Serializer

Documentation of 'org.mapdb.Serializer' Java class Serializer

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java.lang.Object
- org.mapdb.Serializer<A>

Direct Known Subclasses:

Serializer.Array, Serializer.CompressionDeflateWrapper, Serializer.CompressionWrapper, SerializerBase
```
public abstract class Serializer<A>
extends java.lang.Object
```
Provides serialization and deserialization

Nested Class Summary

Nested Classes
Modifier and Type	Class and Description
`static class`	`Serializer.Array<T>`
`static class`	`Serializer.CompressionDeflateWrapper<E>` wraps another serializer and (de)compresses its output/input using Deflate
`static class`	`Serializer.CompressionWrapper<E>` wraps another serializer and (de)compresses its output/input

Field Summary

Fields
Modifier and Type	Field and Description
`static Serializer<java.lang.Object>`	`BASIC` Basic serializer for most classes in `java.lang` and `java.util` packages.
`static Serializer<java.math.BigDecimal>`	`BIG_DECIMAL`
`static Serializer<java.math.BigInteger>`	`BIG_INTEGER`
`static Serializer<java.lang.Boolean>`	`BOOLEAN`
`static Serializer<boolean[]>`	`BOOLEAN_ARRAY`
`static Serializer<java.lang.Byte>`	`BYTE`
`static Serializer<byte[]>`	`BYTE_ARRAY` Serializes `byte[]` it adds header which contains size information
`static Serializer<byte[]>`	`BYTE_ARRAY_NOSIZE` Serializes `byte[]` directly into underlying store It does not store size, so it can not be used in Maps and other collections.
`static Serializer<java.lang.Character>`	`CHAR`
`static Serializer<char[]>`	`CHAR_ARRAY` Serializes `char[]` it adds header which contains size information
`static Serializer<java.lang.Class<?>>`	`CLASS`
`static Serializer<java.util.Date>`	`DATE`
`static Serializer<java.lang.Double>`	`DOUBLE`
`static Serializer<double[]>`	`DOUBLE_ARRAY` Serializes `double[]` it adds header which contains size information
`static Serializer<java.lang.Float>`	`FLOAT`
`static Serializer<float[]>`	`FLOAT_ARRAY`
`static Serializer<java.lang.Object>`	`ILLEGAL_ACCESS` Always throws `IllegalAccessError` when invoked.
`static Serializer<int[]>`	`INT_ARRAY` Serializes `int[]` it adds header which contains size information
`static Serializer<java.lang.Integer>`	`INTEGER` Serializes Integer into 4 bytes, used mainly for testing.
`static Serializer<java.lang.Integer>`	`INTEGER_PACKED` Packs positive Integer, so smaller positive values occupy less than 4 bytes.
`static Serializer<java.lang.Integer>`	`INTEGER_PACKED_ZIGZAG` packs Integer so small values occupy less than 4 bytes.
`static Serializer<java.lang.Object>`	`JAVA` Serializer which uses standard Java Serialization with `ObjectInputStream` and `ObjectOutputStream`
`static Serializer<java.lang.Long>`	`LONG` Serializes Long into 8 bytes, used mainly for testing.
`static Serializer<long[]>`	`LONG_ARRAY` Serializes `long[]` it adds header which contains size information
`static Serializer<java.lang.Long>`	`LONG_PACKED` Packs positive LONG, so smaller positive values occupy less than 8 bytes.
`static Serializer<java.lang.Long>`	`LONG_PACKED_ZIGZAG` packs Long so small values occupy less than 8 bytes.
`static Serializer<java.lang.Long>`	`RECID` Packs recid + it adds 3bits checksum.
`static Serializer<long[]>`	`RECID_ARRAY`
`static Serializer<java.lang.Short>`	`SHORT`
`static Serializer<short[]>`	`SHORT_ARRAY`
`static Serializer<java.lang.String>`	`STRING` Serializes strings using UTF8 encoding.
`static Serializer<java.lang.String>`	`STRING_ASCII` Serializes strings using ASCII encoding (8 bit character).
`static Serializer<java.lang.String>`	`STRING_INTERN` Serializes strings using UTF8 encoding.
`static Serializer<java.lang.String>`	`STRING_NOSIZE` Serializes strings using UTF8 encoding.
`static Serializer<java.lang.String>`	`STRING_XXHASH` Serializes strings using UTF8 encoding.
`static Serializer<java.util.UUID>`	`UUID` Serializers `UUID` class

