|
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||||
java.lang.Objectnet.sf.saxon.expr.Expression
net.sf.saxon.expr.Literal
public class Literal
A Literal is an expression whose value is constant: it is a class that implements the Expression
interface as a wrapper around a Value. This may derive from an actual literal in an XPath expression
or query, or it may be the result of evaluating a constant subexpression such as true() or xs:date('2007-01-16')
| Field Summary |
|---|
| Fields inherited from class net.sf.saxon.expr.Expression |
|---|
EFFECTIVE_BOOLEAN_VALUE, EVALUATE_METHOD, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, MAX_SEQUENCE_LENGTH, MAX_STRING_LENGTH, PROCESS_METHOD, PUSH_SELECTION, staticProperties, UNBOUNDED_LOWER, UNBOUNDED_UPPER, WATCH_METHOD |
| Constructor Summary | |
|---|---|
Literal(Value value)
Create a literal as a wrapper around a Value |
|
| Method Summary | |
|---|---|
PathMap.PathMapNodeSet |
addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
Add a representation of this expression to a PathMap. |
int |
computeCardinality()
Determine the cardinality |
int |
computeSpecialProperties()
Compute the static properties of this expression (other than its type). |
Expression |
copy()
Copy an expression. |
boolean |
effectiveBooleanValue(XPathContext context)
Get the effective boolean value of the expression. |
boolean |
equals(Object obj)
Determine whether two literals are equal, when considered as expressions. |
CharSequence |
evaluateAsString(XPathContext context)
Evaluate an expression as a String. |
Item |
evaluateItem(XPathContext context)
Evaluate as a singleton item (or empty sequence). |
void |
evaluatePendingUpdates(XPathContext context,
PendingUpdateList pul)
Evaluate an updating expression, adding the results to a Pending Update List. |
void |
explain(ExpressionPresenter out)
Diagnostic print of expression structure. |
int |
getDependencies()
Determine which aspects of the context the expression depends on. |
IntegerValue[] |
getIntegerBounds()
For an expression that returns an integer or a sequence of integers, get a lower and upper bound on the values of the integers that may be returned, from static analysis. |
ItemType |
getItemType(TypeHierarchy th)
Determine the data type of the items in the expression, if possible |
Value |
getValue()
Get the value represented by this Literal |
int |
hashCode()
Return a hash code to support the equals() function |
static boolean |
isAtomic(Expression exp)
Test whether the literal wraps an atomic value. |
static boolean |
isConstantBoolean(Expression exp,
boolean value)
Test if a literal represents the boolean value true |
static boolean |
isConstantOne(Expression exp)
Test if a literal represents the integer value 1 |
static boolean |
isEmptySequence(Expression exp)
Test whether the literal explicitly wraps an empty sequence. |
boolean |
isSubtreeExpression()
Determine whether the expression can be evaluated without reference to the part of the context document outside the subtree rooted at the context node. |
boolean |
isVacuousExpression()
Determine whether this is a vacuous expression as defined in the XQuery update specification |
SequenceIterator<? extends Item> |
iterate()
Return an Iterator to iterate over the values of a sequence. |
SequenceIterator<? extends Item> |
iterate(XPathContext context)
Return an Iterator to iterate over the values of a sequence. |
static Literal |
makeEmptySequence()
Make an empty-sequence literal |
static Literal |
makeLiteral(Value value)
Create a literal as a wrapper around a Value (factory method) |
Expression |
optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
Optimize an expression |
void |
process(XPathContext context)
Process the value as an instruction, without returning any tail calls |
Expression |
simplify(ExpressionVisitor visitor)
Simplify an expression |
String |
toString()
The toString() method for an expression attempts to give a representation of the expression in an XPath-like form, but there is no guarantee that the syntax will actually be true XPath. |
Expression |
typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
TypeCheck an expression |
| Methods inherited from class java.lang.Object |
|---|
clone, finalize, getClass, notify, notifyAll, wait, wait, wait |
| Constructor Detail |
|---|
public Literal(Value value)
value - the value of this literal| Method Detail |
|---|
public static Literal makeLiteral(Value value)
value - the value of this literal
public static Literal makeEmptySequence()
public Value getValue()
public Expression simplify(ExpressionVisitor visitor)
simplify in class Expressionvisitor - an expression visitor
public Expression typeCheck(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
typeCheck in class Expressionvisitor - an expression visitorcontextItemType - 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
public final Expression optimize(ExpressionVisitor visitor,
ExpressionVisitor.ContextItemType contextItemType)
optimize in class Expressionvisitor - an expression visitorcontextItemType - 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
public ItemType getItemType(TypeHierarchy th)
getItemType in class Expressionth - The TypeHierarchy. Can be null if the target is an AtomicValue.
