org.apache.giraph.utils

Class WritableUtils

java.lang.Object

org.apache.giraph.utils.WritableUtils

public class WritableUtils
extends Object

Helper static methods for working with Writable objects.

Method Summary

Modifier and Type	Method and Description
static <T extends org.apache.hadoop.io.Writable> void	copyInto(T from, T to) Copy from into to, by serializing and deserializing it.
static <T extends org.apache.hadoop.io.Writable> void	copyInto(T from, T to, boolean checkOverRead) Copy from into to, by serializing and deserializing it.
static <T extends org.apache.hadoop.io.Writable> T	createCopy(T original) Create a copy of Writable object, by serializing and deserializing it.
static <T extends org.apache.hadoop.io.Writable> T	createCopy(T original, Class<? extends T> outputClass, ImmutableClassesGiraphConfiguration conf) Create a copy of Writable object, by serializing and deserializing it.
static <T extends org.apache.hadoop.io.Writable> T	createCopy(T original, ValueFactory<T> classFactory, ImmutableClassesGiraphConfiguration conf) Create a copy of Writable object, by serializing and deserializing it.
static <T extends org.apache.hadoop.io.Writable> T	createCopy(UnsafeByteArrayOutputStream reusableOut, UnsafeReusableByteArrayInput reusableIn, T original, ImmutableClassesGiraphConfiguration conf) Create a copy of Writable object, by serializing and deserializing it.
static <W extends org.apache.hadoop.io.Writable> W	createWritable(Class<W> klass) Instantiate a new Writable, checking for NullWritable along the way.
static <W extends org.apache.hadoop.io.Writable> W	createWritable(Class<W> klass, ImmutableClassesGiraphConfiguration configuration) Instantiate a new Writable, checking for NullWritable along the way.
static <T extends org.apache.hadoop.io.Writable> void	fromByteArray(byte[] data, T to) Deserialize from given byte array into given writable, using new instance of ExtendedByteArrayDataInput.
static <T extends org.apache.hadoop.io.Writable> void	fromByteArrayUnsafe(byte[] data, T to, UnsafeReusableByteArrayInput reusableInput) Deserialize from given byte array into given writable, using given reusable UnsafeReusableByteArrayInput.
static <T> Class<T>	readClass(DataInput input) Read class from data input.
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> void	readEdge(DataInput in, Edge<I,E> edge) Read an edge from an input stream.
static <T extends Enum<T>> T	readEnum(DataInput input) Reads enum from the stream, serialized by writeEnum
static ExtendedDataOutput	readExtendedDataOutput(DataInput in, ImmutableClassesGiraphConfiguration conf) Read ExtendedDataOutput from DataInput
static void	readFieldsFromByteArray(byte[] byteArray, org.apache.hadoop.io.Writable... writableObjects) Read fields from byteArray to a Writeable object.
static void	readFieldsFromByteArrayWithSize(byte[] byteArray, org.apache.hadoop.io.Writable writableObject, boolean unsafe) Read fields from byteArray to a Writeable object, skipping the size.
static void	readFieldsFromZnode(ZooKeeperExt zkExt, String zkPath, boolean watch, org.apache.zookeeper.data.Stat stat, org.apache.hadoop.io.Writable... writableObjects) Read fields from a ZooKeeper znode.
static <T extends org.apache.hadoop.io.Writable> T	readIfNotNullAndObject(T reusableObject, Class<T> objectClass, DataInput in) First read a boolean saying whether an object is not null, and if it's not read the object
static int[]	readIntArray(DataInput dataInput) Reads primitive int array from input stream.
static List<? extends org.apache.hadoop.io.Writable>	readList(DataInput input) Reads list of Writable objects from data input stream.
static <T extends org.apache.hadoop.io.Writable> List<T>	readListFieldsFromByteArray(byte[] byteArray, Class<? extends T> writableClass, org.apache.hadoop.conf.Configuration conf) Read fields from byteArray to a list of objects.
static <T extends org.apache.hadoop.io.Writable> List<T>	readListFieldsFromZnode(ZooKeeperExt zkExt, String zkPath, boolean watch, org.apache.zookeeper.data.Stat stat, Class<? extends T> writableClass, org.apache.hadoop.conf.Configuration conf) Read fields from a ZooKeeper znode into a list of objects.
static long[]	readLongArray(DataInput dataInput) Reads primitive long array from input stream.
