org.apache.hadoop.hbase

Class CompoundConfiguration

java.lang.Object

Configuration

org.apache.hadoop.hbase.CompoundConfiguration

@InterfaceAudience.Private
public class CompoundConfiguration
extends Configuration

Do a shallow merge of multiple KV configuration pools. This is a very useful utility class to easily add per-object configurations in addition to wider scope settings. This is different from Configuration.addResource() functionality, which performs a deep merge and mutates the common data structure.

The iterator on CompoundConfiguration is unmodifiable. Obtaining iterator is an expensive operation.

For clarity: the shallow merge allows the user to mutate either of the configuration objects and have changes reflected everywhere. In contrast to a deep merge, that requires you to explicitly know all applicable copies to propagate changes. WARNING: The values set in the CompoundConfiguration are do not handle Property variable substitution. However, if they are set in the underlying configuration substitutions are done.

Field Summary

Fields

Modifier and Type	Field and Description
protected java.util.List<org.apache.hadoop.hbase.CompoundConfiguration.ImmutableConfigMap>	configs

Constructor Summary

Constructors

Constructor and Description
CompoundConfiguration() Default Constructor.

Method Summary

Modifier and Type	Method and Description
CompoundConfiguration	add(Configuration conf) Add Hadoop Configuration object to config list.
CompoundConfiguration	addStringMap(java.util.Map<java.lang.String,java.lang.String> map) Add String map to config list.
CompoundConfiguration	addWritableMap(java.util.Map<ImmutableBytesWritable,ImmutableBytesWritable> map) Add ImmutableBytesWritable map to config list.
void	clear() These methods are unsupported, and no code using CompoundConfiguration depend upon them.
java.lang.String	get(java.lang.String key)
java.lang.String	get(java.lang.String name, java.lang.String defaultValue) Get the value of the name.
java.lang.Class<?>	getClassByName(java.lang.String name)
java.lang.String	getRaw(java.lang.String key)
java.util.Iterator<java.util.Map.Entry<java.lang.String,java.lang.String>>	iterator()
void	set(java.lang.String name, java.lang.String value)
int	size()
java.lang.String	toString()
void	write(java.io.DataOutput out)
void	writeXml(java.io.OutputStream out)

Methods inherited from class java.lang.Object

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

Field Detail

configs

protected java.util.List<org.apache.hadoop.hbase.CompoundConfiguration.ImmutableConfigMap> configs

Constructor Detail

CompoundConfiguration

public CompoundConfiguration()

Default Constructor. Initializes empty configuration

Method Detail

add

public CompoundConfiguration add(Configuration conf)

Add Hadoop Configuration object to config list. The added configuration overrides the previous ones if there are name collisions.

Parameters:

conf - configuration object

Returns:

this, for builder pattern

addWritableMap

public CompoundConfiguration addWritableMap(java.util.Map<ImmutableBytesWritable,ImmutableBytesWritable> map)

Add ImmutableBytesWritable map to config list. This map is generally created by HTableDescriptor or HColumnDescriptor, but can be abstractly used. The added configuration overrides the previous ones if there are name collisions.

Parameters:

map - ImmutableBytesWritable map

Returns:

this, for builder pattern

addStringMap

public CompoundConfiguration addStringMap(java.util.Map<java.lang.String,java.lang.String> map)

Add String map to config list. This map is generally created by HTableDescriptor or HColumnDescriptor, but can be abstractly used. The added configuration overrides the previous ones if there are name collisions.

Returns:

this, for builder pattern

toString

public java.lang.String toString()

get

public java.lang.String get(java.lang.String key)

getRaw

public java.lang.String getRaw(java.lang.String key)

getClassByName

public java.lang.Class<?> getClassByName(java.lang.String name)
                                  throws java.lang.ClassNotFoundException

Throws:

java.lang.ClassNotFoundException

size

public int size()

get

public java.lang.String get(java.lang.String name,
                            java.lang.String defaultValue)

Get the value of the name. If the key is deprecated, it returns the value of the first key which replaces the deprecated key and is not null. If no such property exists, then defaultValue is returned. The CompooundConfiguration does not do property substitution. To do so we need Configuration.getProps to be protected or package visible. Though in hadoop2 it is protected, in hadoop1 the method is private and not accessible. All of the get* methods call this overridden get method.

Parameters:

name - property name.

defaultValue - default value.

Returns:

property value, or defaultValue if the property doesn't exist.

iterator

public java.util.Iterator<java.util.Map.Entry<java.lang.String,java.lang.String>> iterator()

set

public void set(java.lang.String name,
                java.lang.String value)

clear

public void clear()

These methods are unsupported, and no code using CompoundConfiguration depend upon them. Quickly abort upon any attempts to use them.

write

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

Throws:

java.io.IOException

writeXml

public void writeXml(java.io.OutputStream out)
              throws java.io.IOException

Throws:

java.io.IOException