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com.tangosol.util.extractor
Class DeserializationAccelerator

java.lang.Object
com.tangosol.util.Base
com.tangosol.util.BitHelper
com.tangosol.util.ExternalizableHelper
com.tangosol.util.extractor.AbstractExtractor
com.tangosol.util.extractor.DeserializationAccelerator

All Implemented Interfaces:

ExternalizableLite, PortableObject, QueryMapComparator, IndexAwareExtractor, ValueExtractor, java.io.Serializable, java.util.Comparator

public class DeserializationAccelerator

extends AbstractExtractor

implements IndexAwareExtractor, ExternalizableLite, PortableObject

DeserializationAccelerator is an IndexAwareExtractor implementation that is used to create a ForwardOnlyMapIndex, which in turn is used for deserialization optimization.

Below is an example how to use this feature to optimize deserialization for BinaryEntry.getValue() calls:

   NamedCache cache = ...;
   cache.addIndex(new DeserializationAccelerator(
      IdentityExtractor.INSTANCE), false, null);
 

There are two ways the DeserializationAccelerator could be used: pro-active (default) and on-demand. In the pro-active mode, the underlying ForwardOnlyMapIndex is populated every time the index is rebuilt or updated. In the on-demand mode, the ForwardOnlyMapIndex stores the values only when they are requested.

Since:

Coherence 12.1.3

Author:

gg/hr/jh 2014.03.07

Field Summary

protected ValueExtractor	m_extractor The underlying extractor.
protected boolean	m_fLazy The "lazy" flag.

Fields inherited from class com.tangosol.util.extractor.AbstractExtractor

KEY, m_nTarget, VALUE

Constructor Summary

DeserializationAccelerator()
Construct the DeserializationAccelerator.

DeserializationAccelerator(ValueExtractor extractor)
Construct the DeserializationAccelerator.

DeserializationAccelerator(ValueExtractor extractor, boolean fOnDemand)
Construct the DeserializationAccelerator.

Method Summary

MapIndex	createIndex(boolean fOrdered, java.util.Comparator comparator, java.util.Map mapIndex, BackingMapContext ctx) Create an index and associate it with the corresponding extractor.
MapIndex	destroyIndex(java.util.Map mapIndex) Destroy an existing index and remove it from the given map of indexes.
boolean	equals(java.lang.Object o) Compare the ValueExtractor with another object to determine equality.
java.lang.Object	extract(java.lang.Object oTarget) Using a DeserializationAccelerator to extract values in not supported.
int	hashCode() Determine a hash value for the ValueExtractor object according to the general Object.hashCode() contract.
void	readExternal(java.io.DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object.
void	readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object.
java.lang.String	toString() Return a human-readable description for this DeserializationAccelerator.
void	writeExternal(java.io.DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object.
void	writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Methods inherited from class com.tangosol.util.extractor.AbstractExtractor

compare, compareEntries, extractFromEntry, extractOriginalFromEntry

Methods inherited from class com.tangosol.util.BitHelper

countBits, countBits, countBits, indexOfLSB, indexOfLSB, indexOfLSB, indexOfMSB, indexOfMSB, indexOfMSB, rotateLeft, rotateLeft, rotateLeft, rotateRight, rotateRight, rotateRight, toBitString, toBitString, toBitString, toBytes, toBytes, toBytes, toBytes, toInt, toInt, toLong, toLong

Field Detail

m_extractor

protected ValueExtractor m_extractor

The underlying extractor.

m_fLazy

protected boolean m_fLazy

The "lazy" flag.

Constructor Detail

DeserializationAccelerator

public DeserializationAccelerator()

Construct the DeserializationAccelerator.

DeserializationAccelerator

public DeserializationAccelerator(ValueExtractor extractor)

Construct the DeserializationAccelerator.

Parameters:

extractor - the extractor used by this extractor to create a ForwardOnlyMapIndex; note that the created index will be associated with this extractor in the given index map; passing null is equivalent to using the IdentityExtractor

DeserializationAccelerator

public DeserializationAccelerator(ValueExtractor extractor,
                                  boolean fOnDemand)

Construct the DeserializationAccelerator.