Constructor Summary

Constructors
Constructor and Description

Serializer()

Constructors
Constructor and Description
`Serializer()`

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract A`	`deserialize(java.io.DataInput in, int available)` Deserialize the content of an object from a DataInput.
`boolean`	`equals(A a1, A a2)`
`int`	`fixedSize()` Data could be serialized into record with variable size or fixed size.
`BTreeKeySerializer`	`getBTreeKeySerializer(java.util.Comparator comparator)`
`int`	`hashCode(A a, int seed)`
`boolean`	`isTrusted()` MapDB has relax record size boundary checking.
`abstract void`	`serialize(java.io.DataOutput out, A value)` Serialize the content of an object into a ObjectOutput
`java.lang.Object`	`valueArrayCopyOfRange(java.lang.Object vals, int from, int to)`
`java.lang.Object`	`valueArrayDeleteValue(java.lang.Object vals, int pos)`
`java.lang.Object`	`valueArrayDeserialize(java.io.DataInput in, int size)`
`java.lang.Object`	`valueArrayEmpty()`
`java.lang.Object`	`valueArrayFromArray(java.lang.Object[] objects)`
`A`	`valueArrayGet(java.lang.Object vals, int pos)`
`java.lang.Object`	`valueArrayPut(java.lang.Object vals, int pos, A newValue)`
`void`	`valueArraySerialize(java.io.DataOutput out, java.lang.Object vals)`
`int`	`valueArraySize(java.lang.Object vals)`
`java.lang.Object`	`valueArrayUpdateVal(java.lang.Object vals, int pos, A newValue)`

