Class Kryo
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Field Summary
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Constructor Summary
ConstructorsConstructorDescriptionKryo()
Creates a new Kryo with aDefaultClassResolver
and aMapReferenceResolver
.Kryo
(ClassResolver classResolver, ReferenceResolver referenceResolver) Kryo
(ReferenceResolver referenceResolver) Creates a new Kryo with aDefaultClassResolver
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Method Summary
Modifier and TypeMethodDescriptionvoid
addDefaultSerializer
(Class type, Serializer serializer) Instances of the specified class will use the specified serializer.void
addDefaultSerializer
(Class type, Class<? extends Serializer> serializerClass) Instances of the specified class will use the specified serializer.<T> T
copy
(T object) Returns a deep copy of the object.<T> T
copy
(T object, Serializer serializer) Returns a deep copy of the object using the specified serializer.<T> T
copyShallow
(T object) Returns a shallow copy of the object.<T> T
copyShallow
(T object, Serializer serializer) Returns a shallow copy of the object using the specified serializer.Name/value pairs that are available to all serializers.getDefaultSerializer
(Class type) Returns the best matching serializer for a class.int
getDepth()
Returns the number of child objects away from the object graph root.static Class[]
getGenerics
(Type genericType) Returns the first level of classes or interfaces for a generic type.Name/value pairs that are available to all serializers and are cleared after each object graph is serialized or deserialized.int
Returns the lowest, next available integer ID.boolean
getRegistration
(int classID) getRegistration
(Class type) getSerializer
(Class type) Returns the serializer for the registration for the specified class.boolean
Returns true if the specified type is final.boolean
protected Serializer
newDefaultSerializer
(Class type) Called bygetDefaultSerializer(Class)
when no default serializers matched the type.<T> T
newInstance
(Class<T> type) Creates a new instance of a class usingRegistration.getInstantiator()
.protected org.objenesis.instantiator.ObjectInstantiator
newInstantiator
(Class type) Returns a new instantiator for creating new instances of the specified type.newSerializer
(Class<? extends Serializer> serializerClass, Class type) Creates a new instance of the specified serializer for serializing the specified class.Reads a class and returns its registration.readClassAndObject
(Input input) Reads the class and object or null using the registered serializer.<T> T
readObject
(Input input, Class<T> type) Reads an object using the registered serializer.<T> T
readObject
(Input input, Class<T> type, Serializer serializer) Reads an object using the specified serializer.<T> T
readObjectOrNull
(Input input, Class<T> type) Reads an object or null using the registered serializer.<T> T
readObjectOrNull
(Input input, Class<T> type, Serializer serializer) Reads an object or null using the specified serializer.void
Called bySerializer.read(Kryo, Input, Class)
andSerializer.copy(Kryo, Object)
before Kryo can be used to deserialize or copy child objects.register
(Registration registration) Stores the specified registration.Registers the class using the lowest, next available integer ID and thedefault serializer
.Registers the class using the specified ID and thedefault serializer
.register
(Class type, Serializer serializer) Registers the class using the lowest, next available integer ID and the specified serializer.register
(Class type, Serializer serializer, int id) Registers the class using the specified ID and serializer.void
reset()
Resets unregistered class names.void
setAutoReset
(boolean autoReset) If true (the default),reset()
is called automatically after an entire object graph has been read or written.void
setClassLoader
(ClassLoader classLoader) Sets the classloader to resolve unregistered class names to classes.void
setDefaultSerializer
(Class<? extends Serializer> serializer) Sets the serailzer to use when nodefault serializers
match an object's type.void
setInstantiatorStrategy
(org.objenesis.strategy.InstantiatorStrategy strategy) Sets the strategy used bynewInstantiator(Class)
for creating objects.void
setMaxDepth
(int maxDepth) Sets the maxiumum depth of an object graph.void
setReferenceResolver
(ReferenceResolver referenceResolver) Sets the reference resolver and enables references.boolean
setReferences
(boolean references) If true, each appearance of an object in the graph after the first is stored as an integer ordinal.void
setRegistrationRequired
(boolean registrationRequired) If true, an exception is thrown when an unregistered class is encountered.writeClass
(Output output, Class type) Writes a class and returns its registration.void
writeClassAndObject
(Output output, Object object) Writes the class and object or null using the registered serializer.void
writeObject
(Output output, Object object) Writes an object using the registered serializer.void
writeObject
(Output output, Object object, Serializer serializer) Writes an object using the specified serializer.void
writeObjectOrNull
(Output output, Object object, Serializer serializer) Writes an object or null using the specified serializer.void
writeObjectOrNull
(Output output, Object object, Class type) Writes an object or null using the registered serializer for the specified type.