Parameters:

extractor - the extractor used by this extractor to create a ForwardOnlyMapIndex; note that the created index will be associated with this extractor in the given index map; passing null is equivalent to using the IdentityExtractor

fOnDemand - if true, the forward index will be created "on-demand" as the values are attempted to be accessed; otherwise the forward index is populated proactively (default)

Method Detail

createIndex

public MapIndex createIndex(boolean fOrdered,
                            java.util.Comparator comparator,
                            java.util.Map mapIndex,
                            BackingMapContext ctx)

Create an index and associate it with the corresponding extractor. Important note: it is a responsibility of this method's implementations to place the necessary <ValueExtractor, MapIndex> entry into the given map of indexes.

Specified by:

createIndex in interface IndexAwareExtractor

Parameters:

fOrdered - true iff the contents of the indexed information should be ordered; false otherwise

comparator - the Comparator object which imposes an ordering of entries in the index contents; or null if the entries' values natural ordering should be used

mapIndex - Map<ValueExtractor, MapIndex> to be updated with the created index

ctx - The context the index is associate with.

Returns:

the created index; null if the index has not been created

destroyIndex

public MapIndex destroyIndex(java.util.Map mapIndex)

Destroy an existing index and remove it from the given map of indexes.

Specified by:

destroyIndex in interface IndexAwareExtractor

Parameters:

mapIndex - map<ValueExtractor, MapIndex> to be updated by removing the index being destroyed

Returns:

the destroyed index; null if the index does not exist

extract

public java.lang.Object extract(java.lang.Object oTarget)

Using a DeserializationAccelerator to extract values in not supported.

Specified by:

extract in interface ValueExtractor

Overrides:

extract in class AbstractExtractor

Parameters:

oTarget - an Object to retrieve the value from

Returns:

the extracted value as an Object; null is an acceptable value

Throws:

java.lang.UnsupportedOperationException - always

readExternal

public void readExternal(java.io.DataInput in)
                  throws java.io.IOException

Restore the contents of this object by loading the object's state from the passed DataInput object.

Specified by:

readExternal in interface ExternalizableLite

Parameters:

in - the DataInput stream to read data from in order to restore the state of this object

Throws:

java.io.IOException - if an I/O exception occurs

java.io.NotActiveException - if the object is not in its initial state, and therefore cannot be deserialized into

writeExternal

public void writeExternal(java.io.DataOutput out)
                   throws java.io.IOException

Save the contents of this object by storing the object's state into the passed DataOutput object.

Specified by:

writeExternal in interface ExternalizableLite

Parameters:

out - the DataOutput stream to write the state of this object to

Throws:

java.io.IOException - if an I/O exception occurs

readExternal

public void readExternal(PofReader in)
                  throws java.io.IOException

Restore the contents of a user type instance by reading its state using the specified PofReader object.

Specified by:

readExternal in interface PortableObject

Parameters:

in - the PofReader from which to read the object's state

Throws:

java.io.IOException - if an I/O error occurs

writeExternal

public void writeExternal(PofWriter out)
                   throws java.io.IOException

Save the contents of a POF user type instance by writing its state using the specified PofWriter object.

Specified by:

writeExternal in interface PortableObject

Parameters:

out - the PofWriter to which to write the object's state

Throws:

java.io.IOException - if an I/O error occurs

equals

public boolean equals(java.lang.Object o)

Compare the ValueExtractor with another object to determine equality. Two ValueExtractor objects, ve1 and ve2 are considered equal iff ve1.extract(o) equals ve2.extract(o) for all values of o.

Specified by:

equals in interface ValueExtractor

Specified by:

equals in interface java.util.Comparator

Parameters:

o - the reference object with which to compare

Returns:

true iff this ValueExtractor and the passed object are equivalent ValueExtractors

hashCode

public int hashCode()

Determine a hash value for the ValueExtractor object according to the general Object.hashCode() contract.

Specified by:

hashCode in interface ValueExtractor

Returns:

an integer hash value for this ValueExtractor object

toString

public java.lang.String toString()

Return a human-readable description for this DeserializationAccelerator.

Specified by:

toString in interface ValueExtractor

Returns:

a String description of the DeserializationAccelerator

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