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java.lang.Objectorg.exist.xquery.AbstractExpression
Field Summary |
Fields inherited from interface org.exist.xquery.Expression |
DOT_TEST, EXPRESSION_ID_INVALID, IGNORE_CONTEXT, IN_PREDICATE, IN_UPDATE, IN_WHERE_CLAUSE, NO_CONTEXT_ID, SINGLE_STEP_EXECUTION |
Constructor Summary | |
AbstractExpression(XQueryContext context)
|
Method Summary | |
void |
accept(ExpressionVisitor visitor)
Start traversing the expression tree using the specified ExpressionVisitor . |
Sequence |
eval(Sequence contextSequence)
Evaluate the expression represented by this object. |
abstract Sequence |
eval(Sequence contextSequence,
Item contextItem)
Evaluate the expression represented by this object. |
XQueryAST |
getASTNode()
Returns the XQueryAST node from which this expression
has been constructed by the parser. |
int |
getCardinality()
The default cardinality is Cardinality.EXACTLY_ONE . |
DocumentSet |
getContextDocSet()
|
int |
getContextId()
|
int |
getDependencies()
Returns Dependency.DEFAULT_DEPENDENCIES . |
int |
getExpressionId()
Returns an id which uniquely identifies this expression within the compiled expression tree of the query. |
void |
resetState()
Called to inform an expression that it should reset to its initial state. |
abstract int |
returnsType()
The static return type of the expression. |
void |
setASTNode(XQueryAST ast)
|
void |
setContextDocSet(DocumentSet contextSet)
|
void |
setPrimaryAxis(int axis)
|
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface org.exist.xquery.Expression |
analyze, dump |
Constructor Detail |
public AbstractExpression(XQueryContext context)
Method Detail |
public int getExpressionId()
Expression
getExpressionId
in interface Expression
Expression.EXPRESSION_ID_INVALID
public int getContextId()
getContextId
in interface Expression
public Sequence eval(Sequence contextSequence) throws XPathException
Expression
eval
in interface Expression
XPathException
public abstract Sequence eval(Sequence contextSequence, Item contextItem) throws XPathException
Expression
Dependency.CONTEXT_ITEM
bit is set in the bit field returned by Expression.getDependencies()
, the eval method will
be called once for every item in the context sequence. The contextItem
parameter will be set to the current item. Otherwise, the eval method will only be called
once for the whole context sequence and contextItem will be null.
eXist tries to process the entire context set in one, single step whenever
possible. Thus, most classes only expect context to contain a list of
nodes which represents the current context of the expression.
The position() function in XPath is an example for an expression,
which requires both, context sequence and context item to be set.
The context sequence might be a node set, a sequence of atomic values or a single
node or atomic value.
eval
in interface Expression
contextSequence
- the current context sequence.contextItem
- a single item, taken from context. This defines the item,
the expression should work on.
XPathException
public abstract int returnsType()
Expression
Type
. If the return type cannot be determined
statically, return Type.ITEM.
returnsType
in interface Expression
public void resetState()
Expression
resetState
in interface Expression
public int getCardinality()
Cardinality.EXACTLY_ONE
.
getCardinality
in interface Expression
public int getDependencies()
Dependency.DEFAULT_DEPENDENCIES
.
getDependencies
in interface Expression
Expression.getDependencies()
public void setPrimaryAxis(int axis)
setPrimaryAxis
in interface Expression
public void setContextDocSet(DocumentSet contextSet)
setContextDocSet
in interface Expression
public DocumentSet getContextDocSet()
getContextDocSet
in interface Expression
public void accept(ExpressionVisitor visitor)
Expression
ExpressionVisitor
.
accept
in interface Expression
visitor
- public void setASTNode(XQueryAST ast)
setASTNode
in interface Expression
public XQueryAST getASTNode()
Expression
XQueryAST
node from which this expression
has been constructed by the parser. This node contains location information
(line number and column) important for error reports.
getASTNode
in interface Expression
|
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