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Field Details
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NULL
public static final byte NULL- See Also:
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NOT_NULL
public static final byte NOT_NULL- See Also:
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Constructor Details
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Kryo
public Kryo()Creates a new Kryo with aDefaultClassResolver
and aMapReferenceResolver
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Kryo
Creates a new Kryo with aDefaultClassResolver
.- Parameters:
referenceResolver
- May be null to disable references.
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Kryo
- Parameters:
referenceResolver
- May be null to disable references.
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Method Details
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setDefaultSerializer
Sets the serailzer to use when nodefault serializers
match an object's type. Default isFieldSerializer
.- See Also:
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addDefaultSerializer
Instances of the specified class will use the specified serializer.- See Also:
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addDefaultSerializer
Instances of the specified class will use the specified serializer. Serializer instances are created as needed vianewSerializer(Class, Class)
. By default, the following classes have a default serializer set:boolean Boolean byte Byte char Character short Short int Integer long Long float Float double Double String byte[] char[] short[] int[] long[] float[] double[] String[] Object[] Map BigInteger BigDecimal KryoSerializable Collection Date Collections.emptyList Collections.singleton Currency StringBuilder Enum Collections.emptyMap Collections.emptySet Calendar StringBuffer Class Collections.singletonList Collections.singletonMap TimeZone TreeMap EnumSet Note that the order default serializers are added is important for a class that may match multiple types. The above default serializers always have a lower priority than subsequent default serializers that are added.
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getDefaultSerializer
Returns the best matching serializer for a class. This method can be overridden to implement custom logic to choose a serializer. -
newDefaultSerializer
Called bygetDefaultSerializer(Class)
when no default serializers matched the type. Subclasses can override this method to customize behavior. The default implementation callsnewSerializer(Class, Class)
using thedefault serializer
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newSerializer
Creates a new instance of the specified serializer for serializing the specified class. Serializers must have a zero argument constructor or one that takes (Kryo), (Class), or (Kryo, Class). -
register
Registers the class using the lowest, next available integer ID and thedefault serializer
. If the class is already registered, the existing entry is updated with the new serializer. Registering a primitive also affects the corresponding primitive wrapper.Because the ID assigned is affected by the IDs registered before it, the order classes are registered is important when using this method. The order must be the same at deserialization as it was for serialization.
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register
Registers the class using the specified ID and thedefault serializer
. If the ID is already in use by the same type, the old entry is overwritten. If the ID is already in use by a different type, aKryoException
is thrown. Registering a primitive also affects the corresponding primitive wrapper.IDs must be the same at deserialization as they were for serialization.
- Parameters:
id
- Must be >= 0. Smaller IDs are serialized more efficiently.
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register
Registers the class using the lowest, next available integer ID and the specified serializer. If the class is already registered, the existing entry is updated with the new serializer. Registering a primitive also affects the corresponding primitive wrapper.Because the ID assigned is affected by the IDs registered before it, the order classes are registered is important when using this method. The order must be the same at deserialization as it was for serialization.
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register
Registers the class using the specified ID and serializer. If the ID is already in use by the same type, the old entry is overwritten. If the ID is already in use by a different type, aKryoException
is thrown. Registering a primitive also affects the corresponding primitive wrapper.IDs must be the same at deserialization as they were for serialization.
- Parameters:
id
- Must be >= 0. Smaller IDs are serialized more efficiently.
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register
Stores the specified registration. If the ID is already in use by the same type, the old entry is overwritten. If the ID is already in use by a different type, aKryoException
is thrown. Registering a primitive also affects the corresponding primitive wrapper.IDs must be the same at deserialization as they were for serialization.
Registration can be suclassed to efficiently store per type information, accessible in serializers via
getRegistration(Class)
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getNextRegistrationId
public int getNextRegistrationId()Returns the lowest, next available integer ID. -
getRegistration
- Throws:
IllegalArgumentException
- if the class is not registered andsetRegistrationRequired(boolean)
is true.- See Also:
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getRegistration
- See Also:
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getSerializer
Returns the serializer for the registration for the specified class. -
writeClass
Writes a class and returns its registration.- Parameters:
type
- May be null.- Returns:
- Will be null if type is null.
- See Also:
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writeObject
Writes an object using the registered serializer. -
writeObject
Writes an object using the specified serializer. The registered serializer is ignored. -
writeObjectOrNull
Writes an object or null using the registered serializer for the specified type.- Parameters:
object
- May be null.
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writeObjectOrNull
Writes an object or null using the specified serializer. The registered serializer is ignored.- Parameters:
object
- May be null.
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writeClassAndObject
Writes the class and object or null using the registered serializer.- Parameters:
object
- May be null.
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readClass
Reads a class and returns its registration.- Returns:
- May be null.