static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> Vertex<I,V,E>	readVertexFromDataInput(DataInput input, ImmutableClassesGiraphConfiguration<I,V,E> conf) Reads data from input stream to initialize Vertex.
static <T extends org.apache.hadoop.io.Writable> T	readWritableObject(DataInput input, ImmutableClassesGiraphConfiguration conf) Reads object from input stream
static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> void	reinitializeVertexFromByteArray(byte[] byteArray, Vertex<I,V,E> vertex, boolean unsafe, ImmutableClassesGiraphConfiguration<I,V,E> conf) Read vertex data from byteArray to a Writeable object, skipping the size.
static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> void	reinitializeVertexFromDataInput(DataInput input, Vertex<I,V,E> vertex, ImmutableClassesGiraphConfiguration<I,V,E> conf) Reads data from input stream to initialize Vertex.
static int	size(org.apache.hadoop.io.Writable w) Serialize given writable object, and return it's size.
static <T extends org.apache.hadoop.io.Writable> byte[]	toByteArray(T w) Serialize given writable to byte array, using new instance of ExtendedByteArrayDataOutput.
static <T extends org.apache.hadoop.io.Writable> byte[]	toByteArrayUnsafe(T w) Serialize given writable to byte array, using new instance of UnsafeByteArrayOutputStream.
static <T> void	writeClass(Class<T> clazz, DataOutput output) Write class to data output.
static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> void	writeEdge(DataOutput out, Edge<I,E> edge) Write an edge to an output stream.
static <T extends Enum<T>> void	writeEnum(T enumValue, DataOutput output) Writes enum into a stream, by serializing class name and it's index
static void	writeExtendedDataOutput(ExtendedDataOutput extendedDataOutput, DataOutput out) Write ExtendedDataOutput to DataOutput
static <T extends org.apache.hadoop.io.Writable> void	writeIfNotNullAndObject(T object, DataOutput out) First write a boolean saying whether an object is not null, and if it's not write the object
static void	writeIntArray(int[] array, DataOutput dataOutput) Writes primitive int array of ints into output stream.
static void	writeList(List<? extends org.apache.hadoop.io.Writable> list, DataOutput output) Writes a list of Writable objects into output stream.
static byte[]	writeListToByteArray(List<? extends org.apache.hadoop.io.Writable> writableList) Write list of object to a byte array.
static ZooKeeperExt.PathStat	writeListToZnode(ZooKeeperExt zkExt, String zkPath, int version, List<? extends org.apache.hadoop.io.Writable> writableList) Write list of objects to a ZooKeeper znode.
static void	writeLongArray(DataOutput dataOutput, long[] array) Writes primitive long array of ints into output stream.
static byte[]	writeToByteArray(org.apache.hadoop.io.Writable... writableObjects) Write object to a byte array.
static byte[]	writeToByteArrayWithSize(org.apache.hadoop.io.Writable writableObject, boolean unsafe) Write object to a byte array with the first 4 bytes as the size of the entire buffer (including the size).
static byte[]	writeToByteArrayWithSize(org.apache.hadoop.io.Writable writableObject, byte[] buffer, boolean unsafe) Write object to a byte array with the first 4 bytes as the size of the entire buffer (including the size).
static ZooKeeperExt.PathStat	writeToZnode(ZooKeeperExt zkExt, String zkPath, int version, org.apache.hadoop.io.Writable... writableObjects) Write object to a ZooKeeper znode.
static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> byte[]	writeVertexToByteArray(Vertex<I,V,E> vertex, boolean unsafe, ImmutableClassesGiraphConfiguration<I,V,E> conf) Write vertex data to byte array with the first 4 bytes as the size of the entire buffer (including the size).
static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> byte[]	writeVertexToByteArray(Vertex<I,V,E> vertex, byte[] buffer, boolean unsafe, ImmutableClassesGiraphConfiguration<I,V,E> conf) Write vertex data to byte array with the first 4 bytes as the size of the entire buffer (including the size).
static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> void	writeVertexToDataOutput(DataOutput output, Vertex<I,V,E> vertex, ImmutableClassesGiraphConfiguration<I,V,E> conf) Writes Vertex data to output stream.
static void	writeWritableObject(org.apache.hadoop.io.Writable object, DataOutput output) Write object to output stream

