public abstract class ServerSkippingIterator extends ServerWrappingIterator
SkippingIterator. This class grants protected access to the read only
sourceiterator. For performance reasons, the
sourceiterator is declared final and subclasses directly access it, no longer requiring calls to getSource().
|Constructor and Description|
|Modifier and Type||Method and Description|
Advances to the next K,V pair.
Seeks to the first key in the Range, restricting the resulting K,V pairs to those with the specified columns.
deepCopy, getTopKey, getTopValue, hasTop, init
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public void next() throws IOException
public void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive) throws IOException
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.
columnFamiliesis used, at the lowest level, to determine which data blocks inside of an RFile need to be opened for this iterator. This set of data blocks is also the set of locality groups defined for the given table. If no columnFamilies are provided, the data blocks for all locality groups inside of the correct RFile will be opened and seeked in an attempt to find the correct start key, regardless of the startKey in the
range. In an Accumulo instance in which multiple locality groups exist for a table, it is important to ensure that
columnFamiliesis properly set to the minimum required column families to ensure that data from separate locality groups is not inadvertently read.
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.
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