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java.lang.Objectorg.apache.accumulo.core.iterators.WrappingIterator
org.apache.accumulo.core.iterators.Filter
public abstract class Filter
A SortedKeyValueIterator that filters entries from its source iterator. Subclasses must implement an accept method: public boolean accept(Key k, Value v); Key/Value pairs for which the accept method returns true are said to match the filter. By default, this class iterates over entries that match its filter. This iterator takes an optional "negate" boolean parameter that defaults to false. If negate is set to true, this class instead omits entries that match its filter, thus iterating over entries that do not match its filter.
| Nested Class Summary |
|---|
| Nested classes/interfaces inherited from interface org.apache.accumulo.core.iterators.OptionDescriber |
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OptionDescriber.IteratorOptions |
| Constructor Summary | |
|---|---|
Filter()
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| Method Summary | |
|---|---|
abstract boolean |
accept(Key k,
Value v)
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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. |
protected void |
findTop()
Iterates over the source until an acceptable key/value pair is found. |
void |
init(SortedKeyValueIterator<Key,Value> 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. |
static void |
setNegate(IteratorSetting is,
boolean negate)
A convenience method for setting the negation option on a filter. |
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. |
| Methods inherited from class org.apache.accumulo.core.iterators.WrappingIterator |
|---|
getSource, getTopKey, getTopValue, hasTop, setSource |
| Methods inherited from class java.lang.Object |
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
| Constructor Detail |
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public Filter()
| Method Detail |
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public SortedKeyValueIterator<Key,Value> deepCopy(IteratorEnvironment env)
SortedKeyValueIterator
deepCopy in interface SortedKeyValueIterator<Key,Value>deepCopy in class WrappingIteratorenv - IteratorEnvironment environment in which iterator is being run.
public void next()
throws IOException
SortedKeyValueIterator
next in interface SortedKeyValueIterator<Key,Value>next in class WrappingIteratorIOException - if an I/O error occurs.
public void seek(Range range,
Collection<ByteSequence> columnFamilies,
boolean inclusive)
throws IOException
SortedKeyValueIterator
seek in interface SortedKeyValueIterator<Key,Value>seek in class WrappingIteratorrange - 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.protected void findTop()
public abstract boolean accept(Key k,
Value v)
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 WrappingIteratorsource - 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.public OptionDescriber.IteratorOptions describeOptions()
OptionDescriber
describeOptions in interface OptionDescriberpublic boolean validateOptions(Map<String,String> options)
OptionDescriber
validateOptions in interface OptionDescriberoptions - a map of option names to option values
public static void setNegate(IteratorSetting is,
boolean negate)
is - IteratorSetting object to configure.negate - if false, filter accepts k/v for which the accept method returns true; if true, filter accepts k/v for which the accept method returns false.
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