org.apache.pig.builtin
Class AVG
java.lang.Object
org.apache.pig.EvalFunc<DataAtom>
org.apache.pig.builtin.AVG
- All Implemented Interfaces:
- Algebraic
public class AVG
- extends EvalFunc<DataAtom>
- implements Algebraic
Generates the average of the values of the first field of a tuple. This class is Algebraic in
implemenation, so if possible the execution will be split into a local and global application
Constructor Summary |
AVG()
|
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
AVG
public AVG()
exec
public void exec(Tuple input,
DataAtom output)
throws IOException
- Description copied from class:
EvalFunc
- This callback method must be implemented by all subclasses. This
is the method that will be invoked on every Tuple of a given dataset.
Since the dataset may be divided up in a variety of ways the programmer
should not make assumptions about state that is maintained between
invocations of this method.
- Specified by:
exec
in class EvalFunc<DataAtom>
- Parameters:
input
- the Tuple to be processed.
- Throws:
IOException
getInitial
public String getInitial()
- Specified by:
getInitial
in interface Algebraic
- Returns:
- A string to instatiate f_init. f_init should be an eval func
getIntermed
public String getIntermed()
- Specified by:
getIntermed
in interface Algebraic
- Returns:
- A string to instantiate f_intermed. f_intermed should be an eval func
getFinal
public String getFinal()
- Specified by:
getFinal
in interface Algebraic
- Returns:
- A string to instantiate f_final. f_final should be an eval func parametrized by
the same datum as the eval func implementing this interface
combine
protected static void combine(DataBag values,
Tuple output)
throws IOException
- Throws:
IOException
count
protected static long count(Tuple input)
throws IOException
- Throws:
IOException
sum
protected static double sum(Tuple input)
throws IOException
- Throws:
IOException
outputSchema
public Schema outputSchema(Schema input)
- Overrides:
outputSchema
in class EvalFunc<DataAtom>
- Parameters:
input
- Schema of the input
- Returns:
- Schema of the output
Copyright © ${year} The Apache Software Foundation