaccess.EOAdaptorOpComparator
* @return EOAdaptorOpComparator that uses a list of entities that are in FK dependency order
*/
protected NSComparator adaptorOpComparator() {
if (adaptorOpComparator == null) {
ERXEntityFKConstraintOrder constraintOrder = new ERXEntityFKConstraintOrder();
NSComparator entityOrderingComparator = new ERXEntityOrder.EntityInsertOrderComparator(constraintOrder);
try {
NSArray<EOEntity> entityOrdering = constraintOrder.allEntities().sortedArrayUsingComparator(entityOrderingComparator);
NSArray<String> entityNameOrdering = (NSArray<String>)entityOrdering.valueForKey("name");
if (logger.isDebugEnabled()) {
logger.debug("Entity ordering:\n " + entityNameOrdering.componentsJoinedByString("\n"));
}
adaptorOpComparator = new ERXAdaptorOpComparator(entityNameOrdering);
}
catch (ComparisonException e) {
throw NSForwardException._runtimeExceptionForThrowable(e);
}
}
return adaptorOpComparator;
}
/**
* EODatabaseContext.Delegate method to order a list of adaptor operations. Uses adaptorOpComparator() for the ordering.
*
* @param aDatabaseContext EODatabaseContext that the operations will be executed in
* @param adaptorOperations list of operations to execute
* @param adaptorChannel the adaptor channel these will be executed on
*
* @see com.webobjects.eoaccess.EODatabaseContext.Delegate#databaseContextWillPerformAdaptorOperations(EODatabaseContext,NSArray,EOAdaptorChannel)
* @return operations in an order that should avoid FK constraint violations
*/
public NSArray<EOAdaptorOperation> databaseContextWillPerformAdaptorOperations(EODatabaseContext aDatabaseContext,
NSArray<EOAdaptorOperation> adaptorOperations,
EOAdaptorChannel adaptorChannel) {
try {
return adaptorOperations.sortedArrayUsingComparator(adaptorOpComparator());
}
catch (com.webobjects.foundation.NSComparator.ComparisonException e) {
throw NSForwardException._runtimeExceptionForThrowable(e);
}
}
public boolean databaseContextShouldHandleDatabaseException(EODatabaseContext dbCtxt, Throwable exception)
{
// Useful for debugging
if ( ! (exception instanceof EOGeneralAdaptorException))
{
logger.error("Unexpected non-EOGeneralAdaptorException exception", exception);
}
return true;
}
}