- See Also:
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readObject
Reads an object using the registered serializer. -
readObject
Reads an object using the specified serializer. The registered serializer is ignored. -
readObjectOrNull
Reads an object or null using the registered serializer.- Returns:
- May be null.
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readObjectOrNull
Reads an object or null using the specified serializer. The registered serializer is ignored.- Returns:
- May be null.
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readClassAndObject
Reads the class and object or null using the registered serializer.- Returns:
- May be null.
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reference
Called bySerializer.read(Kryo, Input, Class)
andSerializer.copy(Kryo, Object)
before Kryo can be used to deserialize or copy child objects. Calling this method is unnecessary if Kryo is not used to deserialize or copy child objects.- Parameters:
object
- May be null, unless calling this method fromSerializer.copy(Kryo, Object)
.
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reset
public void reset()Resets unregistered class names. references to previously serialized or deserialized objects. and thegraph context
. Ifauto reset
is true, this method is called automatically when an object graph has been completely serialized or deserialized. If overridden, the super method must be called. -
copy
public <T> T copy(T object) Returns a deep copy of the object. Serializers for the classes involved must supportSerializer.copy(Kryo, Object)
.- Parameters:
object
- May be null.
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copy
Returns a deep copy of the object using the specified serializer. Serializers for the classes involved must supportSerializer.copy(Kryo, Object)
.- Parameters:
object
- May be null.
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copyShallow
public <T> T copyShallow(T object) Returns a shallow copy of the object. Serializers for the classes involved must supportSerializer.copy(Kryo, Object)
.- Parameters:
object
- May be null.
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copyShallow
Returns a shallow copy of the object using the specified serializer. Serializers for the classes involved must supportSerializer.copy(Kryo, Object)
.- Parameters:
object
- May be null.
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getClassResolver
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getReferenceResolver
- Returns:
- May be null.
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setClassLoader
Sets the classloader to resolve unregistered class names to classes. The default is the loader that loaded the Kryo class. -
getClassLoader
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setRegistrationRequired
public void setRegistrationRequired(boolean registrationRequired) If true, an exception is thrown when an unregistered class is encountered. Default is false.If false, when an unregistered class is encountered, its fully qualified class name will be serialized and the
default serializer
for the class used to serialize the object. Subsequent appearances of the class within the same object graph are serialized as an int id.Registered classes are serialized as an int id, avoiding the overhead of serializing the class name, but have the drawback of needing to know the classes to be serialized up front.
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isRegistrationRequired
public boolean isRegistrationRequired() -
setReferences
public boolean setReferences(boolean references) If true, each appearance of an object in the graph after the first is stored as an integer ordinal. When set to true,MapReferenceResolver
is used. This enables references to the same object and cyclic graphs to be serialized, but typically adds overhead of one byte per object. Default is true.- Returns:
- The previous value.
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setReferenceResolver
Sets the reference resolver and enables references. -
getReferences
public boolean getReferences() -
setInstantiatorStrategy
public void setInstantiatorStrategy(org.objenesis.strategy.InstantiatorStrategy strategy) Sets the strategy used bynewInstantiator(Class)
for creating objects. SeeStdInstantiatorStrategy
to create objects via without calling any constructor. SeeSerializingInstantiatorStrategy
to mimic Java's built-in serialization.- Parameters:
strategy
- May be null.
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newInstantiator
Returns a new instantiator for creating new instances of the specified type. By default, an instantiator is returned that uses reflection if the class has a zero argument constructor, an exception is thrown. If astrategy
is set, it will be used instead of throwing an exception. -
newInstance
Creates a new instance of a class usingRegistration.getInstantiator()
. If the registration's instantiator is null, a new one is set usingnewInstantiator(Class)
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getContext
Name/value pairs that are available to all serializers. -
getGraphContext
Name/value pairs that are available to all serializers and are cleared after each object graph is serialized or deserialized. -
getDepth
public int getDepth()Returns the number of child objects away from the object graph root. -
setAutoReset
public void setAutoReset(boolean autoReset) -
setMaxDepth
public void setMaxDepth(int maxDepth) Sets the maxiumum depth of an object graph. This can be used to prevent malicious data from causing a stack overflow. Default isInteger.MAX_VALUE
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isFinal
Returns true if the specified type is final. Final types can be serialized more efficiently because they are non-polymorphic.This can be overridden to force non-final classes to be treated as final. Eg, if an application uses ArrayList extensively but never uses an ArrayList subclass, treating ArrayList as final could allow FieldSerializer to save 1-2 bytes per ArrayList field.
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getGenerics
Returns the first level of classes or interfaces for a generic type.- Returns:
- null if the specified type is not generic or its generic types are not classes.
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