Methods inherited from class java.lang.Object

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

Method Detail

createWritable

public static <W extends org.apache.hadoop.io.Writable> W createWritable(Class<W> klass)

Instantiate a new Writable, checking for NullWritable along the way.

Type Parameters:

W - type

Parameters:

klass - Class

Returns:

new instance of class

createWritable

public static <W extends org.apache.hadoop.io.Writable> W createWritable(Class<W> klass,
                                                                         ImmutableClassesGiraphConfiguration configuration)

Instantiate a new Writable, checking for NullWritable along the way.

Type Parameters:

W - type

Parameters:

klass - Class

configuration - Configuration

Returns:

new instance of class

readFieldsFromByteArray

public static void readFieldsFromByteArray(byte[] byteArray,
                                           org.apache.hadoop.io.Writable... writableObjects)

Read fields from byteArray to a Writeable object.

Parameters:

byteArray - Byte array to find the fields in.

writableObjects - Objects to fill in the fields.

readFieldsFromZnode

public static void readFieldsFromZnode(ZooKeeperExt zkExt,
                                       String zkPath,
                                       boolean watch,
                                       org.apache.zookeeper.data.Stat stat,
                                       org.apache.hadoop.io.Writable... writableObjects)

Read fields from a ZooKeeper znode.

Parameters:

zkExt - ZooKeeper instance.

zkPath - Path of znode.

watch - Add a watch?

stat - Stat of znode if desired.

writableObjects - Objects to read into.

writeToByteArray

public static byte[] writeToByteArray(org.apache.hadoop.io.Writable... writableObjects)

Write object to a byte array.

Parameters:

writableObjects - Objects to write from.

Returns:

Byte array with serialized object.

readFieldsFromByteArrayWithSize

public static void readFieldsFromByteArrayWithSize(byte[] byteArray,
                                                   org.apache.hadoop.io.Writable writableObject,
                                                   boolean unsafe)

Read fields from byteArray to a Writeable object, skipping the size. Serialization method is choosable

Parameters:

byteArray - Byte array to find the fields in.

writableObject - Object to fill in the fields.

unsafe - Use unsafe deserialization

writeToByteArrayWithSize

public static byte[] writeToByteArrayWithSize(org.apache.hadoop.io.Writable writableObject,
                                              boolean unsafe)

Write object to a byte array with the first 4 bytes as the size of the entire buffer (including the size).

Parameters:

writableObject - Object to write from.

unsafe - Use unsafe serialization?

Returns:

Byte array with serialized object.

writeToByteArrayWithSize

public static byte[] writeToByteArrayWithSize(org.apache.hadoop.io.Writable writableObject,
                                              byte[] buffer,
                                              boolean unsafe)

Write object to a byte array with the first 4 bytes as the size of the entire buffer (including the size).

Parameters:

writableObject - Object to write from.

buffer - Use this buffer instead

unsafe - Use unsafe serialization?

