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BinaryArithmeticOperatorNode.javaAPI DocHibernate 3.2.56883Thu Jun 08 16:04:46 BST 2006org.hibernate.hql.ast.tree

BinaryArithmeticOperatorNode

public class BinaryArithmeticOperatorNode extends AbstractSelectExpression implements DisplayableNode, BinaryOperatorNode
Nodes which represent binary arithmetic operators.
author
Gavin King

Fields Summary
Constructors Summary
Methods Summary
public org.hibernate.type.TypegetDataType()
Figure out the type of the binary expression by looking at the types of the operands. Sometimes we don't know both types, if, for example, one is a parameter.

		if ( super.getDataType() == null ) {
			super.setDataType( resolveDataType() );
		}
		return super.getDataType();
	
public java.lang.StringgetDisplayText()

		return "{dataType=" + getDataType() + "}";
	
public NodegetLeftHandOperand()
Retrieves the left-hand operand of the operator.

return
The left-hand operand

		return ( Node ) getFirstChild();
	
public NodegetRightHandOperand()
Retrieves the right-hand operand of the operator.

return
The right-hand operand

		return ( Node ) getFirstChild().getNextSibling();
	
public voidinitialize()

		Node lhs = getLeftHandOperand();
		Node rhs = getRightHandOperand();
		if ( lhs == null ) {
			throw new SemanticException( "left-hand operand of a binary operator was null" );
		}
		if ( rhs == null ) {
			throw new SemanticException( "right-hand operand of a binary operator was null" );
		}

		Type lhType = ( lhs instanceof SqlNode ) ? ( ( SqlNode ) lhs ).getDataType() : null;
		Type rhType = ( rhs instanceof SqlNode ) ? ( ( SqlNode ) rhs ).getDataType() : null;

		if ( ExpectedTypeAwareNode.class.isAssignableFrom( lhs.getClass() ) && rhType != null ) {
			Type expectedType = null;
			// we have something like : "? [op] rhs"
			if ( isDateTimeType( rhType ) ) {
				// more specifically : "? [op] datetime"
				//      1) if the operator is MINUS, the param needs to be of
				//          some datetime type
				//      2) if the operator is PLUS, the param needs to be of
				//          some numeric type
				expectedType = getType() == HqlSqlTokenTypes.PLUS ? Hibernate.DOUBLE : rhType;
			}
			else {
				expectedType = rhType;
			}
			( ( ExpectedTypeAwareNode ) lhs ).setExpectedType( expectedType );
		}
		else if ( ParameterNode.class.isAssignableFrom( rhs.getClass() ) && lhType != null ) {
			Type expectedType = null;
			// we have something like : "lhs [op] ?"
			if ( isDateTimeType( lhType ) ) {
				// more specifically : "datetime [op] ?"
				//      1) if the operator is MINUS, we really cannot determine
				//          the expected type as either another datetime or
				//          numeric would be valid
				//      2) if the operator is PLUS, the param needs to be of
				//          some numeric type
				if ( getType() == HqlSqlTokenTypes.PLUS ) {
					expectedType = Hibernate.DOUBLE;
				}
			}
			else {
				expectedType = lhType;
			}
			( ( ExpectedTypeAwareNode ) rhs ).setExpectedType( expectedType );
		}
	
private booleanisDateTimeType(org.hibernate.type.Type type)

		if ( type == null ) {
			return false;
		}
		return java.util.Date.class.isAssignableFrom( type.getReturnedClass() ) ||
	           java.util.Calendar.class.isAssignableFrom( type.getReturnedClass() );
	
private org.hibernate.type.TyperesolveDataType()

		// TODO : we may also want to check that the types here map to exactly one column/JDBC-type
		//      can't think of a situation where arithmetic expression between multi-column mappings
		//      makes any sense.
		Node lhs = getLeftHandOperand();
		Node rhs = getRightHandOperand();
		Type lhType = ( lhs instanceof SqlNode ) ? ( ( SqlNode ) lhs ).getDataType() : null;
		Type rhType = ( rhs instanceof SqlNode ) ? ( ( SqlNode ) rhs ).getDataType() : null;
		if ( isDateTimeType( lhType ) || isDateTimeType( rhType ) ) {
			return resolveDateTimeArithmeticResultType( lhType, rhType );
		}
		else {
			if ( lhType == null ) {
				if ( rhType == null ) {
					// we do not know either type
					return Hibernate.DOUBLE; //BLIND GUESS!
				}
				else {
					// we know only the rhs-hand type, so use that
					return rhType;
				}
			}
			else {
				if ( rhType == null ) {
					// we know only the lhs-hand type, so use that
					return lhType;
				}
				else {
					if ( lhType==Hibernate.DOUBLE || rhType==Hibernate.DOUBLE ) return Hibernate.DOUBLE;
					if ( lhType==Hibernate.FLOAT || rhType==Hibernate.FLOAT ) return Hibernate.FLOAT;
					if ( lhType==Hibernate.BIG_DECIMAL || rhType==Hibernate.BIG_DECIMAL ) return Hibernate.BIG_DECIMAL;
					if ( lhType==Hibernate.BIG_INTEGER || rhType==Hibernate.BIG_INTEGER ) return Hibernate.BIG_INTEGER;
					if ( lhType==Hibernate.LONG || rhType==Hibernate.LONG ) return Hibernate.LONG;
					if ( lhType==Hibernate.INTEGER || rhType==Hibernate.INTEGER ) return Hibernate.INTEGER;
					return lhType;
				}
			}
		}
	
private org.hibernate.type.TyperesolveDateTimeArithmeticResultType(org.hibernate.type.Type lhType, org.hibernate.type.Type rhType)

		// here, we work under the following assumptions:
		//      ------------ valid cases --------------------------------------
		//      1) datetime + {something other than datetime} : always results
		//              in a datetime ( db will catch invalid conversions )
		//      2) datetime - datetime : always results in a DOUBLE
		//      3) datetime - {something other than datetime} : always results
		//              in a datetime ( db will catch invalid conversions )
		//      ------------ invalid cases ------------------------------------
		//      4) datetime + datetime
		//      5) {something other than datetime} - datetime
		//      6) datetime * {any type}
		//      7) datetime / {any type}
		//      8) {any type} / datetime
		// doing so allows us to properly handle parameters as either the left
		// or right side here in the majority of cases
		boolean lhsIsDateTime = isDateTimeType( lhType );
		boolean rhsIsDateTime = isDateTimeType( rhType );

		// handle the (assumed) valid cases:
		// #1 - the only valid datetime addition synatx is one or the other is a datetime (but not both)
		if ( getType() == HqlSqlTokenTypes.PLUS ) {
			// one or the other needs to be a datetime for us to get into this method in the first place...
			return lhsIsDateTime ? lhType : rhType;
		}
		else if ( getType() == HqlSqlTokenTypes.MINUS ) {
			// #3 - note that this is also true of "datetime - :param"...
			if ( lhsIsDateTime && !rhsIsDateTime ) {
				return lhType;
			}
			// #2
			if ( lhsIsDateTime && rhsIsDateTime ) {
				return Hibernate.DOUBLE;
			}
		}
		return null;
	
public voidsetScalarColumnText(int i)

		ColumnHelper.generateSingleScalarColumn( this, i );