net.sf.saxon.functions
Class Concat

java.lang.Object
  extended by net.sf.saxon.expr.Expression
      extended by net.sf.saxon.expr.FunctionCall
          extended by net.sf.saxon.functions.SystemFunction
              extended by net.sf.saxon.functions.Concat
All Implemented Interfaces:
Serializable, SourceLocator, LocationProvider, SaxonLocator, InstructionInfo, Locator

public class Concat
extends SystemFunction

Implementation of the fn:concat() function

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
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
Concat()
           
 
Method Summary
 CharSequence evaluateAsString(XPathContext c)
          Evaluate the function in a string context
 Item evaluateItem(XPathContext c)
          Evaluate in a general context
protected  SequenceType getRequiredType(int arg)
          Get the required type of the nth argument
 void process(XPathContext context)
          Process the instruction in push mode.
 
Methods inherited from class net.sf.saxon.functions.SystemFunction
addContextDocumentArgument, addDocToPathMap, checkArguments, computeCardinality, computeSpecialProperties, copy, equals, getDetails, getErrorCodeForTypeErrors, getImplementationMethod, getItemType, getOperation, makeSystemFunction, optimize, setDetails, useContextItemAsDefault
 
Methods inherited from class net.sf.saxon.expr.FunctionCall
addExternalFunctionCallToPathMap, checkArgumentCount, explain, getArguments, getDisplayName, getExpressionName, getFunctionName, getNumberOfArguments, hashCode, iterateSubExpressions, preEvaluate, promote, replaceSubExpression, setArguments, setFunctionName, simplify, simplifyArguments, toString, typeCheck
 
Methods inherited from class net.sf.saxon.expr.Expression
addToPathMap, adoptChildExpression, checkForUpdatingSubexpressions, checkPermittedContents, computeDependencies, computeStaticProperties, doPromotion, dynamicError, effectiveBooleanValue, evaluatePendingUpdates, explain, getCardinality, getColumnNumber, getColumnNumber, getConstructType, getContainer, getDependencies, getEvaluationMethod, getExecutable, getHostLanguage, getIntegerBounds, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, hasVariableBinding, implementsStaticTypeCheck, isSubtreeExpression, isUpdatingExpression, isVacuousExpression, iterate, iterateEvents, iterateSameFocusSubExpressions, markTailFunctionCalls, resetLocalStaticProperties, setContainer, setEvaluationMethod, setFiltered, setFlattened, setLocationId, staticTypeCheck, suppressValidation, typeError
 
Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait
 

Constructor Detail

Concat

public Concat()
Method Detail

getRequiredType

protected SequenceType getRequiredType(int arg)
Get the required type of the nth argument

Overrides:
getRequiredType in class SystemFunction
Parameters:
arg - the number of the argument whose type is requested, zero-based
Returns:
the required type of the argument as defined in the function signature

evaluateAsString

public CharSequence evaluateAsString(XPathContext c)
                              throws XPathException
Evaluate the function in a string context

Overrides:
evaluateAsString in class Expression
Parameters:
c - The context in which the expression is to be evaluated
Returns:
the value of the expression, evaluated in the current context. The expression must return a string or (); if the value of the expression is (), this method returns "".
Throws:
XPathException - if any dynamic error occurs evaluating the expression

evaluateItem

public Item evaluateItem(XPathContext c)
                  throws XPathException
Evaluate in a general context

Overrides:
evaluateItem in class Expression
Parameters:
c - The context in which the expression is to be evaluated
Returns:
the node or atomic value that results from evaluating the expression; or null to indicate that the result is an empty sequence
Throws:
XPathException - if any dynamic error occurs evaluating the expression

process

public void process(XPathContext context)
             throws XPathException
Process the instruction in push mode. This avoids constructing the concatenated string in memory, instead each argument can be sent straight to the serializer.

Overrides:
process in class Expression
Parameters:
context - The dynamic context, giving access to the current node, the current variables, etc.
Throws:
XPathException - if a dynamic error occurs


Copyright (c) 2004-2011 Saxonica Limited. All rights reserved.