public class FirstEntryInRowIterator extends SkippingIterator implements OptionDescriber
OptionDescriber.IteratorOptions
Constructor and Description |
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FirstEntryInRowIterator() |
FirstEntryInRowIterator(FirstEntryInRowIterator other,
IteratorEnvironment env) |
Modifier and Type | Method and Description |
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protected void |
consume() |
SortedKeyValueIterator<Key,Value> |
deepCopy(IteratorEnvironment env)
Creates a deep copy of this iterator as though seek had not yet been called.
|
OptionDescriber.IteratorOptions |
describeOptions()
Gets an iterator options object that contains information needed to configure this iterator.
|
void |
init(SortedKeyValueIterator<Key,Value> source,
Map<String,String> options,
IteratorEnvironment env)
Initializes the iterator.
|
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.
|
static void |
setNumScansBeforeSeek(IteratorSetting cfg,
int num)
convenience method to set the option to optimize the frequency of scans vs.
|
static void |
setNumScansBeforeSeek(Scanner scanner,
String iteratorName,
int num)
Deprecated.
since 1.4, use
setNumScansBeforeSeek(IteratorSetting, int) |
boolean |
validateOptions(Map<String,String> options)
Check to see if an options map contains all options required by an iterator and that the option values are in the expected formats.
|
next
getSource, getTopKey, getTopValue, hasTop, setSource
public FirstEntryInRowIterator()
public FirstEntryInRowIterator(FirstEntryInRowIterator other, IteratorEnvironment env)
public static void setNumScansBeforeSeek(Scanner scanner, String iteratorName, int num)
setNumScansBeforeSeek(IteratorSetting, int)
scanner
- iteratorName
- num
- public static void setNumScansBeforeSeek(IteratorSetting cfg, int num)
public SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env)
SortedKeyValueIterator
deepCopy
in interface SortedKeyValueIterator<Key,Value>
deepCopy
in class WrappingIterator
env
- IteratorEnvironment environment in which iterator is being run.public void init(SortedKeyValueIterator<Key,Value> source, Map<String,String> options, IteratorEnvironment env) throws IOException
SortedKeyValueIterator
init
in interface SortedKeyValueIterator<Key,Value>
init
in class WrappingIterator
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.IOException
- unused.protected void consume() throws IOException
consume
in class SkippingIterator
IOException
public void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive) throws IOException
SortedKeyValueIterator
SortedKeyValueIterator.init(org.apache.accumulo.core.iterators.SortedKeyValueIterator<K, V>, java.util.Map<java.lang.String, java.lang.String>, 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.seek
in interface SortedKeyValueIterator<Key,Value>
seek
in class SkippingIterator
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.IOException
- if an I/O error occurs.public OptionDescriber.IteratorOptions describeOptions()
OptionDescriber
describeOptions
in interface OptionDescriber
public boolean validateOptions(Map<String,String> options)
OptionDescriber
validateOptions
in interface OptionDescriber
options
- a map of option names to option valuesCopyright © 2012 The Apache Software Foundation. All Rights Reserved.