FieldValue

public abstract class FieldValue extends Object

Sentinel values that can be used when writing document fields with set() or update().

Public Method Summary

static FieldValue	arrayRemove(Object... elements) Returns a special value that can be used with set() or update() that tells the server to remove the given elements from any array value that already exists on the server.
static FieldValue	arrayUnion(Object... elements) Returns a special value that can be used with set() or update() that tells the server to union the given elements with any array value that already exists on the server.
static FieldValue	delete() Returns a sentinel for use with update() to mark a field for deletion.
static FieldValue	increment(double l) Returns a special value that can be used with set() or update() that tells the server to increment the field's current value by the given value.
static FieldValue	increment(long l) Returns a special value that can be used with set() or update() that tells the server to increment the field's current value by the given value.
static FieldValue	serverTimestamp() Returns a sentinel for use with set() or update() to include a server-generated timestamp in the written data.

Inherited Method Summary

From class java.lang.Object

Object	clone()
boolean	equals(Object arg0)
void	finalize()
final Class<?>	getClass()
int	hashCode()
final void	notify()
final void	notifyAll()
String	toString()
final void	wait(long arg0, int arg1)
final void	wait(long arg0)
final void	wait()

Public Methods

public static FieldValue arrayRemove (Object... elements)

Returns a special value that can be used with set() or update() that tells the server to remove the given elements from any array value that already exists on the server. All instances of each element specified will be removed from the array. If the field being modified is not already an array it will be overwritten with an empty array.

Parameters

elements	The elements to remove from the array.

Returns

• The FieldValue sentinel for use in a call to set() or update().

public static FieldValue arrayUnion (Object... elements)

Returns a special value that can be used with set() or update() that tells the server to union the given elements with any array value that already exists on the server. Each specified element that doesn't already exist in the array will be added to the end. If the field being modified is not already an array it will be overwritten with an array containing exactly the specified elements.

Parameters

elements	The elements to union into the array.

Returns

• The FieldValue sentinel for use in a call to set() or update().

public static FieldValue delete ()

Returns a sentinel for use with update() to mark a field for deletion.

public static FieldValue increment (double l)

Returns a special value that can be used with set() or update() that tells the server to increment the field's current value by the given value.

If the current value is an integer or a double, both the current and the given value will be interpreted as doubles and all arithmetic will follow IEEE 754 semantics. Otherwise, the transformation will set the field to the given value.

Returns

• The FieldValue sentinel for use in a call to set() or update().

public static FieldValue increment (long l)

Returns a special value that can be used with set() or update() that tells the server to increment the field's current value by the given value.

If the current field value is an integer, possible integer overflows are resolved to Long.MAX_VALUE or Long.MIN_VALUE. If the current field value is a double, both values will be interpreted as doubles and the arithmetic will follow IEEE 754 semantics.

If the current field is not an integer or double, or if the field does not yet exist, the transformation will set the field to the given value.

Returns

• The FieldValue sentinel for use in a call to set() or update().

public static FieldValue serverTimestamp ()

Returns a sentinel for use with set() or update() to include a server-generated timestamp in the written data.