Returns:

Byte array with serialized object.

writeToZnode

public static ZooKeeperExt.PathStat writeToZnode(ZooKeeperExt zkExt,
                                                 String zkPath,
                                                 int version,
                                                 org.apache.hadoop.io.Writable... writableObjects)

Write object to a ZooKeeper znode.

Parameters:

zkExt - ZooKeeper instance.

zkPath - Path of znode.

version - Version of the write.

writableObjects - Objects to write from.

Returns:

Path and stat information of the znode.

writeListToByteArray

public static byte[] writeListToByteArray(List<? extends org.apache.hadoop.io.Writable> writableList)

Write list of object to a byte array.

Parameters:

writableList - List of object to write from.

Returns:

Byte array with serialized objects.

writeListToZnode

public static ZooKeeperExt.PathStat writeListToZnode(ZooKeeperExt zkExt,
                                                     String zkPath,
                                                     int version,
                                                     List<? extends org.apache.hadoop.io.Writable> writableList)

Write list of objects to a ZooKeeper znode.

Parameters:

zkExt - ZooKeeper instance.

zkPath - Path of znode.

version - Version of the write.

writableList - List of objects to write from.

Returns:

Path and stat information of the znode.

readListFieldsFromByteArray

public static <T extends org.apache.hadoop.io.Writable> List<T> readListFieldsFromByteArray(byte[] byteArray,
                                                                                            Class<? extends T> writableClass,
                                                                                            org.apache.hadoop.conf.Configuration conf)

Read fields from byteArray to a list of objects.

Type Parameters:

T - Object type

Parameters:

byteArray - Byte array to find the fields in.

writableClass - Class of the objects to instantiate.

conf - Configuration used for instantiation (i.e Configurable)

Returns:

List of objects.

readListFieldsFromZnode

public static <T extends org.apache.hadoop.io.Writable> List<T> readListFieldsFromZnode(ZooKeeperExt zkExt,
                                                                                        String zkPath,
                                                                                        boolean watch,
                                                                                        org.apache.zookeeper.data.Stat stat,
                                                                                        Class<? extends T> writableClass,
                                                                                        org.apache.hadoop.conf.Configuration conf)

Read fields from a ZooKeeper znode into a list of objects.

Type Parameters:

T - Object type

Parameters:

zkExt - ZooKeeper instance.

zkPath - Path of znode.

watch - Add a watch?

stat - Stat of znode if desired.

writableClass - Class of the objects to instantiate.

conf - Configuration used for instantiation (i.e Configurable)

Returns:

List of objects.

writeExtendedDataOutput

public static void writeExtendedDataOutput(ExtendedDataOutput extendedDataOutput,
                                           DataOutput out)
                                    throws IOException

Write ExtendedDataOutput to DataOutput

Parameters:

extendedDataOutput - ExtendedDataOutput to write

out - DataOutput to write to

Throws:

IOException

readExtendedDataOutput

public static ExtendedDataOutput readExtendedDataOutput(DataInput in,
                                                        ImmutableClassesGiraphConfiguration conf)
                                                 throws IOException

Read ExtendedDataOutput from DataInput

Parameters:

in - DataInput to read from

conf - Configuration

Returns:

ExtendedDataOutput read

Throws:

IOException

writeVertexToByteArray

public static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> byte[] writeVertexToByteArray(Vertex<I,V,E> vertex,
                                                                                                                                                                                byte[] buffer,
                                                                                                                                                                                boolean unsafe,
                                                                                                                                                                                ImmutableClassesGiraphConfiguration<I,V,E> conf)

Write vertex data to byte array with the first 4 bytes as the size of the entire buffer (including the size).

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

Parameters:

vertex - Vertex to write from.

buffer - Use this buffer instead

unsafe - Use unsafe serialization?

conf - Configuration

Returns:

Byte array with serialized object.

writeVertexToByteArray

public static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> byte[] writeVertexToByteArray(Vertex<I,V,E> vertex,
                                                                                                                                                                                boolean unsafe,
                                                                                                                                                                                ImmutableClassesGiraphConfiguration<I,V,E> conf)

Write vertex data to byte array with the first 4 bytes as the size of the entire buffer (including the size).

