uk.ac.starlink.ttools.plot2.config

Class ConfigKey<T>

java.lang.Object

uk.ac.starlink.ttools.plot2.config.ConfigKey<T>

Direct Known Subclasses:

BooleanConfigKey, ChoiceConfigKey, CombinationConfigKey, DoubleArrayConfigKey, DoubleConfigKey, HiddenConfigKey, IntegerConfigKey, OptionConfigKey, StringConfigKey, SubrangeConfigKey, TimeConfigKey, ToggleNullConfigKey

public abstract class ConfigKey<T>
extends Object

Typed key for use in a ConfigMap. As well as serving as a key in ConfigMap, this class has methods to allow a command-line or graphical interface to be constructed for the corresponding values automatically.

Note that this class does not sport the Equality annotation. A ConfigKey is normally considered equal only to itself, not to other similarly-named ConfigKeys.

Since:

22 Feb 2013

Author:

Mark Taylor

Constructor Summary

Constructors

Constructor and Description
ConfigKey(ConfigMeta meta, Class<T> clazz, T dflt) Constructor.

Method Summary

Modifier and Type	Method and Description
T	cast(Object value) Converts an object to the value type of this key.
abstract Specifier<T>	createSpecifier() Constructs a graphical control with which the user can specify a suitable value for association with this key.
T	getDefaultValue() Returns the default value associated with this key.
ConfigMeta	getMeta() Returns metadata about this key.
Class<T>	getValueClass() Returns the type of value described by this key.
abstract T	stringToValue(String txt) Decodes a string value to the value type of this key.
String	toString()
abstract String	valueToString(T value) Reports a value as a string.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConfigKey

public ConfigKey(ConfigMeta meta,
                 Class<T> clazz,
                 T dflt)

Constructor.

Parameters:

meta - metadata describing this key

clazz - value type for the values indexed by this key

dflt - default value when key not present in map

Method Detail

getMeta

public ConfigMeta getMeta()

Returns metadata about this key.

Returns:

metadata

getValueClass

public Class<T> getValueClass()

Returns the type of value described by this key.

Returns:

class

getDefaultValue

public T getDefaultValue()

Returns the default value associated with this key. This value may be used when no value is explicitly supplied for this key.

Returns:

default value

cast

public T cast(Object value)

Converts an object to the value type of this key.

Parameters:

value - untyped value

Returns:

typed value

stringToValue

public abstract T stringToValue(String txt)
                         throws ConfigException

Decodes a string value to the value type of this key. An empty string should be interpreted as a null value, but this may cause an exception if null is not a permissible value for this key.

Parameters:

txt - string representation of value

Returns:

value

Throws:

ConfigException

valueToString

public abstract String valueToString(T value)

Reports a value as a string. If at all possible the roundtripping should be possible, so stringToValue(valueToString(v)).equals(v). A null value, if permitted, should be represented as an empty string.

Parameters:

value - possible value associated with this key

Returns:

string representation

createSpecifier

public abstract Specifier<T> createSpecifier()

Constructs a graphical control with which the user can specify a suitable value for association with this key.

Returns:

new specifier

toString

public String toString()

Overrides:

toString in class Object