org.osgi.service.dal

Class FunctionData

java.lang.Object

org.osgi.service.dal.FunctionData

All Implemented Interfaces:

Comparable

Direct Known Subclasses:

AlarmData, BooleanData, KeypadData, LevelData

public abstract class FunctionData
extends Object
implements Comparable

Abstract Function data wrapper. A subclass must be used for an access to the property values by all functions. It takes care about the timestamp and additional metadata. The subclasses are responsible to provide concrete value and unit if required.

Field Summary

Fields

Modifier and Type	Field and Description
static String	DESCRIPTION Metadata key, which value represents the data description.
static String	FIELD_METADATA Represents the metadata field name.
static String	FIELD_TIMESTAMP Represents the timestamp field name.

Constructor Summary

Constructors

Constructor and Description
FunctionData(long timestamp, Map metadata) Constructs new FunctionData instance with the specified arguments.
FunctionData(Map fields) Constructs new FunctionData instance with the specified field values.

Method Summary

Methods

Modifier and Type	Method and Description
int	compareTo(Object o) Compares this FunctionData instance with the given argument.
boolean	equals(Object other) Two FunctionData instances are equal if their metadata and timestamp are equivalent.
Map	getMetadata() Returns FunctionData metadata.
long	getTimestamp() Returns FunctionData timestamp.
int	hashCode() Returns the hash code of this FunctionData.

Methods inherited from class java.lang.Object

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

Field Detail

FIELD_TIMESTAMP

public static final String FIELD_TIMESTAMP

Represents the timestamp field name. The field value is available with getTimestamp(). The field type is long. The constant can be used as a key to FunctionData(Map).

See Also:

Constant Field Values

FIELD_METADATA

public static final String FIELD_METADATA

Represents the metadata field name. The field value is available with getMetadata(). The field type is Map. The constant can be used as a key to FunctionData(Map).

See Also:

Constant Field Values

DESCRIPTION

public static final String DESCRIPTION

Metadata key, which value represents the data description. The property value type is java.lang.String.

See Also:

Constant Field Values

Constructor Detail

FunctionData

public FunctionData(Map fields)

Constructs new FunctionData instance with the specified field values. The map keys must match to the field names. The map values will be assigned to the appropriate class fields. For example, the maps can be: {"timestamp"=Long(1384440775495)}. That map will initialize the FIELD_TIMESTAMP field with 1384440775495. If timestamp is missing, Long.MIN_VALUE is used.

• FIELD_TIMESTAMP - optional field. The value type must be Long.
• FIELD_METADATA - optional field. The value type must be Map.

Parameters:

fields - Contains the new FunctionData instance field values.

Throws:

ClassCastException - If the field value types are not expected.

NullPointerException - If the fields map is null.

FunctionData

public FunctionData(long timestamp,
            Map metadata)

Constructs new FunctionData instance with the specified arguments.

Parameters:

timestamp - The data timestamp optional field.

metadata - The data metadata optional field.

Method Detail

getTimestamp

public long getTimestamp()

Returns FunctionData timestamp. The timestamp is the difference between the value collecting time and midnight, January 1, 1970 UTC. It's measured in milliseconds. The device driver is responsible to generate that value when the value is received from the device. Long.MIN_VALUE value means no timestamp.

Returns:

FunctionData timestamp.

getMetadata

public Map getMetadata()

Returns FunctionData metadata. It's dynamic metadata related only to this specific value. Possible keys:

• DESCRIPTION
• custom key

Returns:

FunctionData metadata or null is there is no metadata.

equals

public boolean equals(Object other)

Two FunctionData instances are equal if their metadata and timestamp are equivalent.

Overrides:

equals in class Object

Parameters:

other - The other instance to compare. It must be of FunctionData type.

Returns:

true if this instance and argument have equivalent metadata and timestamp, false otherwise.

See Also:

Object.equals(java.lang.Object)

hashCode

public int hashCode()

Returns the hash code of this FunctionData.

Overrides:

hashCode in class Object

Returns:

FunctionData hash code.

See Also:

Object.hashCode()

compareTo

public int compareTo(Object o)

Compares this FunctionData instance with the given argument. If the argument is not FunctionData, it throws ClassCastException. Otherwise, this method returns:

• -1 if this instance timestamp is less than the argument timestamp. If they are equivalent, it can be the result of the metadata map deep comparison.
• 0 if all fields are equivalent.
• 1 if this instance timestamp is greater than the argument timestamp. If they are equivalent, it can be the result of the metadata map deep comparison.

Metadata map deep comparison compares the elements of all nested java.util.Map and array instances. null is less than any other non-null instance.

Specified by:

compareTo in interface Comparable

Parameters:

o - FunctionData to be compared.

Returns:

-1, 0 or 1 depending on the comparison rules.

Throws:

ClassCastException - If the method argument is not of type FunctionData or metadata maps contain values of different types for the same key.

NullPointerException - If the method argument is null.

See Also:

Comparable.compareTo(java.lang.Object)