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

Parameters:

vertex - Vertex to write from.

unsafe - Use unsafe serialization?

conf - Configuration

Returns:

Byte array with serialized object.

reinitializeVertexFromByteArray

public static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> void reinitializeVertexFromByteArray(byte[] byteArray,
                                                                                                                                                                                       Vertex<I,V,E> vertex,
                                                                                                                                                                                       boolean unsafe,
                                                                                                                                                                                       ImmutableClassesGiraphConfiguration<I,V,E> conf)

Read vertex data from byteArray to a Writeable object, skipping the size. Serialization method is choosable. Assumes the vertex has already been initialized and contains values for Id, value, and edges.

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

Parameters:

byteArray - Byte array to find the fields in.

vertex - Vertex to fill in the fields.

unsafe - Use unsafe deserialization

conf - Configuration

writeEdge

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> void writeEdge(DataOutput out,
                                                                                                                         Edge<I,E> edge)
                                                                                                                  throws IOException

Write an edge to an output stream.

Type Parameters:

I - Vertex id

E - Edge value

Parameters:

out - Data output

edge - Edge to write

Throws:

IOException

readEdge

public static <I extends org.apache.hadoop.io.WritableComparable,E extends org.apache.hadoop.io.Writable> void readEdge(DataInput in,
                                                                                                                        Edge<I,E> edge)
                                                                                                                 throws IOException

Read an edge from an input stream.

Type Parameters:

I - Vertex id

E - Edge value

Parameters:

in - Data input

edge - Edge to fill in-place

Throws:

IOException

reinitializeVertexFromDataInput

public static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> void reinitializeVertexFromDataInput(DataInput input,
                                                                                                                                                                                       Vertex<I,V,E> vertex,
                                                                                                                                                                                       ImmutableClassesGiraphConfiguration<I,V,E> conf)
                                                                                                                                                                                throws IOException

Reads data from input stream to initialize Vertex. Assumes the vertex has already been initialized and contains values for Id, value, and edges.

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

Parameters:

input - The input stream

vertex - The vertex to initialize

conf - Configuration

Throws:

IOException

readVertexFromDataInput

public static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> Vertex<I,V,E> readVertexFromDataInput(DataInput input,
                                                                                                                                                                                        ImmutableClassesGiraphConfiguration<I,V,E> conf)
                                                                                                                                                                                 throws IOException

Reads data from input stream to initialize Vertex.

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

Parameters:

input - The input stream

conf - Configuration

Returns:

The vertex

Throws:

IOException

writeVertexToDataOutput

public static <I extends org.apache.hadoop.io.WritableComparable,V extends org.apache.hadoop.io.Writable,E extends org.apache.hadoop.io.Writable> void writeVertexToDataOutput(DataOutput output,
                                                                                                                                                                               Vertex<I,V,E> vertex,
                                                                                                                                                                               ImmutableClassesGiraphConfiguration<I,V,E> conf)
                                                                                                                                                                        throws IOException

Writes Vertex data to output stream.

Type Parameters:

I - Vertex id

V - Vertex value

E - Edge value

Parameters:

output - the output stream

vertex - The vertex to serialize

conf - Configuration

Throws:

IOException

writeClass

public static <T> void writeClass(Class<T> clazz,
                                  DataOutput output)
                           throws IOException

Write class to data output. Also handles the case when class is null.

Type Parameters:

T - Class type

Parameters:

clazz - Class

output - Data output

Throws:

IOException

readClass

public static <T> Class<T> readClass(DataInput input)
                              throws IOException

Read class from data input. Matches writeClass(Class, DataOutput).

