org.apache.accumulo.core.iterators
Class AggregatingIterator

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

All Implemented Interfaces:

OptionDescriber, SortedKeyValueIterator<Key,Value>

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

This iterator wraps another iterator. It automatically aggregates.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.accumulo.core.iterators.OptionDescriber

OptionDescriber.IteratorOptions

Constructor Summary

AggregatingIterator()

AggregatingIterator(SortedKeyValueIterator<Key,Value> iterator, ColumnToClassMapping<Aggregator> aggregators)

Method Summary

AggregatingIterator	deepCopy(IteratorEnvironment env) Creates a deep copy of this iterator as though seek had not yet been called.
OptionDescriber.IteratorOptions	describeOptions()
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.
boolean	validateOptions(java.util.Map<java.lang.String,java.lang.String> options)

Methods inherited from class java.lang.Object

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

Constructor Detail

AggregatingIterator

public AggregatingIterator()

AggregatingIterator

public AggregatingIterator(SortedKeyValueIterator<Key,Value> iterator,
                           ColumnToClassMapping<Aggregator> aggregators)
                    throws java.io.IOException

Throws:

java.io.IOException

Method Detail

deepCopy

public AggregatingIterator 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.

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.

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.

describeOptions

public OptionDescriber.IteratorOptions describeOptions()

Specified by:

describeOptions in interface OptionDescriber

validateOptions

public boolean validateOptions(java.util.Map<java.lang.String,java.lang.String> options)

Specified by:

validateOptions in interface OptionDescriber