com.saxonica.bytecode
Class ValueComparisonCompiler

java.lang.Object
  com.saxonica.bytecode.ExpressionCompiler
      com.saxonica.bytecode.ToBooleanCompiler
          com.saxonica.bytecode.ValueComparisonCompiler

public class ValueComparisonCompiler
extends ToBooleanCompiler

Generate code for a ValueComparison

Constructor Summary

ValueComparisonCompiler()

Method Summary

static void	compile(CompilerService compiler, Expression expression, Expression[] operands, int op, AtomicComparer comparer, boolean toItem) This method handles both compileToBoolean and compileToItem.
void	compileToBoolean(CompilerService compiler, Expression expression) Generate bytecode to evaluate the ValueComparison as a boolean value Precondition: none.
void	compileToItem(CompilerService compiler, Expression expression) Generate bytecode to evaluate the expression as an Item Precondition: none.
static int	translateOperator(int op)

Methods inherited from class com.saxonica.bytecode.ToBooleanCompiler

compileToIterator, compileToPush

Methods inherited from class com.saxonica.bytecode.ExpressionCompiler

allocateStatic, compileItemFromInt, compileItemFromString, compileToLoop, compileToPrimitive, generateMethod, getConfiguration, handleEmptyStringResult, setConfiguration, throwXPathException, throwXPathException, unboxItem, verify, visitAnnotation, visitLineNumber

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ValueComparisonCompiler

public ValueComparisonCompiler()

Method Detail

compileToItem

public void compileToItem(CompilerService compiler,
                          Expression expression)
                   throws CannotCompileException

Generate bytecode to evaluate the expression as an Item Precondition: none. Postcondition: the stack contains either an item (the result of the expression), or null (representing an empty sequence).

Overrides:

compileToItem in class ToBooleanCompiler

Parameters:

compiler - the compiler service

expression - the expression to be compiled

Throws:

CannotCompileException

compileToBoolean

public void compileToBoolean(CompilerService compiler,
                             Expression expression)
                      throws CannotCompileException

Generate bytecode to evaluate the ValueComparison as a boolean value Precondition: none. Postcondition: the stack contains an boolean value representing the result of the expression

Specified by:

compileToBoolean in class ExpressionCompiler

Parameters:

compiler - the compiler service

expression - the expression to be compiled

Throws:

CannotCompileException

compile

public static void compile(CompilerService compiler,
                           Expression expression,
                           Expression[] operands,
                           int op,
                           AtomicComparer comparer,
                           boolean toItem)
                    throws CannotCompileException

This method handles both compileToBoolean and compileToItem. The difference is that in some circumstances compileToItem returns an empty sequence when compileToBoolean returns false;

Parameters:

compiler - the compiler service

expression - the expression to be compiled

operands -

op - the Operator

comparer - the AtomicComparer used to compare the two atomic values

toItem - true if compiling to an Item rather than to a boolean

Throws:

CannotCompileException - if the expression cannot be compiled

translateOperator

public static int translateOperator(int op)