org.apache.flume

Class Context

java.lang.Object

org.apache.flume.Context

public class Context
extends Object

The context is a key-value store used to pass configuration information throughout the system.

Constructor Summary

Constructors

Constructor and Description
Context()
Context(Map<String,String> paramters)

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Removes all of the mappings from this map.
boolean	containsKey(String key) Returns true if this Context contains a mapping for key.
Boolean	getBoolean(String key) Gets value mapped to key, returning null if unmapped.
Boolean	getBoolean(String key, Boolean defaultValue) Gets value mapped to key, returning defaultValue if unmapped.
Integer	getInteger(String key) Gets value mapped to key, returning null if unmapped.
Integer	getInteger(String key, Integer defaultValue) Gets value mapped to key, returning defaultValue if unmapped.
Long	getLong(String key) Gets value mapped to key, returning null if unmapped.
Long	getLong(String key, Long defaultValue) Gets value mapped to key, returning defaultValue if unmapped.
com.google.common.collect.ImmutableMap<String,String>	getParameters() Gets a copy of the backing map structure.
String	getString(String key) Gets value mapped to key, returning null if unmapped.
String	getString(String key, String defaultValue) Gets value mapped to key, returning defaultValue if unmapped.
com.google.common.collect.ImmutableMap<String,String>	getSubProperties(String prefix) Get properties which start with a prefix.
void	put(String key, String value) Associates the specified value with the specified key in this context.
void	putAll(Map<String,String> map) Associates all of the given map's keys and values in the Context.
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

Context

public Context()

Context

public Context(Map<String,String> paramters)

Method Detail

getParameters

public com.google.common.collect.ImmutableMap<String,String> getParameters()

Gets a copy of the backing map structure.

Returns:

immutable copy of backing map structure

clear

public void clear()

Removes all of the mappings from this map.

getSubProperties

public com.google.common.collect.ImmutableMap<String,String> getSubProperties(String prefix)

Get properties which start with a prefix. When a property is returned, the prefix is removed the from name. For example, if this method is called with a parameter "hdfs." and the context contains: { hdfs.key = value, otherKey = otherValue } this method will return a map containing: { key = value} Note: The prefix must end with a period character. If not this method will raise an IllegalArgumentException.

Parameters:

prefix - key prefix to find and remove from keys in resulting map

Returns:

map with keys which matched prefix with prefix removed from keys in resulting map. If no keys are matched, the returned map is empty

Throws:

IllegalArguemntException - if the given prefix does not end with a period character.

putAll

public void putAll(Map<String,String> map)

Associates all of the given map's keys and values in the Context.

put

public void put(String key,
       String value)

Associates the specified value with the specified key in this context. If the context previously contained a mapping for the key, the old value is replaced by the specified value.

Parameters:

key - key with which the specified value is to be associated

value - to be associated with the specified key

containsKey

public boolean containsKey(String key)

Returns true if this Context contains a mapping for key. Otherwise, returns false.

getBoolean

public Boolean getBoolean(String key,
                 Boolean defaultValue)

Gets value mapped to key, returning defaultValue if unmapped.

Parameters:

key - to be found

defaultValue - returned if key is unmapped

Returns:

value associated with key

getBoolean

public Boolean getBoolean(String key)

Gets value mapped to key, returning null if unmapped.

Note that this method returns an object as opposed to a primitive. The configuration key requested may not be mapped to a value and by returning the primitive object wrapper we can return null. If the key does not exist the return value of this method is assigned directly to a primitive, a NullPointerException will be thrown.

Parameters:

key - to be found

Returns:

value associated with key or null if unmapped

getInteger

public Integer getInteger(String key,
                 Integer defaultValue)

Gets value mapped to key, returning defaultValue if unmapped.

Parameters:

key - to be found

defaultValue - returned if key is unmapped

Returns:

value associated with key

getInteger

public Integer getInteger(String key)

Gets value mapped to key, returning null if unmapped.

Note that this method returns an object as opposed to a primitive. The configuration key requested may not be mapped to a value and by returning the primitive object wrapper we can return null. If the key does not exist the return value of this method is assigned directly to a primitive, a NullPointerException will be thrown.

Parameters:

key - to be found

Returns:

value associated with key or null if unmapped

getLong

public Long getLong(String key,
           Long defaultValue)

Gets value mapped to key, returning defaultValue if unmapped.

Parameters:

key - to be found

defaultValue - returned if key is unmapped

Returns:

value associated with key

getLong

public Long getLong(String key)

Gets value mapped to key, returning null if unmapped.

Note that this method returns an object as opposed to a primitive. The configuration key requested may not be mapped to a value and by returning the primitive object wrapper we can return null. If the key does not exist the return value of this method is assigned directly to a primitive, a NullPointerException will be thrown.

Parameters:

key - to be found

Returns:

value associated with key or null if unmapped

getString

public String getString(String key,
               String defaultValue)

Gets value mapped to key, returning defaultValue if unmapped.

Parameters:

key - to be found

defaultValue - returned if key is unmapped

Returns:

value associated with key

getString

public String getString(String key)

Gets value mapped to key, returning null if unmapped.

Parameters:

key - to be found

Returns:

value associated with key or null if unmapped

toString

public String toString()

Overrides:

toString in class Object