Package org.apache.flink.table.dataview
Class NullSerializer
- java.lang.Object
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- org.apache.flink.api.common.typeutils.TypeSerializer<T>
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- org.apache.flink.api.common.typeutils.base.TypeSerializerSingleton<Object>
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- org.apache.flink.table.dataview.NullSerializer
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- All Implemented Interfaces:
Serializable
@Internal public class NullSerializer extends TypeSerializerSingleton<Object>
A serializer for null.- See Also:
- Serialized Form
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Nested Class Summary
Nested Classes Modifier and Type Class Description static class
NullSerializer.NullSerializerSnapshot
Serializer configuration snapshot for compatibility and format evolution.
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Field Summary
Fields Modifier and Type Field Description static NullSerializer
INSTANCE
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description Object
copy(Object from)
Creates a deep copy of the given element in a new element.Object
copy(Object from, Object reuse)
Creates a copy from the given element.void
copy(DataInputView source, DataOutputView target)
Copies exactly one record from the source input view to the target output view.Object
createInstance()
Creates a new instance of the data type.Object
deserialize(Object reuse, DataInputView source)
De-serializes a record from the given source input view into the given reuse record instance if mutable.Object
deserialize(DataInputView source)
De-serializes a record from the given source input view.int
getLength()
Gets the length of the data type, if it is a fix length data type.boolean
isImmutableType()
Gets whether the type is an immutable type.void
serialize(Object record, DataOutputView target)
Serializes the given record to the given target output view.TypeSerializerSnapshot<Object>
snapshotConfiguration()
Snapshots the configuration of this TypeSerializer.-
Methods inherited from class org.apache.flink.api.common.typeutils.base.TypeSerializerSingleton
duplicate, equals, hashCode
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Field Detail
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INSTANCE
public static final NullSerializer INSTANCE
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Method Detail
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isImmutableType
public boolean isImmutableType()
Description copied from class:TypeSerializer
Gets whether the type is an immutable type.- Specified by:
isImmutableType
in classTypeSerializer<Object>
- Returns:
- True, if the type is immutable.
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createInstance
public Object createInstance()
Description copied from class:TypeSerializer
Creates a new instance of the data type.- Specified by:
createInstance
in classTypeSerializer<Object>
- Returns:
- A new instance of the data type.
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copy
public Object copy(Object from)
Description copied from class:TypeSerializer
Creates a deep copy of the given element in a new element.- Specified by:
copy
in classTypeSerializer<Object>
- Parameters:
from
- The element reuse be copied.- Returns:
- A deep copy of the element.
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copy
public Object copy(Object from, Object reuse)
Description copied from class:TypeSerializer
Creates a copy from the given element. The method makes an attempt to store the copy in the given reuse element, if the type is mutable. This is, however, not guaranteed.- Specified by:
copy
in classTypeSerializer<Object>
- Parameters:
from
- The element to be copied.reuse
- The element to be reused. May or may not be used.- Returns:
- A deep copy of the element.
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getLength
public int getLength()
Description copied from class:TypeSerializer
Gets the length of the data type, if it is a fix length data type.- Specified by:
getLength
in classTypeSerializer<Object>
- Returns:
- The length of the data type, or
-1
for variable length data types.
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serialize
public void serialize(Object record, DataOutputView target) throws IOException
Description copied from class:TypeSerializer
Serializes the given record to the given target output view.- Specified by:
serialize
in classTypeSerializer<Object>
- Parameters:
record
- The record to serialize.target
- The output view to write the serialized data to.- Throws:
IOException
- Thrown, if the serialization encountered an I/O related error. Typically raised by the output view, which may have an underlying I/O channel to which it delegates.
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deserialize
public Object deserialize(DataInputView source) throws IOException
Description copied from class:TypeSerializer
De-serializes a record from the given source input view.- Specified by:
deserialize
in classTypeSerializer<Object>
- Parameters:
source
- The input view from which to read the data.- Returns:
- The deserialized element.
- Throws:
IOException
- Thrown, if the de-serialization encountered an I/O related error. Typically raised by the input view, which may have an underlying I/O channel from which it reads.
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deserialize
public Object deserialize(Object reuse, DataInputView source) throws IOException
Description copied from class:TypeSerializer
De-serializes a record from the given source input view into the given reuse record instance if mutable.- Specified by:
deserialize
in classTypeSerializer<Object>
- Parameters:
reuse
- The record instance into which to de-serialize the data.source
- The input view from which to read the data.- Returns:
- The deserialized element.
- Throws:
IOException
- Thrown, if the de-serialization encountered an I/O related error. Typically raised by the input view, which may have an underlying I/O channel from which it reads.
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copy
public void copy(DataInputView source, DataOutputView target) throws IOException
Description copied from class:TypeSerializer
Copies exactly one record from the source input view to the target output view. Whether this operation works on binary data or partially de-serializes the record to determine its length (such as for records of variable length) is up to the implementer. Binary copies are typically faster. A copy of a record containing two integer numbers (8 bytes total) is most efficiently implemented astarget.write(source, 8);
.- Specified by:
copy
in classTypeSerializer<Object>
- Parameters:
source
- The input view from which to read the record.target
- The target output view to which to write the record.- Throws:
IOException
- Thrown if any of the two views raises an exception.
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snapshotConfiguration
public TypeSerializerSnapshot<Object> snapshotConfiguration()
Description copied from class:TypeSerializer
Snapshots the configuration of this TypeSerializer. This method is only relevant if the serializer is used to state stored in checkpoints/savepoints.The snapshot of the TypeSerializer is supposed to contain all information that affects the serialization format of the serializer. The snapshot serves two purposes: First, to reproduce the serializer when the checkpoint/savepoint is restored, and second, to check whether the serialization format is compatible with the serializer used in the restored program.
IMPORTANT: TypeSerializerSnapshots changed after Flink 1.6. Serializers implemented against Flink versions up to 1.6 should still work, but adjust to new model to enable state evolution and be future-proof. See the class-level comments, section "Upgrading TypeSerializers to the new TypeSerializerSnapshot model" for details.
- Specified by:
snapshotConfiguration
in classTypeSerializer<Object>
- Returns:
- snapshot of the serializer's current configuration (cannot be
null
). - See Also:
TypeSerializerSnapshot.resolveSchemaCompatibility(TypeSerializerSnapshot)
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