## net.sf.saxon.functions
Class Concat

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

All Implemented Interfaces:
  Serializable, SourceLocator, LocationProvider, SaxonLocator, EvaluableItem, SequenceIterable, InstructionInfo, Locator

    public class Concat

extends SystemFunction

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, EVENT_FEED_METHOD, ITEM_FEED_METHOD, ITERATE_METHOD, locationId, PROCESS_METHOD, PUSH_SELECTION, staticProperties, 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, getDetails, getErrorCodeForTypeErrors, getImplementationMethod, getItemType, makeSystemFunction, optimize, setDetails, useContextItemAsDefault`

Methods inherited from class net.sf.saxon.expr.FunctionCall
`addExternalFunctionCallToPathMap, checkArgumentCount, equals, 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, getIntrinsicDependencies, getLineNumber, getLineNumber, getLocationId, getLocationProvider, getObjectName, getProperties, getProperty, getPublicId, getSlotsUsed, getSpecialProperties, getSystemId, getSystemId, hasLoopingSubexpression, 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

  Specified by:
    `evaluateItem` in interface `EvaluableItem`
  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`

Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.