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java.lang.Objectorg.apache.hadoop.hbase.io.HbaseObjectWritable
public class HbaseObjectWritable
This is a customized version of the polymorphic hadoop
ObjectWritable
. It removes UTF8 (HADOOP-414).
Using Text
intead of UTF-8 saves ~2% CPU between reading and writing
objects running a short sequentialWrite Performance Evaluation test just in
ObjectWritable alone; more when we're doing randomRead-ing. Other
optimizations include our passing codes for classes instead of the
actual class names themselves. This makes it so this class needs amendment
if non-Writable classes are introduced -- if passed a Writable for which we
have no code, we just do the old-school passing of the class name, etc. --
but passing codes the savings are large particularly when cell
data is small (If < a couple of kilobytes, the encoding/decoding of class
name and reflection to instantiate class was costing in excess of the cell
handling).
Field Summary | |
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protected static org.apache.commons.logging.Log |
LOG
|
Constructor Summary | |
---|---|
HbaseObjectWritable()
default constructor for writable |
|
HbaseObjectWritable(Class<?> declaredClass,
Object instance)
|
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HbaseObjectWritable(Object instance)
|
Method Summary | |
---|---|
Object |
get()
|
org.apache.hadoop.conf.Configuration |
getConf()
|
Class<?> |
getDeclaredClass()
|
long |
getWritableSize()
Provide a size hint to the caller. |
static long |
getWritableSize(Object instance,
Class declaredClass,
org.apache.hadoop.conf.Configuration conf)
|
void |
readFields(DataInput in)
|
static Object |
readObject(DataInput in,
org.apache.hadoop.conf.Configuration conf)
Read a Writable , String , primitive type, or an array of
the preceding. |
static Object |
readObject(DataInput in,
HbaseObjectWritable objectWritable,
org.apache.hadoop.conf.Configuration conf)
Read a Writable , String , primitive type, or an array of
the preceding. |
void |
set(Object instance)
Reset the instance. |
void |
setConf(org.apache.hadoop.conf.Configuration conf)
|
String |
toString()
|
void |
write(DataOutput out)
|
static void |
writeObject(DataOutput out,
Object instance,
Class declaredClass,
org.apache.hadoop.conf.Configuration conf)
Write a Writable , String , primitive type, or an array of
the preceding. |
Methods inherited from class java.lang.Object |
---|
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait |
Field Detail |
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protected static final org.apache.commons.logging.Log LOG
Constructor Detail |
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public HbaseObjectWritable()
public HbaseObjectWritable(Object instance)
instance
- public HbaseObjectWritable(Class<?> declaredClass, Object instance)
declaredClass
- instance
- Method Detail |
---|
public Object get()
public Class<?> getDeclaredClass()
public void set(Object instance)
instance
- public String toString()
toString
in class Object
Object.toString()
public void readFields(DataInput in) throws IOException
readFields
in interface org.apache.hadoop.io.Writable
IOException
public void write(DataOutput out) throws IOException
write
in interface org.apache.hadoop.io.Writable
IOException
public long getWritableSize()
WritableWithSize
getWritableSize
in interface WritableWithSize
public static long getWritableSize(Object instance, Class declaredClass, org.apache.hadoop.conf.Configuration conf)
public static void writeObject(DataOutput out, Object instance, Class declaredClass, org.apache.hadoop.conf.Configuration conf) throws IOException
Writable
, String
, primitive type, or an array of
the preceding.
out
- instance
- declaredClass
- conf
-
IOException
public static Object readObject(DataInput in, org.apache.hadoop.conf.Configuration conf) throws IOException
Writable
, String
, primitive type, or an array of
the preceding.
in
- conf
-
IOException
public static Object readObject(DataInput in, HbaseObjectWritable objectWritable, org.apache.hadoop.conf.Configuration conf) throws IOException
Writable
, String
, primitive type, or an array of
the preceding.
in
- objectWritable
- conf
-
IOException
public void setConf(org.apache.hadoop.conf.Configuration conf)
setConf
in interface org.apache.hadoop.conf.Configurable
public org.apache.hadoop.conf.Configuration getConf()
getConf
in interface org.apache.hadoop.conf.Configurable
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