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java.lang.Object | +--net.sf.saxon.expr.ComputedExpression | +--net.sf.saxon.expr.BinaryExpression | +--net.sf.saxon.expr.GeneralComparison
GeneralComparison: a boolean expression that compares two expressions for equals, not-equals, greater-than or less-than. This implements the operators =, !=, <, >, etc.
Field Summary | |
protected boolean |
backwardsCompatible
|
protected AtomicComparer |
comparer
|
protected Expression |
operand0
|
protected Expression |
operand1
|
protected int |
operator
|
protected int |
singletonOperator
|
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 | |
GeneralComparison(Expression p0,
int op,
Expression p1)
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 a1,
int operator,
AtomicValue a2,
AtomicComparer comparer,
boolean backwardsCompatible,
XPathContext context)
Compare two atomic values |
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 |
protected GeneralComparison |
getInverseComparison()
|
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 int singletonOperator
protected AtomicComparer comparer
protected boolean backwardsCompatible
protected Expression operand0
protected Expression operand1
protected int operator
Constructor Detail |
public GeneralComparison(Expression p0, int op, Expression p1)
p0
- the left-hand operandop
- the operator, as a token returned by the Tokenizer (e.g. Token.LT)p1
- the right-hand operandMethod Detail |
public int computeCardinality()
computeCardinality
in class net.sf.saxon.expr.BinaryExpression
public Expression analyze(StaticContext env, ItemType contextItemType) throws XPathException
analyze
in interface Expression
analyze
in class net.sf.saxon.expr.BinaryExpression
env
- 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 Item evaluateItem(XPathContext context) throws XPathException
evaluateItem
in interface Expression
evaluateItem
in class ComputedExpression
context
- the given context for evaluation
XPathException
- if any dynamic error occurs evaluating the
expressionpublic boolean effectiveBooleanValue(XPathContext context) throws XPathException
effectiveBooleanValue
in interface Expression
effectiveBooleanValue
in class ComputedExpression
context
- the given context for evaluation
XPathException
- if any dynamic error occurs evaluating the
expressionprotected static boolean compare(AtomicValue a1, int operator, AtomicValue a2, AtomicComparer comparer, boolean backwardsCompatible, XPathContext context) throws XPathException
XPathException
public ItemType getItemType()
protected GeneralComparison getInverseComparison()
protected java.lang.String displayOperator()
displayOperator
in class net.sf.saxon.expr.BinaryExpression
public Expression simplify(StaticContext env) throws XPathException
simplify
in interface Expression
simplify
in class ComputedExpression
XPathException
- if an error is discovered during expression
rewritingpublic Expression promote(PromotionOffer offer) throws XPathException
promote
in interface Expression
promote
in class ComputedExpression
offer
- 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 Expression
iterateSubExpressions
in class ComputedExpression
protected static boolean isCommutative(int operator)
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
public 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 destination
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