- All Implemented Interfaces:
- Direct Known Subclasses:
public abstract class ServerSkippingIterator extends ServerWrappingIteratorAn optimized version of
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().
All Methods Instance Methods Abstract Methods Concrete Methods Modifier and Type Method Description
protected abstract void
next()Advances to the next K,V pair.
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 org.apache.accumulo.core.iterators.ServerWrappingIterator
deepCopy, getTopKey, getTopValue, hasTop, init
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
public void next() throws IOExceptionDescription copied from interface:
SortedKeyValueIteratorAdvances 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.
public void seek(Range range, Collection<ByteSequence> columnFamilies, boolean inclusive) throws IOExceptionDescription copied from interface:
SortedKeyValueIteratorSeeks 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<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.
- Specified by:
Rangeof keys to iterate over.
Collectionof column families to include or exclude.
booleanthat indicates whether to include (true) or exclude (false) column families.
IOException- if an I/O error occurs.