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

- Field Detail
  - CHAR
```
public static final Serializer<java.lang.Character> CHAR
```
  - STRING_XXHASH
```
public static final Serializer<java.lang.String> STRING_XXHASH
```
    Serializes strings using UTF8 encoding. Stores string size so can be used as collection serializer. Does not handle null values
    Unlike STRING this method hashes String with more reliable XXHash.
  - STRING
```
public static final Serializer<java.lang.String> STRING
```
    Serializes strings using UTF8 encoding. Stores string size so can be used as collection serializer. Does not handle null values
  - STRING_INTERN
```
public static final Serializer<java.lang.String> STRING_INTERN
```
    Serializes strings using UTF8 encoding. Deserialized String is interned String.intern(), so it could save some memory. Stores string size so can be used as collection serializer. Does not handle null values
  - STRING_ASCII
```
public static final Serializer<java.lang.String> STRING_ASCII
```
    Serializes strings using ASCII encoding (8 bit character). Is faster compared to UTF8 encoding. Stores string size so can be used as collection serializer. Does not handle null values
  - STRING_NOSIZE
```
public static final Serializer<java.lang.String> STRING_NOSIZE
```
    Serializes strings using UTF8 encoding. Used mainly for testing. Does not handle null values.
  - LONG
```
public static final Serializer<java.lang.Long> LONG
```
    Serializes Long into 8 bytes, used mainly for testing. Does not handle null values.
  - LONG_PACKED
```
public static final Serializer<java.lang.Long> LONG_PACKED
```
    Packs positive LONG, so smaller positive values occupy less than 8 bytes. Large and negative values could occupy 8 or 9 bytes.
  - LONG_PACKED_ZIGZAG
```
public static final Serializer<java.lang.Long> LONG_PACKED_ZIGZAG
```
    packs Long so small values occupy less than 8 bytes. Large (positive and negative) values could occupy more 8 to 9 bytes. It uses zigzag conversion before packing, number is multiplied by two, with last bite indicating negativity.
  - INTEGER
```
public static final Serializer<java.lang.Integer> INTEGER
```
    Serializes Integer into 4 bytes, used mainly for testing. Does not handle null values.
  - INTEGER_PACKED
```
public static final Serializer<java.lang.Integer> INTEGER_PACKED
```
    Packs positive Integer, so smaller positive values occupy less than 4 bytes. Large and negative values could occupy 4 or 5 bytes.
  - INTEGER_PACKED_ZIGZAG
```
public static final Serializer<java.lang.Integer> INTEGER_PACKED_ZIGZAG
```
    packs Integer so small values occupy less than 4 bytes. Large (positive and negative) values could occupy more 4 to 5 bytes. It uses zigzag conversion before packing, number is multiplied by two, with last bite indicating negativity.
  - BOOLEAN
```
public static final Serializer<java.lang.Boolean> BOOLEAN
```
  - RECID
```
public static final Serializer<java.lang.Long> RECID
```
    Packs recid + it adds 3bits checksum.
  - RECID_ARRAY
```
public static final Serializer<long[]> RECID_ARRAY
```
  - ILLEGAL_ACCESS
```
public static final Serializer<java.lang.Object> ILLEGAL_ACCESS
```
    Always throws IllegalAccessError when invoked. Useful for testing and assertions.
  - BYTE_ARRAY
```
public static final Serializer<byte[]> BYTE_ARRAY
```
    Serializes byte[] it adds header which contains size information
  - BYTE_ARRAY_NOSIZE
```
public static final Serializer<byte[]> BYTE_ARRAY_NOSIZE
```
    Serializes byte[] directly into underlying store It does not store size, so it can not be used in Maps and other collections.
  - CHAR_ARRAY
```
public static final Serializer<char[]> CHAR_ARRAY
```
    Serializes char[] it adds header which contains size information
  - INT_ARRAY
```
public static final Serializer<int[]> INT_ARRAY
```
    Serializes int[] it adds header which contains size information
  - LONG_ARRAY
```
public static final Serializer<long[]> LONG_ARRAY
```
    Serializes long[] it adds header which contains size information
  - DOUBLE_ARRAY
```
public static final Serializer<double[]> DOUBLE_ARRAY
```
    Serializes double[] it adds header which contains size information
  - JAVA
```
public static final Serializer<java.lang.Object> JAVA
```
    Serializer which uses standard Java Serialization with ObjectInputStream and ObjectOutputStream
  - UUID
```
public static final Serializer<java.util.UUID> UUID
```
    Serializers UUID class
  - BYTE
```
public static final Serializer<java.lang.Byte> BYTE
```
  - FLOAT
```
public static final Serializer<java.lang.Float> FLOAT
```
  - DOUBLE
```
public static final Serializer<java.lang.Double> DOUBLE
```
  - SHORT
```
public static final Serializer<java.lang.Short> SHORT
```
  - BOOLEAN_ARRAY
```
public static final Serializer<boolean[]> BOOLEAN_ARRAY
```
  - SHORT_ARRAY
```
public static final Serializer<short[]> SHORT_ARRAY
```
  - FLOAT_ARRAY
```
public static final Serializer<float[]> FLOAT_ARRAY
```
  - BIG_INTEGER
```
public static final Serializer<java.math.BigInteger> BIG_INTEGER
```
  - BIG_DECIMAL
```
public static final Serializer<java.math.BigDecimal> BIG_DECIMAL
```
  - CLASS
```
public static final Serializer<java.lang.Class<?>> CLASS
```
  - DATE
```
public static final Serializer<java.util.Date> DATE
```
  - BASIC
```
public static final Serializer<java.lang.Object> BASIC
```
    Basic serializer for most classes in java.lang and java.util packages. It does not handle custom POJO classes. It also does not handle classes which require access to DB itself.
- Constructor Detail
  - Serializer
```
public Serializer()
```
- Method Detail
  - serialize
```
public abstract void serialize(java.io.DataOutput out,
                               A value)
                        throws java.io.IOException
```
    Serialize the content of an object into a ObjectOutput
    
    Parameters:
    
    out - ObjectOutput to save object into
    
    value - Object to serialize
    
    Throws:
    
    java.io.IOException - in case of IO error
  - deserialize
```
public abstract A deserialize(java.io.DataInput in,
                              int available)
                       throws java.io.IOException
```
    Deserialize the content of an object from a DataInput.
    
