org.apache.accumulo.core.iterators
Class DevNull

java.lang.Object
  org.apache.accumulo.core.iterators.DevNull

All Implemented Interfaces:

SortedKeyValueIterator<Key,Value>

public class DevNull
extends java.lang.Object
implements SortedKeyValueIterator<Key,Value>

An iterator that is useful testing... for example if you want to test ingest performance w/o writing data to disk, insert this iterator for scan as follows using the accumulo shell. config -t ci -s table.iterator.minc.devnull=21,accumulo.core.iterators.DevNull Could also make scans never return anything very quickly by adding it to the scan stack config -t ci -s table.iterator.scan.devnull=21,accumulo.core.iterators.DevNull And to make major compactions never write anything config -t ci -s table.iterator.majc.devnull=21,accumulo.core.iterators.DevNull

Constructor Summary

DevNull()

Method Summary

SortedKeyValueIterator<Key,Value>	deepCopy(IteratorEnvironment env) Creates a deep copy of this iterator as though seek had not yet been called.
Key	getTopKey() Returns top key.
Value	getTopValue() Returns top value.
boolean	hasTop() Returns true if the iterator has more elements.
void	init(SortedKeyValueIterator<Key,Value> source, java.util.Map<java.lang.String,java.lang.String> options, IteratorEnvironment env) Initializes the iterator.
void	next() Advances to the next K,V pair.
void	seek(Range range, java.util.Collection<ByteSequence> columnFamilies, boolean inclusive) An iterator must seek to the first key in the range taking inclusiveness into account.

Methods inherited from class java.lang.Object

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

Constructor Detail

DevNull

public DevNull()

Method Detail

deepCopy

public SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env)

Description copied from interface: SortedKeyValueIterator

Creates a deep copy of this iterator as though seek had not yet been called. init should be called on an iterator before deepCopy is called. init should not need to be called on the copy that is returned by deepCopy; that is, when necessary init should be called in the deepCopy method on the iterator it returns. The behavior is unspecified if init is called after deepCopy either on the original or the copy.

Specified by:

deepCopy in interface SortedKeyValueIterator<Key,Value>

Parameters:

env - IteratorEnvironment environment in which iterator is being run.

Returns:

SortedKeyValueIterator a copy of this iterator (with the same source and settings).

getTopKey

public Key getTopKey()

Description copied from interface: SortedKeyValueIterator

Returns top key. Can be called 0 or more times without affecting behavior of next() or hasTop().

Specified by:

getTopKey in interface SortedKeyValueIterator<Key,Value>

Returns:

K

getTopValue

public Value getTopValue()

Description copied from interface: SortedKeyValueIterator

Returns top value. Can be called 0 or more times without affecting behavior of next() or hasTop().

Specified by:

getTopValue in interface SortedKeyValueIterator<Key,Value>

Returns:

V

hasTop

public boolean hasTop()

Description copied from interface: SortedKeyValueIterator

Returns true if the iterator has more elements.

Specified by:

hasTop in interface SortedKeyValueIterator<Key,Value>

Returns:

true if the iterator has more elements.

init

public void init(SortedKeyValueIterator<Key,Value> source,
                 java.util.Map<java.lang.String,java.lang.String> options,
                 IteratorEnvironment env)
          throws java.io.IOException

Description copied from interface: SortedKeyValueIterator

Initializes the iterator. Data should not be read from the source in this method.

Specified by:

init in interface SortedKeyValueIterator<Key,Value>

Parameters:

source - SortedKeyValueIterator source to read data from.

options - Map map of string option names to option values.

env - IteratorEnvironment environment in which iterator is being run.

Throws:

java.io.IOException - unused.

next

public void next()
          throws java.io.IOException

Description copied from interface: SortedKeyValueIterator

Advances to the next K,V pair.

Specified by:

next in interface SortedKeyValueIterator<Key,Value>

Throws:

java.io.IOException - if an I/O error occurs.

seek

public void seek(Range range,
                 java.util.Collection<ByteSequence> columnFamilies,
                 boolean inclusive)
          throws java.io.IOException

Description copied from interface: SortedKeyValueIterator

An iterator must seek to the first key in the range taking inclusiveness into account. However, an iterator does not have to stop at the end of the range. The whole range is provided so that iterators can make optimizations.

Specified by:

seek in interface SortedKeyValueIterator<Key,Value>

Parameters:

range - Range of keys to iterate over.

columnFamilies - Collection of column families to include or exclude.

inclusive - boolean that indicates whether to include (true) or exclude (false) column families.

Throws:

java.io.IOException - if an I/O error occurs.