Data (OpenHFT/Chronicle-Map 3.5.0-rc API)

Type Parameters:

T - type of the accessed objects

All Known Implementing Classes:

AbstractData
```
public interface Data<T>
```
Dual bytes/object access to keys/values/elements.
Bytes access: bytes() + offset() + size().
Object access: get().
In most cases, each particular value wraps either some object or some bytes. Object is marshalled to bytes lazily on demand, and bytes are lazily deserialized to object, accordingly.

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method and Description
`RandomDataInput`	`bytes()` Returns the accessor object to the `Data`'s bytes.
`static boolean`	`bytesEquivalent(Data<?> d1, Data<?> d2)` Utility method, compares two `Data` instances represent equivalent bytes sequences: by comparing their sizes, then calling `d1.equivalent(d2.bytes(), d2.offset())`.
`default boolean`	`dataEquals(Object obj)` `Data` implementations should override `Object.equals(Object)` with delegation to this method.
`default int`	`dataHashCode()` `Data` implementations should override `Object.hashCode()` with delegation to this method.
`default boolean`	`equivalent(RandomDataInput source, long sourceOffset)` Compares bytes of this `Data` to the given bytes `source`, starting from the given offset.
`T`	`get()` Returns "cached" object, generally not eligible for using outside some context, or a block, synchronized with locks, or lambda, etc.
`T`	`getUsing(T using)` Reads the object from the value's bytes, trying to reuse the given object (might be `null`).
`default long`	`hash(LongHashFunction f)` Computes hash code on the bytes representation of this `Data`, using the given hash function.
`long`	`offset()` Returns the offset to the `Data`'s bytes sequence, within the `bytes()` object.
`long`	`size()` Returns the size of this `Data`'s bytes sequence.
`default void`	`writeTo(RandomDataOutput target, long targetOffset)` Writes bytes of this `Data` to the given `target` from the given `targetOffset`.

- Method Detail
  - bytes
```
RandomDataInput bytes()
```
    Returns the accessor object to the Data's bytes. For safety, this interface returns read-only object, because this object could expose bytes source that must be immutable, e. g. an array behind String object.
  - offset
```
long offset()
```
    Returns the offset to the Data's bytes sequence, within the bytes() object. For example, the first byte of the bytes representation of this Data instance is data.bytes().readByte(data.offset()).
  - size
```
long size()
```
    Returns the size of this Data's bytes sequence. It spans from offset() to offset() + size() - 1 bytes within the bytes() object.
  - hash
```
default long hash(LongHashFunction f)
```
    Computes hash code on the bytes representation of this Data, using the given hash function.
    
    Parameters:
    
    f - the hash function to compute hash code using
    
    Returns:
    
    the hash code of this Data's bytes, computed by the given function
  - equivalent
```
default boolean equivalent(RandomDataInput source,
                           long sourceOffset)
```
    Compares bytes of this Data to the given bytes source, starting from the given offset.
    Default implementation compares bytes() of this Data, but custom implementation may only check if object of this Data would be serialized to the same bytes sequence, if this Data is object-based and obtaining bytes() requires serialization internally.
    
    Parameters:
    
    source - the bytes source, to compare this Data's bytes with
    
    sourceOffset - the offset in the bytes source, the bytes sequence starts from
    
    Returns:
    
    true if the given bytes sequence is equivalent to this Data's bytes, byte-by-byte
  - writeTo
```
default void writeTo(RandomDataOutput target,
                     long targetOffset)
```
    Writes bytes of this Data to the given target from the given targetOffset.
    Default implementation copies bytes() of this Data using standard IO methods of RandomDataInput and RandomDataOutput, but custom implementation may write directly from object, if this Data is object-based and obtaining bytes() requires serialization internally. This allows to avoid double copy.
    
    Parameters:
    
    target - the destination to write this data bytes to
    
    targetOffset - the offset in the target, to write the bytes from.
  - get
```
T get()
```
    Returns "cached" object, generally not eligible for using outside some context, or a block, synchronized with locks, or lambda, etc.
    If the Data is object wrapper -- this method just returns this object.
  - getUsing
```
T getUsing(@Nullable
           T using)
```
    Reads the object from the value's bytes, trying to reuse the given object (might be null).
  - bytesEquivalent
```
static boolean bytesEquivalent(Data<?> d1,
                               Data<?> d2)
```
    Utility method, compares two Data instances represent equivalent bytes sequences: by comparing their sizes, then calling d1.equivalent(d2.bytes(), d2.offset()).
    
    Parameters:
    
    d1 - the first Data to compare
    
    d2 - the second Data to compare
    
    Returns:
    
    if the given Data instances represent equivalent bytes sequences
  - dataHashCode
```
default int dataHashCode()
```
    Data implementations should override Object.hashCode() with delegation to this method. Computes value's hash code by applying a hash function to Data's bytes representation.
  - dataEquals
```
default boolean dataEquals(Object obj)
```
    Data implementations should override Object.equals(Object) with delegation to this method. Compares Datas' bytes representations.

Interface Data<T>

Method Summary

Method Detail

bytes

offset

size

hash

equivalent

writeTo

get

getUsing

bytesEquivalent

dataHashCode

dataEquals