Package com.googlecode.objectify

Class Key<T>

java.lang.Object

com.googlecode.objectify.Key<T>

All Implemented Interfaces:

Serializable, Comparable<Key<?>>

public class Key<T>
extends Object
implements Serializable, Comparable<Key<?>>

A typesafe wrapper for the datastore Key object.

Author:

Jeff Schnitzer , Scott Hernandez

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
protected Key<?>	parent	Cache the instance of the parent wrapper to avoid unnecessary garbage
protected com.google.cloud.datastore.Key	raw

Method Summary

Modifier and Type	Method	Description
int	compareTo(Key<?> other)	The new cloud sdk Key doesn't have compareTo(), so we reimplement the logic from the old GAE SDK.
static <T> Key<T>	create(com.google.cloud.datastore.Key raw)	Create an Objectify key from the native datastore key
static <T> Key<T>	create(Key<?> parent, Class<? extends T> kindClass, long id)	Create an Objectify key from a parent, type, and numeric id
static <T> Key<T>	create(Key<?> parent, Class<? extends T> kindClass, String name)	Create an Objectify key from a parent, type, and string id
static <T> Key<T>	create(Class<? extends T> kindClass, long id)	Create an Objectify key from a type and numeric id
static <T> Key<T>	create(Class<? extends T> kindClass, String name)	Create an Objectify key from a type and string id
static <T> Key<T>	create(String urlSafeString)	Create an Objectify key from a web safe string.
static <T> Key<T>	create(String namespace, Class<? extends T> kindClass, long id)	Create an Objectify key from a namespace, type, and numeric id
static <T> Key<T>	create(String namespace, Class<? extends T> kindClass, String name)	Create an Objectify key from a namespace, type, and string id
static <T> Key<T>	create(T pojo)	Create a key from a registered POJO entity.
boolean	equivalent(Key<T> other)	A type-safe equivalence comparison
boolean	equivalent(Ref<T> other)	A type-safe equivalence comparison
long	getId()
String	getKind()
static String	getKind(Class<?> clazz)	Determines the kind for a Class, as understood by the datastore.
String	getName()
String	getNamespace()
<V> Key<V>	getParent()
com.google.cloud.datastore.Key	getRaw()
<V> Key<V>	getRoot()	Gets the root of a parent graph of keys.
String	getString()	Deprecated. Use toUrlSafe() instead.
static <V> Key<V>	key(com.google.cloud.datastore.Key raw)	Easy null-safe conversion of the raw key.
static com.google.cloud.datastore.Key	key(Key<?> typed)	Easy null-safe conversion of the typed key.
String	toLegacyUrlSafe()	Generates the string that would have been generated by the old appengine SDK.
String	toString()	Creates a human-readable version of this key
String	toUrlSafe()	Call toUrlSafe() on the underlying Key.
String	toWebSafeString()	Deprecated. Use toLegacyUrlSafe(), or if you aren't trying to generate old-style keys, use toUrlSafe().
static <T> Key<T>	valueOf(String webSafeString)	This is an alias for Key.create(String).

Methods inherited from class java.lang.Object

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

Field Detail

raw

protected final com.google.cloud.datastore.Key raw

parent

protected transient Key<?> parent

Cache the instance of the parent wrapper to avoid unnecessary garbage

Method Detail

create

public static <T> Key<T> create(com.google.cloud.datastore.Key raw)

Create an Objectify key from the native datastore key

create

public static <T> Key<T> create(Class<? extends T> kindClass,
                                long id)

Create an Objectify key from a type and numeric id

create

public static <T> Key<T> create(Class<? extends T> kindClass,
                                String name)

Create an Objectify key from a type and string id

create

public static <T> Key<T> create(Key<?> parent,
                                Class<? extends T> kindClass,
                                long id)

Create an Objectify key from a parent, type, and numeric id

create

public static <T> Key<T> create(Key<?> parent,
                                Class<? extends T> kindClass,
                                String name)

Create an Objectify key from a parent, type, and string id

create

public static <T> Key<T> create(String namespace,
                                Class<? extends T> kindClass,
                                long id)

Create an Objectify key from a namespace, type, and numeric id

create

public static <T> Key<T> create(String namespace,
                                Class<? extends T> kindClass,
                                String name)

Create an Objectify key from a namespace, type, and string id

create

public static <T> Key<T> create(String urlSafeString)

Create an Objectify key from a web safe string. Understands both 'modern' and 'legacy' GAE formats.

valueOf

public static <T> Key<T> valueOf(String webSafeString)

This is an alias for Key.create(String). Helps with JAX-RS compliance.

create

public static <T> Key<T> create(T pojo)

Create a key from a registered POJO entity.

getRaw

public com.google.cloud.datastore.Key getRaw()

Returns:

the raw datastore version of this key

getId

public long getId()

Returns:

the id associated with this key, or 0 if this key has a name.

getName

public String getName()

Returns:

the name associated with this key, or null if this key has an id

getKind

public String getKind()

Returns:

the low-level datastore kind associated with this Key

getNamespace

public String getNamespace()

Returns:

the namespace associated with this key

getParent

public <V> Key<V> getParent()

Returns:

the parent key, or null if there is no parent. Note that the parent could potentially have any type.

getRoot

public <V> Key<V> getRoot()

Gets the root of a parent graph of keys. If a Key has no parent, it is the root.

Returns:

the topmost parent key, or this object itself if it is the root. Note that the root key could potentially have any type.

compareTo

public int compareTo(Key<?> other)

The new cloud sdk Key doesn't have compareTo(), so we reimplement the logic from the old GAE SDK.

Specified by:

compareTo in interface Comparable<T>

equivalent

public boolean equivalent(Key<T> other)

A type-safe equivalence comparison

equivalent

public boolean equivalent(Ref<T> other)

A type-safe equivalence comparison

toString

public String toString()

Creates a human-readable version of this key

Overrides:

toString in class Object

getString

@Deprecated
public String getString()

Deprecated.

Use toUrlSafe() instead.

toWebSafeString

@Deprecated
public String toWebSafeString()

Deprecated.

Use toLegacyUrlSafe(), or if you aren't trying to generate old-style keys, use toUrlSafe().

This is an alias for toLegacyUrlSafe() and exists solely for backwards compatibility.

toUrlSafe

public String toUrlSafe()

Call toUrlSafe() on the underlying Key. You can reconstitute a Key<?> using the constructor that takes a string. Note that toString() is only useful for debugging; it cannot be used to create a key with Key.create(String).

toLegacyUrlSafe

public String toLegacyUrlSafe()

Generates the string that would have been generated by the old appengine SDK. The strings look like 'ag1zfnZvb2Rvb2R5bmUwcgcLEgFCGAEM'. The String constructor for Key<?> understands both formats.

key

public static <V> Key<V> key(com.google.cloud.datastore.Key raw)

Easy null-safe conversion of the raw key.

key

public static com.google.cloud.datastore.Key key(Key<?> typed)

Easy null-safe conversion of the typed key.

getKind

public static String getKind(Class<?> clazz)

Determines the kind for a Class, as understood by the datastore. The first class in a hierarchy that has @Entity defines the kind (either explicitly or as that class' simplename).

If no @Entity annotation is found, just uses the simplename as is.