io.openems.edge.common.channel.value

Class Value<T>

java.lang.Object

io.openems.edge.common.channel.value.Value<T>

Type Parameters:

T - the type of the value

public class Value<T>
extends java.lang.Object

It is important to understand, that a Channel Value could be UNDEFINED (i.e. 'null') at any point in time - e.g. due to lost communication connection to a Device or Service, or because the system is just starting up and does not yet have any data. This class wraps a 'value' information for a Channel and provides convenience methods for retrieving it.

To get the actual value of a Channel using this object, typically one of the following methods will fit:

• get(): gets the value or null. Be aware of NullPointerExceptions!
• getOrError(): gets the value or throws an InvalidValueException if the value is null
• orElse(Object): gets the value; or fallback alternative if the value is null

Field Summary

Fields

Modifier and Type	Field and Description
static java.lang.String	UNDEFINED_VALUE_STRING

Constructor Summary

Constructors

Constructor and Description
Value(Channel<T> parent, T value)

Method Summary

Modifier and Type	Method and Description
<O extends OptionsEnum> O	asEnum() Gets the value as its Enum option.
com.google.gson.JsonElement	asJson() Gets the value in GSON JSON format
java.util.Optional<T>	asOptional() Gets the value as an Optional.
java.lang.String	asOptionString() Gets the value as its String option.
java.lang.String	asString() Gets the value as a formatted String with its unit.
java.lang.String	asStringWithoutUnit() Gets the value as a formatted String without its unit
T	get() Gets the value or null
T	getOrError() Gets the value or throws an Exception on null
java.time.LocalDateTime	getTimestamp() Gets the timestamp when the value was created.
boolean	isDefined() Is the value defined?.
T	orElse(T alternativeValue) Gets the value or the given alternativeValue.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

UNDEFINED_VALUE_STRING

public static final java.lang.String UNDEFINED_VALUE_STRING

See Also:

Constant Field Values

Constructor Detail

Value

public Value(Channel<T> parent,
             T value)

Method Detail

asString

public java.lang.String asString()

Gets the value as a formatted String with its unit. (Same as toString())

Returns:

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

asStringWithoutUnit

public java.lang.String asStringWithoutUnit()

Gets the value as a formatted String without its unit

Returns:

get

public T get()

Gets the value or null

Returns:

getOrError

public T getOrError()
             throws InvalidValueException

Gets the value or throws an Exception on null

Returns:

Throws:

InvalidValueException

asOptional

public java.util.Optional<T> asOptional()

Gets the value as an Optional.

Returns:

isDefined

public boolean isDefined()

Is the value defined?. This is an abbreviation for Value.asOptional().isPresent().

Returns:

true if the value is defined; false if it is UNDEFINED

orElse

public T orElse(T alternativeValue)

Gets the value or the given alternativeValue. This is short for '.asOptional().or()'.

Returns:

asOptionString

public java.lang.String asOptionString()

Gets the value as its String option. Enum options are converted to Strings.

Returns:

Throws:

java.lang.IllegalArgumentException - no matching option existing

asEnum

public <O extends OptionsEnum> O asEnum()

Gets the value as its Enum option.

Returns:

Throws:

java.lang.IllegalArgumentException - no matching Enum option existing

asJson

public com.google.gson.JsonElement asJson()

Gets the value in GSON JSON format

Returns:

getTimestamp

public java.time.LocalDateTime getTimestamp()

Gets the timestamp when the value was created.

Returns:

the timestamp