org.apache.cassandra.db

Class AtomDeserializer

java.lang.Object

org.apache.cassandra.db.AtomDeserializer

public class AtomDeserializer
extends java.lang.Object

Helper class to deserialize OnDiskAtom efficiently. More precisely, this class is used by the low-level readers (IndexedSliceReader and SSTableNamesIterator) to ensure we don't do more work than necessary (i.e. we don't allocate/deserialize objects for things we don't care about).

Constructor Summary

Constructors

Constructor and Description
AtomDeserializer(CellNameType type, java.io.DataInput in, ColumnSerializer.Flag flag, int expireBefore, Descriptor.Version version)

Method Summary

Methods

Modifier and Type	Method and Description
int	compareNextTo(Composite composite) Compare the provided composite to the next atom to read on disk.
boolean	hasNext() Whether or not there is more atom to read.
boolean	hasUnprocessed() Whether or not some atom has been read but not processed (neither readNext() nor skipNext() has been called for that atom) yet.
OnDiskAtom	readNext() Returns the next atom.
void	skipNext() Skips the next atom.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

AtomDeserializer

public AtomDeserializer(CellNameType type,
                java.io.DataInput in,
                ColumnSerializer.Flag flag,
                int expireBefore,
                Descriptor.Version version)

Method Detail

hasNext

public boolean hasNext()
                throws java.io.IOException

Whether or not there is more atom to read.

Throws:

java.io.IOException

hasUnprocessed

public boolean hasUnprocessed()
                       throws java.io.IOException

Whether or not some atom has been read but not processed (neither readNext() nor skipNext() has been called for that atom) yet.

Throws:

java.io.IOException

compareNextTo

public int compareNextTo(Composite composite)
                  throws java.io.IOException

Compare the provided composite to the next atom to read on disk. This will not read/deserialize the whole atom but only what is necessary for the comparison. Whenever we know what to do with this atom (read it or skip it), readNext or skipNext should be called.

Throws:

java.io.IOException

readNext

public OnDiskAtom readNext()
                    throws java.io.IOException

Returns the next atom.

Throws:

java.io.IOException

skipNext

public void skipNext()
              throws java.io.IOException

Skips the next atom.

Throws:

java.io.IOException