UpdateAllQuerypublic class UpdateAllQuery extends ModifyAllQuery | PUBLIC:
A Query Class used to perform a bulk update using TopLink's expression framework.
This class is provided to help optimize performance. It can be used in place
of reading in all the objects to be changed and issuing single updates per
instance. With this approach a single SQL UPDATE statement can be issued and
then, based on the Expression provided, any objects in the cache that are
effected by the update can be invalidated.
Notes:
- By default, if a UOW is being used, this query will be deferred until the UOW commits.
- UpdateAllQuery does not support foreign key updates
unless the relationship is 1-1 (without back pointers.)
Example of Usage: Adding an area code.
UpdateAllQuery updateQuery = new UpdateAllQuery(Employee.class);
updateQuery.setSelectionCriteria(eb.get("areaCode").isNull());
updateQuery.addUpdate(eb.get("areaCode"), "613");
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| Fields Summary |
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| protected HashMap | m_updateClauses |
| Constructors Summary |
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public UpdateAllQuery()PUBLIC:
Constructs a default update all query.
super();
| public UpdateAllQuery(Class referenceClass)PUBLIC:
Constructs an update all query for the Class type specified.
super(referenceClass);
| public UpdateAllQuery(Class referenceClass, Expression selectionCriteria)PUBLIC:
Constructs an update all query for the specified Class type and selection criteria.
super(referenceClass, selectionCriteria);
| public UpdateAllQuery(Class referenceClass, ExpressionBuilder expressionBuilder)PUBLIC:
Constructs an update all query for the Class type specified and the given
ExpressionBuilder. This sets the default builder which is used for all associated
expressions in the query.
super(referenceClass);
this.defaultBuilder = expressionBuilder;
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| Methods Summary |
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| public void | addUpdate(oracle.toplink.essentials.expressions.Expression field, java.lang.Object value)PUBLIC:
Adds the update (SET) clause to the query. Uses default ExpressionBuilder.
addUpdateInternal(field, value);
| | public void | addUpdate(java.lang.String attributeName, java.lang.Object value)PUBLIC:
Adds the update (SET) clause to the query. Uses default ExpressionBuilder.
addUpdateInternal(attributeName, value);
| | public void | addUpdate(oracle.toplink.essentials.expressions.Expression field, oracle.toplink.essentials.expressions.Expression value)PUBLIC:
Adds the update (SET) clause to the query. This method ensures that
the builder has the session and reference class set for both given Expressions.
Uses default ExpressionBuilder.
addUpdateInternal(field, value);
| | public void | addUpdate(java.lang.String attributeName, oracle.toplink.essentials.expressions.Expression value)PUBLIC:
Adds the update (SET) clause to the query. Uses default ExpressionBuilder.
addUpdateInternal(attributeName, value);
| | protected void | addUpdateInternal(java.lang.Object fieldObject, java.lang.Object valueObject)INTERNAL:
if(fieldObject == null) {
throw QueryException.updateAllQueryAddUpdateFieldIsNull(this);
}
if(m_updateClauses == null) {
m_updateClauses = new HashMap();
}
m_updateClauses.put(fieldObject, valueObject);
| | public java.lang.Object | executeDatabaseQuery()INTERNAL:
Issue the SQL to the database and then merge into the cache.
If we are within a UoW, the merge to the cache must not be done until
the UoW merges into the parent. The UoW will trigger the merge to occur
at the correct time and will ensure the cache setting is set to none at
that time.
result = getQueryMechanism().updateAll();// fire the SQL to the database
mergeChangesIntoSharedCache();
return result;
| | public java.util.HashMap | getUpdateClauses()INTERNAL:
Return the updates stored for an update all query
return m_updateClauses;
| | protected void | initializeQuerySpecificDefaultBuilder()INTERNAL:
Initialize the expression builder which should be used for this query. If
there is a where clause, use its expression builder.
If after this method defaultBuilder is still null,
then initializeDefaultBuilder method will generate and cache it.
super.initializeQuerySpecificDefaultBuilder();
if(this.defaultBuilder == null && m_updateClauses != null) {
Iterator it = m_updateClauses.values().iterator();
while(it.hasNext() ) {
Object value = it.next();
if(value != null) {
if(value instanceof Expression) {
Expression valueExpression = (Expression)value;
this.defaultBuilder = valueExpression.getBuilder();
if(this.defaultBuilder != null) {
return;
}
}
}
}
it = m_updateClauses.keySet().iterator();
while(it.hasNext() ) {
Object field = it.next();
if(field instanceof Expression) {
Expression fieldExpression = (Expression)field;
this.defaultBuilder = fieldExpression.getBuilder();
if(this.defaultBuilder != null) {
return;
}
}
}
}
| | public boolean | isUpdateAllQuery()INTERNAL:
Return true if this is an update all query.
return true;
| | protected void | prepare()INTERNAL:
super.prepare();// will tell the query mechanism to prepare itself as well.
Class referenceClass = getReferenceClass();
// Check the reference class, must be set
if (referenceClass == null) {
throw QueryException.referenceClassMissing(this);
}
// Check the descriptor is set, if not try to get it from the session
if (getDescriptor() == null) {
ClassDescriptor desc = getSession().getDescriptor(referenceClass);
if (desc == null) {
throw QueryException.descriptorIsMissing(referenceClass, this);
}
setDescriptor(desc);
}
ClassDescriptor descriptor = getDescriptor();
// Check the descriptor for an aggregate
if (descriptor.isAggregateDescriptor()) {
throw QueryException.aggregateObjectCannotBeDeletedOrWritten(descriptor, this);
}
// Check that the update statement is set. That is the bare minimum,
// the user can execute this query without a selection criteria though.
if ((getUpdateClauses() == null || getUpdateClauses().isEmpty()) && isExpressionQuery()) {
throw QueryException.updateStatementsNotSpecified();
}
getQueryMechanism().prepareUpdateAll();
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