org.apache.accumulo.core.iterators
Class SkippingIterator
java.lang.Object
org.apache.accumulo.core.iterators.WrappingIterator
org.apache.accumulo.core.iterators.SkippingIterator
- All Implemented Interfaces:
- SortedKeyValueIterator<Key,Value>
- Direct Known Subclasses:
- ColumnFamilySkippingIterator, DropModIter, FirstEntryInRowIterator, GrepIterator, NoLabelIterator, RegExIterator, TabletStateChangeIterator
public abstract class SkippingIterator
- extends WrappingIterator
Method Summary |
protected abstract void |
consume()
|
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. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
SkippingIterator
public SkippingIterator()
next
public void next()
throws IOException
- Description copied from interface:
SortedKeyValueIterator
- 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.
- Specified by:
next
in interface SortedKeyValueIterator<Key,Value>
- Overrides:
next
in class WrappingIterator
- Throws:
IOException
- if an I/O error occurs.
consume
protected abstract void consume()
throws IOException
- Throws:
IOException
seek
public void seek(Range range,
Collection<ByteSequence> columnFamilies,
boolean inclusive)
throws IOException
- Description copied from interface:
SortedKeyValueIterator
- 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.
Seek may be called multiple times with different parameters after
SortedKeyValueIterator.init(org.apache.accumulo.core.iterators.SortedKeyValueIterator, java.util.Map, org.apache.accumulo.core.iterators.IteratorEnvironment)
is called.
Iterators that examine groups of adjacent key/value pairs (e.g. rows) to determine their top key and value should be sure that they properly handle a seek
to a key in the middle of such a group (e.g. the middle of a row). Even if the client always seeks to a range containing an entire group (a,c), the tablet
server could send back a batch of entries corresponding to (a,b], then reseek the iterator to range (b,c) when the scan is continued.
- Specified by:
seek
in interface SortedKeyValueIterator<Key,Value>
- Overrides:
seek
in class WrappingIterator
- 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.
Copyright © 2012 The Apache Software Foundation. All Rights Reserved.