    Parameters:
    
    in - to read serialized data from
    
    available - how many bytes are available in DataInput for reading, may be -1 (in streams) or 0 (null).
    
    Returns:
    
    deserialized object
    
    Throws:
    
    java.io.IOException - in case of IO error
  - fixedSize
```
public int fixedSize()
```
    Data could be serialized into record with variable size or fixed size. Some optimizations can be applied to serializers with fixed size
    
    Returns:
    
    fixed size or -1 for variable size
  - isTrusted
```
public boolean isTrusted()
```
    MapDB has relax record size boundary checking. It expect deserializer to read exactly as many bytes as were writen during serialization. If deserializer reads more bytes it might start reading others record data in store.
    Some serializers (Kryo) have problems with this. To prevent this we can not read data directly from store, but must copy them into separate byte[]. So zero copy optimalizations is disabled by default, and must be explicitly enabled here.
    This flag indicates if this serializer was 'verified' to read as many bytes as it writes. It should be also much better tested etc.
    
    Returns:
    
    true if this serializer is well tested and writes as many bytes as it reads.
  - equals
```
public boolean equals(A a1,
                      A a2)
```
  - hashCode
```
public int hashCode(A a,
                    int seed)
```
  - valueArraySerialize
```
public void valueArraySerialize(java.io.DataOutput out,
                                java.lang.Object vals)
                         throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - valueArrayDeserialize
```
public java.lang.Object valueArrayDeserialize(java.io.DataInput in,
                                              int size)
                                       throws java.io.IOException
```
    Throws:
    
    java.io.IOException
  - valueArrayGet
```
public A valueArrayGet(java.lang.Object vals,
                       int pos)
```
  - valueArraySize
```
public int valueArraySize(java.lang.Object vals)
```
  - valueArrayEmpty
```
public java.lang.Object valueArrayEmpty()
```
  - valueArrayPut
```
public java.lang.Object valueArrayPut(java.lang.Object vals,
                                      int pos,
                                      A newValue)
```
  - valueArrayUpdateVal
```
public java.lang.Object valueArrayUpdateVal(java.lang.Object vals,
                                            int pos,
                                            A newValue)
```
  - valueArrayFromArray
```
public java.lang.Object valueArrayFromArray(java.lang.Object[] objects)
```
  - valueArrayCopyOfRange
```
public java.lang.Object valueArrayCopyOfRange(java.lang.Object vals,
                                              int from,
                                              int to)
```
  - valueArrayDeleteValue
```
public java.lang.Object valueArrayDeleteValue(java.lang.Object vals,
                                              int pos)
```
  - getBTreeKeySerializer
```
public BTreeKeySerializer getBTreeKeySerializer(java.util.Comparator comparator)
```

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All Classes

Summary:
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Field |
Constr |
Method

Detail:
Field |
Constr |
Method

Class Serializer<A>

Nested Class Summary

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CHAR

STRING_XXHASH

STRING

STRING_INTERN

STRING_ASCII

STRING_NOSIZE

LONG

LONG_PACKED

LONG_PACKED_ZIGZAG

INTEGER

INTEGER_PACKED

INTEGER_PACKED_ZIGZAG

BOOLEAN

RECID

RECID_ARRAY

ILLEGAL_ACCESS

BYTE_ARRAY

BYTE_ARRAY_NOSIZE

CHAR_ARRAY

INT_ARRAY

LONG_ARRAY

DOUBLE_ARRAY

JAVA

UUID

BYTE

FLOAT

DOUBLE

SHORT

BOOLEAN_ARRAY

SHORT_ARRAY

FLOAT_ARRAY

BIG_INTEGER

BIG_DECIMAL

CLASS

DATE

BASIC

Constructor Detail

Serializer

Method Detail

serialize

deserialize

fixedSize

isTrusted

equals

hashCode

valueArraySerialize

valueArrayDeserialize

valueArrayGet

valueArraySize

valueArrayEmpty

valueArrayPut

valueArrayUpdateVal

valueArrayFromArray

valueArrayCopyOfRange

valueArrayDeleteValue

getBTreeKeySerializer