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Entity (Google App Engine API for Java)

java.lang.Object
- com.google.appengine.api.datastore.PropertyContainer
- - com.google.appengine.api.datastore.Entity

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable
```
public final class Entity
extends PropertyContainer
implements java.lang.Cloneable
```
Entity is the fundamental unit of data storage. It has an immutable identifier (contained in the Key) object, a reference to an optional parent Entity, a kind (represented as an arbitrary string), and a set of zero or more typed properties.

See Also:

Serialized Form

Field Summary

Fields
Modifier and Type	Field and Description
`static java.lang.String`	`KEY_RESERVED_PROPERTY` A reserved property name used to refer to the key of the entity.
`static java.lang.String`	`SCATTER_RESERVED_PROPERTY` A reserved property name used to refer to the scatter property of the entity.
`static java.lang.String`	`VERSION_RESERVED_PROPERTY` A reserved property name used to report an entity group's version.

Constructor Summary

Constructors
Constructor and Description
`Entity(Key key)` Create a new `Entity` uniquely identified by the provided `Key`.
`Entity(java.lang.String kind)` Create a new `Entity` with the specified kind and no parent `Entity`.
`Entity(java.lang.String kind, Key parent)` Create a new `Entity` with the specified kind and parent `Entity`.
`Entity(java.lang.String kind, long id)` Create a new `Entity` with the specified kind and ID and no parent `Entity`.
`Entity(java.lang.String kind, long id, Key parent)` Create a new `Entity` with the specified kind and ID and parent `Entity`.
`Entity(java.lang.String kind, java.lang.String keyName)` Create a new `Entity` with the specified kind and key name and no parent `Entity`.
`Entity(java.lang.String kind, java.lang.String keyName, Key parent)` Create a new `Entity` with the specified kind, key name, and parent `Entity`.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`Entity`	`clone()` Returns a shallow copy of this `Entity` instance.
`boolean`	`equals(java.lang.Object object)` Two `Entity` objects are considered equal if they refer to the same entity (i.e.
`java.lang.String`	`getAppId()` Returns the identifier of the application that owns this `Entity`.
`Key`	`getKey()` Returns the `Key` that represents this `Entity`.
`java.lang.String`	`getKind()` Returns a logical type that is associated with this `Entity`.
`java.lang.String`	`getNamespace()` Returns the namespace of the application/namespace that owns this `Entity`.
`Key`	`getParent()` Get a `Key` that corresponds to this the parent `Entity` of this `Entity`.
`int`	`hashCode()`
`void`	`setPropertiesFrom(Entity src)`
`java.lang.String`	`toString()`

Methods inherited from class com.google.appengine.api.datastore.PropertyContainer
getProperties, getProperty, hasProperty, isUnindexedProperty, removeProperty, setIndexedProperty, setPropertiesFrom, setProperty, setUnindexedProperty

Methods inherited from class java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - KEY_RESERVED_PROPERTY
```
public static final java.lang.String KEY_RESERVED_PROPERTY
```
    A reserved property name used to refer to the key of the entity. This string can be used for filtering and sorting by the entity key itself.
    
    See Also:
    
    Constant Field Values
  - SCATTER_RESERVED_PROPERTY
```
public static final java.lang.String SCATTER_RESERVED_PROPERTY
```
    A reserved property name used to refer to the scatter property of the entity. Used for finding split points (e.g. for mapping over a kind).
    
    See Also:
    
