org.exist.xquery.update
Class Update
java.lang.Object
org.exist.xquery.AbstractExpression
org.exist.xquery.update.Modification
org.exist.xquery.update.Update
- All Implemented Interfaces:
- Expression
- public class Update
- extends Modification
- Author:
- wolf
Methods inherited from class java.lang.Object |
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Update
public Update(XQueryContext context,
Expression select,
Expression value)
eval
public 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
- Specified by:
eval
in class AbstractExpression
- Throws:
XPathException
dump
public void dump(ExpressionDumper dumper)
- Description copied from interface:
Expression
- Write a diagnostic dump of the expression to the passed
ExpressionDumper
.
- Parameters:
dumper
- the expression dumper to write to
toString
public java.lang.String toString()
Copyright (C) Wolfgang Meier. All rights reserved.