public int computeCardinality()
computeCardinality in class ExpressionStaticProperty.ALLOWS_ZERO_OR_ONE,
StaticProperty.EXACTLY_ONE, StaticProperty.ALLOWS_ONE_OR_MORE,
StaticProperty.ALLOWS_ZERO_OR_MOREpublic int computeSpecialProperties()
StaticProperty.NON_CREATIVE.
computeSpecialProperties in class ExpressionStaticProperty.NON_CREATIVEpublic IntegerValue[] getIntegerBounds()
getIntegerBounds in class Expressionpublic boolean isVacuousExpression()
isVacuousExpression in class Expressionpublic Expression copy()
copy in class Expression
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
PathMap.PathMapNodeSet pathMapNodeSet)
addToPathMap in class ExpressionpathMap - the PathMap to which the expression should be addedpathMapNodeSet - the set of nodes within the path map
public final int getDependencies()
getDependencies in class Expression
public SequenceIterator<? extends Item> iterate(XPathContext context)
throws XPathException
iterate in class Expressioncontext - supplies the context for evaluation
XPathException - if any dynamic error occurs evaluating the
expression
public SequenceIterator<? extends Item> iterate()
throws XPathException
XPathException - if any dynamic error occurs evaluating the
expression
public Item evaluateItem(XPathContext context)
throws XPathException
evaluateItem in class Expressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expression
public void process(XPathContext context)
throws XPathException
process in class Expressioncontext - The dynamic context, giving access to the current node,
the current variables, etc.
XPathException - if a dynamic error occurs
public CharSequence evaluateAsString(XPathContext context)
throws XPathException
Expression
evaluateAsString in class Expressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expression
public boolean effectiveBooleanValue(XPathContext context)
throws XPathException
effectiveBooleanValue in class Expressioncontext - The context in which the expression is to be evaluated
XPathException - if any dynamic error occurs evaluating the
expression
public void evaluatePendingUpdates(XPathContext context,
PendingUpdateList pul)
throws XPathException
evaluatePendingUpdates in class Expressioncontext - the XPath dynamic evaluation contextpul - the pending update list to which the results should be written
XPathException - if evaluation failspublic boolean equals(Object obj)
equals in class Objectobj - the other expression
public int hashCode()
hashCode in class Objectpublic String toString()
toString in class Expressionpublic void explain(ExpressionPresenter out)
explain in class Expressionout - the expression presenter used to display the structurepublic static boolean isAtomic(Expression exp)
exp - an expression
public static boolean isEmptySequence(Expression exp)
exp - an expression
public static boolean isConstantBoolean(Expression exp,
boolean value)
exp - an expressionvalue - true or false
public static boolean isConstantOne(Expression exp)
exp - an expression
public boolean isSubtreeExpression()
isSubtreeExpression in class Expression
|
|||||||||
| PREV CLASS NEXT CLASS | FRAMES NO FRAMES | ||||||||
| SUMMARY: NESTED | FIELD | CONSTR | METHOD | DETAIL: FIELD | CONSTR | METHOD | ||||||||