org.exist.xquery
Class BinaryOp
java.lang.Object
org.exist.xquery.AbstractExpression
org.exist.xquery.PathExpr
org.exist.xquery.BinaryOp
- All Implemented Interfaces:
- CompiledExpression, CompiledXQuery, Expression
- Direct Known Subclasses:
- GeneralComparison, LogicalOp, NodeComparison, OpNumeric
- public abstract class BinaryOp
- extends PathExpr
Methods inherited from class org.exist.xquery.PathExpr |
accept, add, add, addPath, addPredicate, dump, dump, getASTNode, getCardinality, getContext, getDependencies, getDocumentSet, getExpression, getLastExpression, getLength, getLiteralValue, getSource, isValid, replaceLastExpression, reset, resetState, setContext, setPrimaryAxis, setSource, toString |
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
BinaryOp
public BinaryOp(XQueryContext context)
returnsType
public int returnsType()
- Description copied from interface:
Expression
- The static return type of the expression.
This method should return one of the type constants defined in class
Type
. If the return type cannot be determined
statically, return Type.ITEM.
- Specified by:
returnsType
in interface Expression
- Overrides:
returnsType
in class PathExpr
getLeft
public Expression getLeft()
getRight
public Expression getRight()
setLeft
public void setLeft(Expression expr)
setRight
public void setRight(Expression expr)
setContextDocSet
public void setContextDocSet(DocumentSet contextSet)
- Specified by:
setContextDocSet
in interface Expression
- Overrides:
setContextDocSet
in class AbstractExpression
analyze
public void analyze(AnalyzeContextInfo contextInfo)
throws XPathException
- Description copied from interface:
Expression
- Statically analyze the expression and its subexpressions.
During the static analysis phase, the query engine can detect
unknown variables and some type errors.
- Specified by:
analyze
in interface Expression
- Overrides:
analyze
in class PathExpr
- Throws:
XPathException
eval
public abstract Sequence eval(Sequence contextSequence,
Item contextItem)
throws XPathException
- Description copied from interface:
Expression
- Evaluate the expression represented by this object.
Depending on the context in which this expression is executed,
either the context sequence, the context item or both of them may
be set. An implementing class should know how to handle this.
The general contract is as follows: if the
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.
- Specified by:
eval
in interface Expression
- Overrides:
eval
in class PathExpr
- Throws:
XPathException
Copyright (C) Wolfgang Meier. All rights reserved.