Type Parameters:

T - Class type

Parameters:

input - Data input

Returns:

Class, or null if null was written

Throws:

IOException

writeWritableObject

public static void writeWritableObject(org.apache.hadoop.io.Writable object,
                                       DataOutput output)
                                throws IOException

Write object to output stream

Parameters:

object - Object

output - Output stream

Throws:

IOException

readWritableObject

public static <T extends org.apache.hadoop.io.Writable> T readWritableObject(DataInput input,
                                                                             ImmutableClassesGiraphConfiguration conf)
                                                                      throws IOException

Reads object from input stream

Type Parameters:

T - Object type

Parameters:

input - Input stream

conf - Configuration

Returns:

Object

Throws:

IOException

writeList

public static void writeList(List<? extends org.apache.hadoop.io.Writable> list,
                             DataOutput output)
                      throws IOException

Writes a list of Writable objects into output stream. This method is trying to optimize space occupied by class information only storing class object if it is different from the previous one as in most cases arrays tend to have objects of the same type inside.

Parameters:

list - serialized object

output - the output stream

Throws:

IOException

readList

public static List<? extends org.apache.hadoop.io.Writable> readList(DataInput input)
                                                              throws IOException

Reads list of Writable objects from data input stream. Input stream should have class information along with object data.

Parameters:

input - input stream

Returns:

deserialized list

Throws:

IOException

writeIntArray

public static void writeIntArray(int[] array,
                                 DataOutput dataOutput)
                          throws IOException

Writes primitive int array of ints into output stream. Array can be null or empty.

Parameters:

array - array to be written

dataOutput - output stream

Throws:

IOException

readIntArray

public static int[] readIntArray(DataInput dataInput)
                          throws IOException

Reads primitive int array from input stream.

Parameters:

dataInput - input stream to read from

Returns:

may return null or empty array.

Throws:

IOException

writeLongArray

public static void writeLongArray(DataOutput dataOutput,
                                  long[] array)
                           throws IOException

Writes primitive long array of ints into output stream. Array can be null or empty.

Parameters:

array - array to be written

dataOutput - output stream

Throws:

IOException

readLongArray

public static long[] readLongArray(DataInput dataInput)
                            throws IOException

Reads primitive long array from input stream.

Parameters:

dataInput - input stream to read from

Returns:

may return null or empty array.

Throws:

IOException

writeEnum

public static <T extends Enum<T>> void writeEnum(T enumValue,
                                                 DataOutput output)
                                          throws IOException

Writes enum into a stream, by serializing class name and it's index

Type Parameters:

T - Enum type

Parameters:

enumValue - Enum value

output - Output stream

Throws:

IOException

readEnum

public static <T extends Enum<T>> T readEnum(DataInput input)
                                      throws IOException

Reads enum from the stream, serialized by writeEnum

Type Parameters:

T - Enum type

Parameters:

input - Input stream

Returns:

Enum value

Throws:

IOException

copyInto

public static <T extends org.apache.hadoop.io.Writable> void copyInto(T from,
                                                                      T to)

Copy from into to, by serializing and deserializing it. Since it is creating streams inside, it's mostly useful for tests/non-performant code.

Type Parameters:

T - Type of the object

Parameters:

from - Object to copy from

to - Object to copy into

copyInto

public static <T extends org.apache.hadoop.io.Writable> void copyInto(T from,
                                                                      T to,
                                                                      boolean checkOverRead)

Copy from into to, by serializing and deserializing it. Since it is creating streams inside, it's mostly useful for tests/non-performant code.

Type Parameters:

T - Type of the object

Parameters:

from - Object to copy from

to - Object to copy into

checkOverRead - if true, will add one more byte at the end of writing, to make sure read is not touching it. Useful for tests

createCopy

public static <T extends org.apache.hadoop.io.Writable> T createCopy(UnsafeByteArrayOutputStream reusableOut,
                                                                     UnsafeReusableByteArrayInput reusableIn,
                                                                     T original,
                                                                     ImmutableClassesGiraphConfiguration conf)

Create a copy of Writable object, by serializing and deserializing it.

