oracle.toplink.essentials.internal.expressions.ForUpdateOfClause Maven / Gradle / Ivy
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package oracle.toplink.essentials.internal.expressions;
import java.util.*;
import oracle.toplink.essentials.expressions.*;
import oracle.toplink.essentials.queryframework.ObjectBuildingQuery;
/**
* Purpose:Represents The FOR UPDATE OF fine-grained pessimistically
* locking clause.
* @author Stephen McRitchie
* @since Oracle Toplink 10g AS
*/
public class ForUpdateOfClause extends ForUpdateClause {
protected Vector lockedExpressions;
public ForUpdateOfClause() {
}
public void addLockedExpression(ObjectExpression expression) {
getLockedExpressions().addElement(expression);
}
public Vector getLockedExpressions() {
if (lockedExpressions == null) {
lockedExpressions = oracle.toplink.essentials.internal.helper.NonSynchronizedVector.newInstance();
}
return lockedExpressions;
}
public boolean isForUpdateOfClause() {
return true;
}
public boolean isReferenceClassLocked() {
if (lockedExpressions == null) {
return false;
}
// Normally the expressionBuilder is stored first but not necessarily
// when a child ForUpdateOfClause is built for a nested query, or if a
//user made this clause.
for (int i = 0; i < lockedExpressions.size(); i++) {
if (((Expression)lockedExpressions.elementAt(i)).isExpressionBuilder()) {
return true;
}
}
return false;
}
public void setLockedExpressions(Vector lockedExpressions) {
this.lockedExpressions = lockedExpressions;
}
public void setLockMode(short lockMode) {
this.lockMode = lockMode;
}
/**
* INTERNAL:
* Prints the as of clause for an expression inside of the FROM clause.
*/
public void printSQL(ExpressionSQLPrinter printer, SQLSelectStatement statement) {
// assert(lockedExpressions != null && lockedExpressions.size() > 0);
// assert( getLockMode() == ObjectBuildingQuery.LOCK ||
// getLockMode() == ObjectBuildingQuery.LOCK_NOWAIT);
ExpressionBuilder clonedBuilder = statement.getBuilder();
printer.printString(printer.getSession().getPlatform().getSelectForUpdateOfString());
printer.setIsFirstElementPrinted(false);
for (Enumeration enumtr = getLockedExpressions().elements(); enumtr.hasMoreElements();) {
ObjectExpression next = (ObjectExpression)enumtr.nextElement();
// Neccessary as this was determined in query framework.
next = (ObjectExpression)next.rebuildOn(clonedBuilder);
next.writeForUpdateOfFields(printer, statement);
}
if (lockMode == ObjectBuildingQuery.LOCK_NOWAIT) {
printer.printString(printer.getSession().getPlatform().getSelectForUpdateNoWaitString());
}
}
}