betweenoperatornode.java

一个Java持久层类库

package org.hibernate.hql.ast.tree;

import org.hibernate.type.Type;
import org.hibernate.Hibernate;
import antlr.SemanticException;

/**
 * Contract for nodes representing logcial BETWEEN (ternary) operators.
 *
 * @author Steve Ebersole
 */
public class BetweenOperatorNode extends SqlNode implements OperatorNode {

	public void initialize() throws SemanticException {
		Node fixture = getFixtureOperand();
		if ( fixture == null ) {
			throw new SemanticException( "fixture operand of a between operator was null" );
		}
		Node low = getLowOperand();
		if ( low == null ) {
			throw new SemanticException( "low operand of a between operator was null" );
		}
		Node high = getHighOperand();
		if ( high == null ) {
			throw new SemanticException( "high operand of a between operator was null" );
		}
		check( fixture, low, high );
		check( low, high, fixture );
		check( high, fixture, low );
	}

	public Type getDataType() {
		// logic operators by definition resolve to boolean.
		return Hibernate.BOOLEAN;
	}

	public Node getFixtureOperand() {
		return ( Node ) getFirstChild();
	}

	public Node getLowOperand() {
		return ( Node ) getFirstChild().getNextSibling();
	}

	public Node getHighOperand() {
		return ( Node ) getFirstChild().getNextSibling().getNextSibling();
	}

	private void check(Node check, Node first, Node second) {
		if ( ExpectedTypeAwareNode.class.isAssignableFrom( check.getClass() ) ) {
			Type expectedType = null;
			if ( SqlNode.class.isAssignableFrom( first.getClass() ) ) {
				expectedType = ( ( SqlNode ) first ).getDataType();
			}
			if ( expectedType == null && SqlNode.class.isAssignableFrom( second.getClass() ) ) {
				expectedType = ( ( SqlNode ) second ).getDataType();
			}
			( ( ExpectedTypeAwareNode ) check ).setExpectedType( expectedType );
		}
	}
}