org.apache.nutch.crawl
Class MapWritable
java.lang.Object
org.apache.nutch.crawl.MapWritable
- All Implemented Interfaces:
- Writable
public class MapWritable
- extends Object
- implements Writable
A writable map, with a similar behavior as java.util.HashMap
.
In addition to the size of key and value writable tuple two additional bytes
are stored to identify the Writable classes. This means that a maximum of
255 different class types can be used for key and value objects.
A binary-id to class mapping is defined in a static block of this class.
However it is possible to use custom implementations of Writable.
For these custom Writables we write the byte id - utf class name tuple
into the header of each MapWritable that uses these types.
- Author:
- Stefan Groschupf
Field Summary |
static org.apache.commons.logging.Log |
LOG
|
LOG
public static final org.apache.commons.logging.Log LOG
MapWritable
public MapWritable()
MapWritable
public MapWritable(MapWritable map)
- Copy constructor. This constructor makes a deep copy, using serialization /
deserialization to break any possible references to contained objects.
- Parameters:
map
- map to copy from
clear
public void clear()
containsKey
public boolean containsKey(Writable key)
containsValue
public boolean containsValue(Writable value)
get
public Writable get(Writable key)
hashCode
public int hashCode()
- Overrides:
hashCode
in class Object
isEmpty
public boolean isEmpty()
keySet
public Set keySet()
put
public Writable put(Writable key,
Writable value)
putAll
public void putAll(MapWritable map)
remove
public Writable remove(Writable key)
size
public int size()
values
public Collection values()
equals
public boolean equals(Object obj)
- Overrides:
equals
in class Object
toString
public String toString()
- Overrides:
toString
in class Object
write
public void write(DataOutput out)
throws IOException
- Description copied from interface:
Writable
- Writes the fields of this object to
out
.
- Specified by:
write
in interface Writable
- Throws:
IOException
readFields
public void readFields(DataInput in)
throws IOException
- Description copied from interface:
Writable
- Reads the fields of this object from
in
. For efficiency,
implementations should attempt to re-use storage in the existing object
where possible.
- Specified by:
readFields
in interface Writable
- Throws:
IOException
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