| java.lang.Object
 org.josql.expressions.Expression
org.josql.expressions.ValueExpression
org.josql.expressions.ArithmeticExpression
| ArithmeticExpression | | public class ArithmeticExpression extends ValueExpression (Code) | | Represents the arithmetic expressions: *, +, /, - and %.
It should be noted that ALL numbers in JoSQL are represented as double values, this
allows for easy arithmetic operations without the fear of losing precision or casting
issues.
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| ADDITION | | final public static int ADDITION(Code) | | |
| DIVIDE | | final public static int DIVIDE(Code) | | |
| MODULUS | | final public static int MODULUS(Code) | | |
| MULTIPLY | | final public static int MULTIPLY(Code) | | |
| SUBTRACT | | final public static int SUBTRACT(Code) | | |
| evaluate | | public Object evaluate(Object o, Query q) throws QueryExecutionException(Code) | | Evaulate this expression. Apart from the special cases the LHS and RHS must evaluate
to an instance of java.lang.Number otherwise a QueryExecutionException is
thrown.
Special cases:
- If the type of the expression is + and either LHS or RHS are NOT numbers
then the String concatentation of them both are returned.
This works the same as in Java.
- If the type of the expression is / and the RHS is 0 then 0 is returned.
Parameters:
o - The object to perform the expression on.
Parameters:
q - The Query object. The result of the expression, see the "special cases" for the exceptions to what wouldbe the intuitive result.
throws:
QueryExecutionException - If an error occurs during processing. |
| getExpectedReturnType | | public Class getExpectedReturnType(Query q) throws QueryParseException(Code) | | Return the expected return type. This just returns the result of calling this
method on the LHS.
Parameters:
q - The Query object. The expected return type class.
throws:
QueryParseException - If something goes wrong in determining the return type. |
| getType | | public int getType()(Code) | | |
| isTrue | | public boolean isTrue(Object o, Query q) throws QueryExecutionException(Code) | | Determine whether this arithmetic expression evaluates to true.
Whilst this seems a little bizarre this method is needed to allow
artithmetic expressions to be used in the columns part of the SELECT.
Thus the following could be performed:
SELECT 10 + 20
FROM java.lang.Object
The rules are as follows:
Parameters:
o - The object to perform the expression on.
Parameters:
q - The Query object. As according to the rules above.
throws:
QueryExecutionException - If something goes wrong during the evaluation of the expression. |
| setType | | public void setType(int t)(Code) | | |
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