org.apache.kafka.common.config
Class ConfigDef

java.lang.Object
  org.apache.kafka.common.config.ConfigDef

public class ConfigDef
extends java.lang.Object

This class is used for specifying the set of expected configurations, their type, their defaults, their documentation, and any special validation logic used for checking the correctness of the values the user provides.

Usage of this class looks something like this:

 ConfigDef defs = new ConfigDef();
 defs.define("config_name", Type.STRING, "default string value", "This configuration is used for blah blah blah.");
 defs.define("another_config_name", Type.INT, 42, Range.atLeast(0), "More documentation on this config");
 
 Properties props = new Properties();
 props.setProperty("config_name", "some value");
 Map<String, Object> configs = defs.parse(props);
 
 String someConfig = (String) configs.get("config_name"); // will return "some value"
 int anotherConfig = (Integer) configs.get("another_config_name"); // will return default value of 42
 

This class can be used stand-alone or in combination with AbstractConfig which provides some additional functionality for accessing configs.

Nested Class Summary

static class	ConfigDef.Importance
static class	ConfigDef.Range Validation logic for numeric ranges
static class	ConfigDef.Type The config types
static interface	ConfigDef.Validator Validation logic the user may provide
static class	ConfigDef.ValidString

Constructor Summary

ConfigDef()

Method Summary

ConfigDef	define(java.lang.String name, ConfigDef.Type type, ConfigDef.Importance importance, java.lang.String documentation) Define a required parameter with no default value and no special validation logic
ConfigDef	define(java.lang.String name, ConfigDef.Type type, ConfigDef.Validator validator, ConfigDef.Importance importance, java.lang.String documentation) Define a required parameter with no default value
ConfigDef	define(java.lang.String name, ConfigDef.Type type, java.lang.Object defaultValue, ConfigDef.Importance importance, java.lang.String documentation) Define a new configuration with no special validation logic
ConfigDef	define(java.lang.String name, ConfigDef.Type type, java.lang.Object defaultValue, ConfigDef.Validator validator, ConfigDef.Importance importance, java.lang.String documentation) Define a new configuration
java.util.Map<java.lang.String,java.lang.Object>	parse(java.util.Map<?,?> props) Parse and validate configs against this configuration definition.
java.lang.String	toHtmlTable()

Methods inherited from class java.lang.Object

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

Constructor Detail

ConfigDef

public ConfigDef()

Method Detail

define

public ConfigDef define(java.lang.String name,
                        ConfigDef.Type type,
                        java.lang.Object defaultValue,
                        ConfigDef.Validator validator,
                        ConfigDef.Importance importance,
                        java.lang.String documentation)

Define a new configuration

Parameters:

name - The name of the config parameter

type - The type of the config

defaultValue - The default value to use if this config isn't present

validator - A validator to use in checking the correctness of the config

importance - The importance of this config: is this something you will likely need to change.

documentation - The documentation string for the config

Returns:

This ConfigDef so you can chain calls

define

public ConfigDef define(java.lang.String name,
                        ConfigDef.Type type,
                        java.lang.Object defaultValue,
                        ConfigDef.Importance importance,
                        java.lang.String documentation)

Define a new configuration with no special validation logic

Parameters:

name - The name of the config parameter

type - The type of the config

defaultValue - The default value to use if this config isn't present

importance - The importance of this config: is this something you will likely need to change.

documentation - The documentation string for the config

Returns:

This ConfigDef so you can chain calls

define

public ConfigDef define(java.lang.String name,
                        ConfigDef.Type type,
                        ConfigDef.Validator validator,
                        ConfigDef.Importance importance,
                        java.lang.String documentation)

Define a required parameter with no default value

Parameters:

name - The name of the config parameter

type - The type of the config

validator - A validator to use in checking the correctness of the config

importance - The importance of this config: is this something you will likely need to change.

documentation - The documentation string for the config

Returns:

This ConfigDef so you can chain calls

define

public ConfigDef define(java.lang.String name,
                        ConfigDef.Type type,
                        ConfigDef.Importance importance,
                        java.lang.String documentation)

Define a required parameter with no default value and no special validation logic

Parameters:

name - The name of the config parameter

type - The type of the config

importance - The importance of this config: is this something you will likely need to change.

documentation - The documentation string for the config

Returns:

This ConfigDef so you can chain calls

parse

public java.util.Map<java.lang.String,java.lang.Object> parse(java.util.Map<?,?> props)

Parse and validate configs against this configuration definition. The input is a map of configs. It is expected that the keys of the map are strings, but the values can either be strings or they may already be of the appropriate type (int, string, etc). This will work equally well with either java.util.Properties instances or a programmatically constructed map.

Parameters:

props - The configs to parse and validate

Returns:

Parsed and validated configs. The key will be the config name and the value will be the value parsed into the appropriate type (int, string, etc)

toHtmlTable

public java.lang.String toHtmlTable()