java.lang.Object
- net.sf.saxon.expr.Expression
- - net.sf.saxon.expr.FunctionCall
  - - net.sf.saxon.functions.SystemFunction
    - - net.sf.saxon.functions.Id

All Implemented Interfaces:

java.io.Serializable, javax.xml.transform.SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, org.xml.sax.Locator
```
public class Id
extends SystemFunction
```
The XPath id() function XPath 2.0 version: accepts any sequence as the first parameter; each item in the sequence is taken as an IDREFS value, that is, a space-separated list of ID values. Also accepts an optional second argument to identify the target document, this defaults to the context node.

See Also:

Serialized Form

Field Summary
- Fields inherited from class net.sf.saxon.functions.SystemFunction
  operation
- Fields inherited from class net.sf.saxon.expr.FunctionCall
  argument
- Fields inherited from class net.sf.saxon.expr.Expression
  EVALUATE_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, staticProperties

Constructor Summary

Constructors
Constructor Description

Id()

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`PathMap.PathMapNodeSet`	`addToPathMap(PathMap pathMap, PathMap.PathMapNodeSet pathMapNodeSet)`	Add a representation of a doc() call or similar function to a PathMap.
`void`	`checkArguments(ExpressionVisitor visitor)`	Static analysis: prevent sorting of the argument
`int`	`computeSpecialProperties()`	Get the static properties of this expression (other than its type).
`static SequenceIterator`	`getIdMultiple(DocumentInfo doc, SequenceIterator idrefs)`	Get an iterator over the nodes that have an id equal to one of the values is a set of whitespace separated strings
`static SequenceIterator`	`getIdSingle(DocumentInfo doc, java.lang.String idrefs)`	Get an iterator over the nodes that have an id equal to one of the values is a whitespace separated string
`SequenceIterator`	`iterate(XPathContext context)`	Evaluate the function to return an iteration of selected nodes.
`Expression`	`preEvaluate(ExpressionVisitor visitor)`	preEvaluate: this method suppresses compile-time evaluation by doing nothing
`Expression`	`simplify(ExpressionVisitor visitor)`	Simplify: add a second implicit argument, the context document

Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, computeCardinality, copy, getDetails, getErrorCodeForTypeErrors, getItemType, getRequiredType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault

Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, equals, explain, getArguments, getDisplayName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, promote, replaceSubExpression, setArguments, setFunctionName, simplifyArguments, toString, typeCheck

Methods inherited from class net.sf.saxon.expr.Expression
adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, display, doPromotion, dynamicError, effectiveBooleanValue, evaluateAsString, evaluateItem, evaluatePendingUpdates, explain, findParentOf, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getExecutable, getHostLanguage, getImplementationMethod, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, implementsStaticTypeCheck, isUpdatingExpression, iterateEvents, markTailFunctionCalls, process, resetLocalStaticProperties, setContainer, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Id
```
public Id()
```
- Method Detail
  - simplify
```
public Expression simplify(ExpressionVisitor visitor)
                    throws XPathException
```
    Simplify: add a second implicit argument, the context document
    
    Overrides:
    
    simplify in class FunctionCall
    
    Parameters:
    
    visitor - an expression visitor
    
    Returns:
    
    the simplified expression
    
    Throws:
    
    XPathException - if an error is discovered during expression rewriting
  - checkArguments
```
public void checkArguments(ExpressionVisitor visitor)
                    throws XPathException
```
    Static analysis: prevent sorting of the argument
    
    Overrides:
    
    checkArguments in class SystemFunction
    
    Parameters:
    
    visitor - the expression visitor
    
    Throws:
    
    XPathException
  - preEvaluate
```
public Expression preEvaluate(ExpressionVisitor visitor)
```
    preEvaluate: this method suppresses compile-time evaluation by doing nothing
    
    Overrides:
    
    preEvaluate in class FunctionCall
    
    Parameters:
    
    visitor - an expression visitor
    
    Returns:
    
    the result of the early evaluation, or the original expression, or potentially a simplified expression
  - computeSpecialProperties
```
public int computeSpecialProperties()
```
    Get the static properties of this expression (other than its type). The result is bit-signficant. These properties are used for optimizations. In general, if property bit is set, it is true, but if it is unset, the value is unknown.
    
    Overrides:
    
    computeSpecialProperties in class SystemFunction
    
    Returns:
    
    the special properties, as a bit-significant integer
  - addToPathMap
```
public PathMap.PathMapNodeSet addToPathMap(PathMap pathMap,
                                           PathMap.PathMapNodeSet pathMapNodeSet)
```
    Add a representation of a doc() call or similar function to a PathMap. This is a convenience method called by the addToPathMap() methods for doc(), document(), collection() and similar functions. These all create a new root expression in the path map.
    
    Overrides:
    
    addToPathMap in class Expression
    
    Parameters:
    
    pathMap - the PathMap to which the expression should be added
    
    pathMapNodeSet -
    
    Returns:
    
    the pathMapNode representing the focus established by this expression, in the case where this expression is the first operand of a path expression or filter expression
  - iterate
```
public SequenceIterator iterate(XPathContext context)
                         throws XPathException
```
    Evaluate the function to return an iteration of selected nodes.
    
    Specified by:
    
    iterate in interface SequenceIterable
    
    Overrides:
    
    iterate in class Expression
    
    Parameters:
    
    context - supplies the context for evaluation
    
    Returns:
    
    a SequenceIterator that can be used to iterate over the result of the expression
    
    Throws:
    
    XPathException - if any dynamic error occurs evaluating the expression
  - getIdSingle
```
public static SequenceIterator getIdSingle(DocumentInfo doc,
                                           java.lang.String idrefs)
                                    throws XPathException
```
    Get an iterator over the nodes that have an id equal to one of the values is a whitespace separated string
    
    Parameters:
    
    doc - The document to be searched
    
    idrefs - a string containing zero or more whitespace-separated ID values to be found in the document
    
    Returns:
    
    an iterator over the nodes whose ID is one of the specified values
    
    Throws:
    
    XPathException
  - getIdMultiple
```
public static SequenceIterator getIdMultiple(DocumentInfo doc,
                                             SequenceIterator idrefs)
                                      throws XPathException
```
    Get an iterator over the nodes that have an id equal to one of the values is a set of whitespace separated strings
    
    Parameters:
    
    doc - The document to be searched
    
    idrefs - an iterator over a set of strings each of which is a string containing zero or more whitespace-separated ID values to be found in the document
    
    Returns:
    
    an iterator over the nodes whose ID is one of the specified values
    
    Throws:
    
    XPathException

Class Id

Field Summary

Fields inherited from class net.sf.saxon.functions.SystemFunction

Fields inherited from class net.sf.saxon.expr.FunctionCall

Fields inherited from class net.sf.saxon.expr.Expression

Constructor Summary

Method Summary

Methods inherited from class net.sf.saxon.functions.SystemFunction

Methods inherited from class net.sf.saxon.expr.FunctionCall

Methods inherited from class net.sf.saxon.expr.Expression

Methods inherited from class java.lang.Object

Constructor Detail

Id

Method Detail

simplify

checkArguments

preEvaluate

computeSpecialProperties

addToPathMap

iterate

getIdSingle

getIdMultiple