Type Parameters:

T - Type of the object

Parameters:

reusableOut - Reusable output stream to serialize into

reusableIn - Reusable input stream to deserialize out of

original - Original value of which to make a copy

conf - Configuration

Returns:

Copy of the original value

createCopy

public static final <T extends org.apache.hadoop.io.Writable> T createCopy(T original)

Create a copy of Writable object, by serializing and deserializing it.

Type Parameters:

T - Type of the object

Parameters:

original - Original value of which to make a copy

Returns:

Copy of the original value

createCopy

public static final <T extends org.apache.hadoop.io.Writable> T createCopy(T original,
                                                                           Class<? extends T> outputClass,
                                                                           ImmutableClassesGiraphConfiguration conf)

Create a copy of Writable object, by serializing and deserializing it.

Type Parameters:

T - Type of the object

Parameters:

original - Original value of which to make a copy

outputClass - Expected copy class, needs to match original

conf - Configuration

Returns:

Copy of the original value

createCopy

public static final <T extends org.apache.hadoop.io.Writable> T createCopy(T original,
                                                                           ValueFactory<T> classFactory,
                                                                           ImmutableClassesGiraphConfiguration conf)

Create a copy of Writable object, by serializing and deserializing it.

Type Parameters:

T - Type of the object

Parameters:

original - Original value of which to make a copy

classFactory - Factory to create new empty object from

conf - Configuration

Returns:

Copy of the original value

size

public static int size(org.apache.hadoop.io.Writable w)

Serialize given writable object, and return it's size.

Parameters:

w - Writable object

Returns:

it's size after serialization

toByteArray

public static <T extends org.apache.hadoop.io.Writable> byte[] toByteArray(T w)

Serialize given writable to byte array, using new instance of ExtendedByteArrayDataOutput.

Type Parameters:

T - Type of the object

Parameters:

w - Writable object

Returns:

array of bytes

fromByteArray

public static <T extends org.apache.hadoop.io.Writable> void fromByteArray(byte[] data,
                                                                           T to)

Deserialize from given byte array into given writable, using new instance of ExtendedByteArrayDataInput.

Type Parameters:

T - Type of the object

Parameters:

data - Byte array representing writable

to - Object to fill

toByteArrayUnsafe

public static <T extends org.apache.hadoop.io.Writable> byte[] toByteArrayUnsafe(T w)

Serialize given writable to byte array, using new instance of UnsafeByteArrayOutputStream.

Type Parameters:

T - Type of the object

Parameters:

w - Writable object

Returns:

array of bytes

fromByteArrayUnsafe

public static <T extends org.apache.hadoop.io.Writable> void fromByteArrayUnsafe(byte[] data,
                                                                                 T to,
                                                                                 UnsafeReusableByteArrayInput reusableInput)

Deserialize from given byte array into given writable, using given reusable UnsafeReusableByteArrayInput.

Type Parameters:

T - Type of the object

Parameters:

data - Byte array representing writable

to - Object to fill

reusableInput - Reusable input to use

writeIfNotNullAndObject

public static <T extends org.apache.hadoop.io.Writable> void writeIfNotNullAndObject(T object,
                                                                                     DataOutput out)
                                                                              throws IOException

First write a boolean saying whether an object is not null, and if it's not write the object

Type Parameters:

T - Object type

Parameters:

object - Object to write

out - DataOutput to write to

Throws:

IOException

readIfNotNullAndObject

public static <T extends org.apache.hadoop.io.Writable> T readIfNotNullAndObject(T reusableObject,
                                                                                 Class<T> objectClass,
                                                                                 DataInput in)
                                                                          throws IOException

First read a boolean saying whether an object is not null, and if it's not read the object

Type Parameters:

T - Object type

Parameters:

reusableObject - Reuse this object instance

objectClass - Class of the object, to create if reusableObject is null

in - DataInput to read from

Returns:

Object, or null

Throws:

IOException