org.apache.accumulo.core.iterators
Interface SortedKeyValueIterator<K extends org.apache.hadoop.io.WritableComparable<?>,V extends org.apache.hadoop.io.Writable>
- All Known Subinterfaces:
- FileSKVIterator, InterruptibleIterator
- All Known Implementing Classes:
- AgeOffFilter, AggregatingIterator, BloomFilterLayer.Reader, ClientSideIteratorScanner.ScannerTranslator, ColumnAgeOffFilter, ColumnFamilyCounter, ColumnFamilySkippingIterator, ColumnQualifierFilter, Combiner, CountingIterator, DebugIterator, DeletingIterator, DevNull, FamilyIntersectingIterator, FileCFSkippingIterator, Filter, FilteringIterator, FirstEntryInRowIterator, GrepIterator, GrepIterator, HeapIterator, IndexedDocIterator, IntersectingIterator, IntersectingIterator, LargeRowFilter, LargeRowFilter, LongCombiner, MapFileOperations.RangeIterator, MaxCombiner, MinCombiner, MultiIterator, MyMapFile.Reader, NoLabelIterator, OrIterator, RegExFilter, RegExIterator, ReqVisFilter, RFile.Reader, RowDeletingIterator, RowDeletingIterator, RowFilter, SequenceFileIterator, SkippingIterator, SortedKeyIterator, SortedMapIterator, SourceSwitchingIterator, SummingArrayCombiner, SummingCombiner, TimeSettingIterator, TimestampFilter, TypedValueCombiner, VersioningIterator, VersioningIterator, VisibilityFilter, WholeRowIterator, WholeRowIterator, WrappingIterator
public interface SortedKeyValueIterator<K extends org.apache.hadoop.io.WritableComparable<?>,V extends org.apache.hadoop.io.Writable>
An iterator that supports iterating over key and value pairs. Anything implementing this interface should return keys in sorted order.
Method Summary |
SortedKeyValueIterator<K,V> |
deepCopy(IteratorEnvironment env)
Creates a deep copy of this iterator as though seek had not yet been called. |
K |
getTopKey()
Returns top key. |
V |
getTopValue()
Returns top value. |
boolean |
hasTop()
Returns true if the iterator has more elements. |
void |
init(SortedKeyValueIterator<K,V> source,
Map<String,String> options,
IteratorEnvironment env)
Initializes the iterator. |
void |
next()
Advances to the next K,V pair. |
void |
seek(Range range,
Collection<ByteSequence> columnFamilies,
boolean inclusive)
Seeks to the first key in the Range, restricting the resulting K,V pairs to those with the specified columns. |
init
void init(SortedKeyValueIterator<K,V> source,
Map<String,String> options,
IteratorEnvironment env)
throws IOException
- Initializes the iterator. Data should not be read from the source in this method.
- 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:
IOException
- unused.
IllegalArgumentException
- if there are problems with the options.
UnsupportedOperationException
- if not supported.
hasTop
boolean hasTop()
- Returns true if the iterator has more elements.
- Returns:
- true if the iterator has more elements.
- Throws:
IllegalStateException
- if called before seek.
next
void next()
throws IOException
- Advances to the next K,V pair. Note that in minor compaction scope and in non-full major compaction scopes the iterator may see deletion entries. These
entries should be preserved by all iterators except ones that are strictly scan-time iterators that will never be configured for the minc or majc scopes.
Deletion entries are only removed during full major compactions.
- Throws:
IOException
- if an I/O error occurs.
IllegalStateException
- if called before seek.
NoSuchElementException
- if next element doesn't exist.
seek
void seek(Range range,
Collection<ByteSequence> columnFamilies,
boolean inclusive)
throws IOException
- Seeks to the first key in the Range, restricting the resulting K,V pairs to those with the specified columns. An iterator does not have to stop at the end
of the range. The whole range is provided so that iterators can make optimizations.
- 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:
IOException
- if an I/O error occurs.
IllegalArgumentException
- if there are problems with the parameters.
getTopKey
K getTopKey()
- Returns top key. Can be called 0 or more times without affecting behavior of next() or hasTop(). Note that in minor compaction scope and in non-full major
compaction scopes the iterator may see deletion entries. These entries should be preserved by all iterators except ones that are strictly scan-time
iterators that will never be configured for the minc or majc scopes. Deletion entries are only removed during full major compactions.
- Returns:
- K
- Throws:
IllegalStateException
- if called before seek.
NoSuchElementException
- if top element doesn't exist.
getTopValue
V getTopValue()
- Returns top value. Can be called 0 or more times without affecting behavior of next() or hasTop().
- Returns:
- V
- Throws:
IllegalStateException
- if called before seek.
NoSuchElementException
- if top element doesn't exist.
deepCopy
SortedKeyValueIterator<K,V> deepCopy(IteratorEnvironment env)
- 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.
- Parameters:
env
- IteratorEnvironment environment in which iterator is being run.
- Returns:
- SortedKeyValueIterator a copy of this iterator (with the same source and settings).
- Throws:
UnsupportedOperationException
- if not supported.
Copyright © 2012 The Apache Software Foundation. All Rights Reserved.