org.apache.oozie.util

Class WritableUtils

java.lang.Object

org.apache.oozie.util.WritableUtils

public class WritableUtils
extends Object

Utility class to write/read Hadoop writables to/from a byte array.

Field Summary

Fields

Modifier and Type	Field and Description
static XLog	LOG

Constructor Summary

Constructors

Constructor and Description
WritableUtils()

Method Summary

Methods

Modifier and Type	Method and Description
static <T extends org.apache.hadoop.io.Writable> T	fromByteArray(byte[] array, Class<T> clazz) Read a writable from a byte array.
static String	readBytesAsString(DataInput dIn)
static <T extends org.apache.hadoop.io.Writable> List<T>	readList(DataInput dataInput, Class<T> clazz) Read list.
static <T extends org.apache.hadoop.io.Writable> Map<String,T>	readMap(DataInput dataInput, Class<T> clazz) Read map.
static <T extends org.apache.hadoop.io.Writable> Map<String,List<T>>	readMapWithList(DataInput dataInput, Class<T> clazz) Read map with list.
static String	readStr(DataInput dataInput) Read a string from a data input supporting null values.
static List<String>	readStringList(DataInput dataInput)
static byte[]	toByteArray(org.apache.hadoop.io.Writable writable) Write a writable to a byte array.
static <T extends org.apache.hadoop.io.Writable> void	writeList(DataOutput dataOutput, List<T> list) Write list.
static <T extends org.apache.hadoop.io.Writable> void	writeMap(DataOutput dataOutput, Map<String,T> map) Write map.
static <T extends org.apache.hadoop.io.Writable> void	writeMapWithList(DataOutput dataOutput, Map<String,List<T>> map) Write map with list.
static void	writeStr(DataOutput dataOutput, String str) Write a string to a data output supporting null values.
static void	writeStringAsBytes(DataOutput dOut, String value)
static void	writeStringList(DataOutput dataOutput, List<String> list)

Methods inherited from class java.lang.Object

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

Field Detail

LOG

public static XLog LOG

Constructor Detail

WritableUtils

public WritableUtils()

Method Detail

toByteArray

public static byte[] toByteArray(org.apache.hadoop.io.Writable writable)

Write a writable to a byte array.

Parameters:

writable - writable to write.

Returns:

array containing the serialized writable.

fromByteArray

public static <T extends org.apache.hadoop.io.Writable> T fromByteArray(byte[] array,
                                                        Class<T> clazz)

Read a writable from a byte array.

Parameters:

array - byte array with the serialized writable.

clazz - writable class.

Returns:

writable deserialized from the byte array.

writeStr

public static void writeStr(DataOutput dataOutput,
            String str)
                     throws IOException

Write a string to a data output supporting null values.

It uses the '||' token to represent null.

Parameters:

dataOutput - data output.

str - string to write.

Throws:

IOException - thrown if the string could not be written.

readStr

public static String readStr(DataInput dataInput)
                      throws IOException

Read a string from a data input supporting null values.

It uses the '||' token to represent null.

Parameters:

dataInput - data input.

Returns:

read string, null if the '||' token was read.

Throws:

IOException - thrown if the string could not be read.

readList

public static <T extends org.apache.hadoop.io.Writable> List<T> readList(DataInput dataInput,
                                                         Class<T> clazz)
                                                              throws IOException

Read list.

Type Parameters:

T - the generic type

Parameters:

dataInput - the data input

clazz - the clazz

Returns:

the list

Throws:

IOException - Signals that an I/O exception has occurred.

readStringList

public static List<String> readStringList(DataInput dataInput)
                                   throws IOException

Throws:

IOException

writeList

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

Write list.

Type Parameters:

T - the generic type

Parameters:

dataOutput - the data output

list - the list

Throws:

IOException - Signals that an I/O exception has occurred.

writeStringList

public static void writeStringList(DataOutput dataOutput,
                   List<String> list)
                            throws IOException

Throws:

IOException

writeMap

public static <T extends org.apache.hadoop.io.Writable> void writeMap(DataOutput dataOutput,
                                                      Map<String,T> map)
                     throws IOException

Write map.

Type Parameters:

T - the generic type

Parameters:

dataOutput - the data output

map - the map

Throws:

IOException - Signals that an I/O exception has occurred.

writeMapWithList

public static <T extends org.apache.hadoop.io.Writable> void writeMapWithList(DataOutput dataOutput,
                                                              Map<String,List<T>> map)
                             throws IOException

Write map with list.

Type Parameters:

T - the generic type

Parameters:

dataOutput - the data output

map - the map

Throws:

IOException - Signals that an I/O exception has occurred.

readMap

public static <T extends org.apache.hadoop.io.Writable> Map<String,T> readMap(DataInput dataInput,
                                                              Class<T> clazz)
                                                                   throws IOException

Read map.

Type Parameters:

T - the generic type

Parameters:

dataInput - the data input

clazz - the clazz

Returns:

the map

Throws:

IOException - Signals that an I/O exception has occurred.

readMapWithList

public static <T extends org.apache.hadoop.io.Writable> Map<String,List<T>> readMapWithList(DataInput dataInput,
                                                                            Class<T> clazz)
                                                                                 throws IOException

Read map with list.

Type Parameters:

T - the generic type

Parameters:

dataInput - the data input

clazz - the clazz

Returns:

the map

Throws:

IOException - Signals that an I/O exception has occurred.

writeStringAsBytes

public static void writeStringAsBytes(DataOutput dOut,
                      String value)
                               throws IOException

Throws:

IOException

readBytesAsString

public static String readBytesAsString(DataInput dIn)
                                throws IOException

Throws:

IOException