    Constant Field Values
  - VERSION_RESERVED_PROPERTY
```
public static final java.lang.String VERSION_RESERVED_PROPERTY
```
    A reserved property name used to report an entity group's version.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - Entity
```
public Entity(java.lang.String kind)
```
    Create a new Entity with the specified kind and no parent Entity. The instantiated Entity will have an incomplete Key when this constructor returns. The Key will remain incomplete until you put the Entity, after which time the Key will have its id set.
  - Entity
```
public Entity(java.lang.String kind,
              Key parent)
```
    Create a new Entity with the specified kind and parent Entity. The instantiated Entity will have an incomplete Key when this constructor returns. The Key will remain incomplete until you put the Entity, after which time the Key will have its id set.
  - Entity
```
public Entity(java.lang.String kind,
              java.lang.String keyName)
```
    Create a new Entity with the specified kind and key name and no parent Entity. The instantiated Entity will have a complete Key when this constructor returns. The Key's name field will be set to the value of keyName.
    This constructor is syntactic sugar for new Entity(KeyFactory.createKey(kind, keyName)).
  - Entity
```
public Entity(java.lang.String kind,
              long id)
```
    Create a new Entity with the specified kind and ID and no parent Entity. The instantiated Entity will have a complete Key when this constructor returns. The Key's id field will be set to the value of id.
    Creating an entity for the purpose of insertion (as opposed to update) with this constructor is discouraged unless the id was obtained from a key returned by a KeyRange obtained from AsyncDatastoreService.allocateIds(String, long) or DatastoreService.allocateIds(String, long) for the same kind.
    This constructor is syntactic sugar for new Entity(KeyFactory.createKey(kind, id)).
  - Entity
```
public Entity(java.lang.String kind,
              java.lang.String keyName,
              Key parent)
```
    Create a new Entity with the specified kind, key name, and parent Entity. The instantiated Entity will have a complete Key when this constructor returns. The Key's name field will be set to the value of keyName.
    This constructor is syntactic sugar for new Entity(KeyFactory.createKey(parent, kind, keyName)).
  - Entity
```
public Entity(java.lang.String kind,
              long id,
              Key parent)
```
    Create a new Entity with the specified kind and ID and parent Entity. The instantiated Entity will have a complete Key when this constructor returns. The Key's id field will be set to the value of id.
    Creating an entity for the purpose of insertion (as opposed to update) with this constructor is discouraged unless the id was obtained from a key returned by a KeyRange obtained from AsyncDatastoreService.allocateIds(Key, String, long) or DatastoreService.allocateIds(Key, String, long) for the same parent and kind.
    This constructor is syntactic sugar for new Entity(KeyFactory.createKey(parent, kind, id)).
  - Entity
```
public Entity(Key key)
```
    Create a new Entity uniquely identified by the provided Key. Creating an entity for the purpose of insertion (as opposed to update) with a key that has its id field set is strongly discouraged unless the key was returned by a KeyRange.
    
    See Also:
    
    KeyRange
- Method Detail
  - equals
```
public boolean equals(java.lang.Object object)
```
    Two Entity objects are considered equal if they refer to the same entity (i.e. their Key objects match).
    
    Overrides:
    
    equals in class java.lang.Object
  - getKey
```
public Key getKey()
```
    Returns the Key that represents this Entity. If the entity has not yet been saved (e.g. via DatastoreService.put), this Key will not be fully specified and cannot be used for certain operations (like DatastoreService.get). Once the Entity has been saved, its Key will be updated to be fully specified.
  - getKind
```
public java.lang.String getKind()
```
    Returns a logical type that is associated with this Entity. This is simply a convenience method that forwards to the Key for this Entity.
  - getParent
```
public Key getParent()
```
    Get a Key that corresponds to this the parent Entity of this Entity. This is simply a convenience method that forwards to the Key for this Entity.
  - hashCode
```
public int hashCode()
```
    Overrides:
    
    hashCode in class java.lang.Object
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - getAppId
```
public java.lang.String getAppId()
```
    Returns the identifier of the application that owns this Entity. This is simply a convenience method that forwards to the Key for this Entity.
  - getNamespace
```
public java.lang.String getNamespace()
```
    Returns the namespace of the application/namespace that owns this Entity. This is simply a convenience method that forwards to the Key for this Entity.
  - clone
```
public Entity clone()
```
    Returns a shallow copy of this Entity instance. Collection properties are cloned as an ArrayList, the type returned from the datastore. Instances of mutable datastore types are cloned as well. Instances of all other types are reused.
    
    Returns:
    
    a shallow copy of this Entity
  - setPropertiesFrom
```
public void setPropertiesFrom(Entity src)
```

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Last updated 2024-02-15 UTC.

Entity (Google App Engine API for Java)

Class Entity

Field Summary

Constructor Summary

Method Summary

Methods inherited from class com.google.appengine.api.datastore.PropertyContainer

Methods inherited from class java.lang.Object

Field Detail

KEY_RESERVED_PROPERTY

SCATTER_RESERVED_PROPERTY

VERSION_RESERVED_PROPERTY

Constructor Detail

Entity

Entity

Entity

Entity

Entity

Entity

Entity

Method Detail

equals

getKey

getKind

getParent

hashCode

toString

getAppId

getNamespace

clone

setPropertiesFrom