/**
* Redistribution and use of this software and associated documentation
* ("Software"), with or without modification, are permitted provided
* that the following conditions are met:
*
* 1. Redistributions of source code must retain copyright
* statements and notices. Redistributions must also contain a
* copy of this document.
*
* 2. Redistributions in binary form must reproduce the
* above copyright notice, this list of conditions and the
* following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* 3. The name "Exolab" must not be used to endorse or promote
* products derived from this Software without prior written
* permission of Exoffice Technologies. For written permission,
* please contact info@exolab.org.
*
* 4. Products derived from this Software may not be called "Exolab"
* nor may "Exolab" appear in their names without prior written
* permission of Exoffice Technologies. Exolab is a registered
* trademark of Exoffice Technologies.
*
* 5. Due credit should be given to the Exolab Project
* (http://www.exolab.org/).
*
* THIS SOFTWARE IS PROVIDED BY EXOFFICE TECHNOLOGIES AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
* NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* EXOFFICE TECHNOLOGIES OR ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Copyright 2000-2001,2003 (C) Exoffice Technologies Inc. All Rights Reserved.
*/
package org.exolab.jms.selector.parser;
import org.exolab.jms.selector.Identifiers;
import org.exolab.jms.selector.Type;
import org.exolab.jms.selector.TypeMismatchException;
/**
* Utility class for performing type checking
*
* @version $Revision: 1.1 $ $Date: 2004/11/26 01:50:45 $
* @author <a href="mailto:tma@netspace.net.au">Tim Anderson</a>
* @see SelectorAST
* @see SelectorTreeParser
* @see Type
* @see TypeMismatchException
*/
final class TypeChecker {
/**
* Private constructor
*/
private TypeChecker() {
}
/**
* Checks the return type of an expression against the expected type
*
* @param node the expression node
* @param expected the expected type of the expression
* @throws TypeMismatchException if the return type doesn't match that
* expected
*/
public static void check(final SelectorAST node, final Type expected)
throws TypeMismatchException {
Type type = node.getReturnType();
if (type != expected && type != Type.UNDEFINED) {
String msg = "expecting a " + expected + " expression, found a "
+ type;
throw new TypeMismatchException(node.getContext(), msg);
}
}
/**
* Checks the return type of an expression against the expected type
*
* @param operator the expression operator
* @param node the expression node
* @param expected the expected type of the expression
* @throws TypeMismatchException if the return type doesn't match that
* expected
*/
public static void check(final String operator, final SelectorAST node,
final Type expected)
throws TypeMismatchException {
Type type = node.getReturnType();
if (type != expected && type != Type.UNDEFINED) {
String msg = "expecting a " + expected
+ " expression for operator " + operator + ", found a " + type;
throw new TypeMismatchException(node.getContext(), msg);
}
}
/**
* Checks the types of left and right hand sides of an expression against
* the expected type
*
* @param operator the expression operator
* @param left the left hand side of the expression
* @param right the right hand side of the expression
* @param expected the expected type of the expression
* @throws TypeMismatchException if a type doesn't match that expected
*/
public static void check(final String operator, final SelectorAST left,
final SelectorAST right, final Type expected)
throws TypeMismatchException {
check(operator, left, expected);
check(operator, right, expected);
}
/**
* Verifies if two expressions can be compared
*
* @param operator the comparison operator
* @param left the left hand side of the expression
* @param right the right hand side of the expression
* @throws TypeMismatchException if the expressions can't be compared
*/
public static void checkComparison(final String operator,
final SelectorAST left,
final SelectorAST right)
throws TypeMismatchException {
Type lhs = left.getReturnType();
Type rhs = right.getReturnType();
if (lhs == Type.UNDEFINED || rhs == Type.UNDEFINED) {
// can't evaluate this at parse time.
} else if (lhs == Type.STRING && rhs == Type.STRING) {
checkStringComparison(operator, left, right);
} else if ((lhs == Type.STRING && rhs != Type.STRING)
|| (lhs == Type.BOOLEAN && rhs != Type.BOOLEAN)
|| (lhs == Type.NUMERIC && rhs != Type.NUMERIC)) {
String msg = "expecting a " + lhs + " expression for operator "
+ operator + ", found a " + rhs;
throw new TypeMismatchException(right.getContext(), msg);
}
}
/**
* Verifies if two string expressions can be compared
*
* @param operator the comparison operator
* @param left the left hand side of the expression
* @param right the right hand side of the expression
* @throws TypeMismatchException if the expressions can't be compared
*/
public static void checkStringComparison(final String operator,
final SelectorAST left,
final SelectorAST right)
throws TypeMismatchException {
if (left.getType() == SelectorTokenTypes.IDENT
&& right.getType() == SelectorTokenTypes.STRING_LITERAL) {
checkIdentifierComparison(left, right);
} else if (left.getType() == SelectorTokenTypes.STRING_LITERAL
&& right.getType() == SelectorTokenTypes.IDENT) {
checkIdentifierComparison(right, left);
}
}
/**
* Verifies that an identifier may be compared to a string literal
*
* @param identifier the identifier
* @param literal the string literal
* @throws TypeMismatchException if the expressions can't be compared
*/
public static void checkIdentifierComparison(final SelectorAST identifier,
final SelectorAST literal)
throws TypeMismatchException {
if (identifier.getText().equals(Identifiers.JMS_DELIVERY_MODE)) {
String value = literal.getText();
if (!value.equals(Identifiers.PERSISTENT)
&& !value.equals(Identifiers.NON_PERSISTENT)) {
String msg = "Cannot compare JMSDeliveryMode with '"
+ value + "'";
throw new TypeMismatchException(identifier.getContext(), msg);
}
}
}
} //-- TypeChecker