org.apache.pig.piggybank.evaluation.xml

Class XPath

java.lang.Object

org.apache.pig.EvalFunc<String>

org.apache.pig.piggybank.evaluation.xml.XPath

public class XPath
extends EvalFunc<String>

XPath is a function that allows for text extraction from xml

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.pig.EvalFunc

EvalFunc.SchemaType

Field Summary

Fields

Modifier and Type	Field and Description
static String	EMPTY_STRING

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

Constructors

Constructor and Description
XPath()

Method Summary

Methods

Modifier and Type	Method and Description
String	exec(Tuple input) input should contain: 1) xml 2) xpath 3) optional cache xml doc flag 4) optional ignore namespace flag Usage: 1) XPath(xml, xpath) 2) XPath(xml, xpath, false) 3) XPath(xml, xpath, false, false)
List<FuncSpec>	getArgToFuncMapping() Returns argument schemas of the UDF.

Methods inherited from class org.apache.pig.EvalFunc

allowCompileTimeCalculation, finish, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getReturnType, getSchemaName, getSchemaType, getShipFiles, isAsynchronous, needEndOfAllInputProcessing, outputSchema, progress, setEndOfAllInput, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EMPTY_STRING

public static final String EMPTY_STRING

See Also:

Constant Field Values

Constructor Detail

XPath

public XPath()

Method Detail

exec

public String exec(Tuple input)
            throws IOException

input should contain: 1) xml 2) xpath 3) optional cache xml doc flag 4) optional ignore namespace flag Usage: 1) XPath(xml, xpath) 2) XPath(xml, xpath, false) 3) XPath(xml, xpath, false, false)

Specified by:

exec in class EvalFunc<String>

Parameters:

input - 1st element should to be the xml 2nd element should be the xpath 3rd optional boolean cache flag (default true) 4th optional boolean ignore namespace flag (default true) This UDF will cache the last xml document. This is helpful when multiple consecutive xpathAll calls are made for the same xml document. Caching can be turned off to ensure that the UDF's recreates the internal javax.xml.xpath.XPathAll for every call This UDF will also support ignoring the namespace in the xml tags. This will help to search xpath items by ignoring its namespace. Ignoring of the namespace can be turned off for special cases using a fourth argument in the UDF.

Returns:

chararrary result or null if no match

Throws:

IOException

getArgToFuncMapping

public List<FuncSpec> getArgToFuncMapping()
                                   throws FrontendException

Returns argument schemas of the UDF.

Overrides:

getArgToFuncMapping in class EvalFunc<String>

Returns:

List

Throws:

FrontendException