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java.lang.Object
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+--net.sf.saxon.expr.ComputedExpression
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+--net.sf.saxon.expr.BinaryExpression
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+--net.sf.saxon.expr.ValueComparison
ValueComparison: a boolean expression that compares two atomic values for equals, not-equals, greater-than or less-than. Implements the operators eq, ne, lt, le, gt, ge
| Field Summary | |
protected Expression |
operand0
|
protected Expression |
operand1
|
protected int |
operator
|
| Fields inherited from class net.sf.saxon.expr.ComputedExpression |
locationId, staticProperties |
| Fields inherited from interface net.sf.saxon.expr.Expression |
EVALUATE_METHOD, ITERATE_METHOD, PROCESS_METHOD |
| Constructor Summary | |
ValueComparison(Expression p1,
int op,
Expression p2)
Create a relational expression identifying the two operands and the operator |
|
| Method Summary | |
Expression |
analyze(StaticContext env,
ItemType contextItemType)
Type-check the expression |
protected static boolean |
compare(AtomicValue v1,
int op,
AtomicValue v2,
AtomicComparer collator)
Compare two atomic values, using a specified operator and collation |
int |
computeCardinality()
Determine the static cardinality. |
void |
display(int level,
NamePool pool,
java.io.PrintStream out)
Diagnostic print of expression structure |
protected java.lang.String |
displayOperator()
|
boolean |
effectiveBooleanValue(XPathContext context)
Evaluate the expression in a boolean context |
boolean |
equals(java.lang.Object other)
Is this expression the same as another expression? |
Item |
evaluateItem(XPathContext context)
Evaluate the expression in a given context |
ItemType |
getItemType()
Determine the data type of the expression |
int |
hashCode()
get HashCode for comparing two expressions. |
protected static boolean |
isCommutative(int operator)
|
java.util.Iterator |
iterateSubExpressions()
Get the immediate subexpressions of this expression |
Expression |
promote(PromotionOffer offer)
Promote this expression if possible |
Expression |
simplify(StaticContext env)
Simplify an expression |
| Methods inherited from class java.lang.Object |
clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait |
| Field Detail |
protected Expression operand0
protected Expression operand1
protected int operator
| Constructor Detail |
public ValueComparison(Expression p1,
int op,
Expression p2)
p1 - the left-hand operandop - the operator, as a token returned by the Tokenizer (e.g. Token.LT)p2 - the right-hand operand| Method Detail |
public Expression analyze(StaticContext env,
ItemType contextItemType)
throws XPathException
analyze in interface Expressionanalyze in class net.sf.saxon.expr.BinaryExpressionenv - the static context of the expressioncontextItemType - the static type of "." at the point where this expression is invoked.
The parameter is set to null if it is known statically that the context item will be undefined.
If the type of the context item is not known statically, the argument is set to
Type.ITEM_TYPE
XPathException
public boolean effectiveBooleanValue(XPathContext context)
throws XPathException
effectiveBooleanValue in interface ExpressioneffectiveBooleanValue in class ComputedExpressioncontext - the given context for evaluation
XPathException - if any dynamic error occurs evaluating the
expression
protected static boolean compare(AtomicValue v1,
int op,
AtomicValue v2,
AtomicComparer collator)
throws DynamicError
v1 - the first operandop - the operator, as defined by constants such as Token.FEQ or
Token.FLTv2 - the second operandcollator - the Collator to be used when comparing strings
DynamicError - if the values are not comparable
public Item evaluateItem(XPathContext context)
throws XPathException
evaluateItem in interface ExpressionevaluateItem in class ComputedExpressioncontext - the given context for evaluation
XPathException - if any dynamic error occurs evaluating the
expressionpublic ItemType getItemType()
public Expression simplify(StaticContext env)
throws XPathException
simplify in interface Expressionsimplify in class ComputedExpressionXPathException - if an error is discovered during expression
rewriting
public Expression promote(PromotionOffer offer)
throws XPathException
promote in interface Expressionpromote in class ComputedExpressionoffer - details of the offer, for example the offer to move
expressions that don't depend on the context to an outer level in
the containing expression
XPathException - if any error is detectedpublic java.util.Iterator iterateSubExpressions()
iterateSubExpressions in interface ExpressioniterateSubExpressions in class ComputedExpressionpublic int computeCardinality()
computeCardinality in class ComputedExpressionprotected static boolean isCommutative(int operator)
public boolean equals(java.lang.Object other)
equals in class java.lang.Objectpublic int hashCode()
hashCode in class java.lang.Object
public void display(int level,
NamePool pool,
java.io.PrintStream out)
level - indentation level for this expressionpool - NamePool used to expand any names appearing in the expressionout - Output destinationprotected java.lang.String displayOperator()
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