public interface Blob
Two blobs are considered equal in terms of
if they contain the same sequences of bytes. Implementations can optimize
the equality checks by using strong hash codes or other similar means as
long as they comply with the above definition of equality.
Due to their nature blobs should not be used as keys in hash tables.
To highlight that and to ensure semantic correctness of the equality
contract across different blob implementations, the
method of all blob instances should return zero.
|Modifier and Type||Method and Description|
A unique identifier of the content of this value.
Returns a new stream for this blob.
Returns a secure reference to this blob, or
Returns the length of this blob or -1 if unknown.
readreturn the same sequence of bytes as long as neither call throws an exception.
nullif such a reference is not available.
This method returns null if the identifier is unknown. The identifier may not always be available, for example if the value has not yet been saved or processed. Once an identifier is available, it will never change because values are immutable.
If two values have the same identifier, the content of the value is guaranteed to be the same. However it is not guaranteed that two values with the same content will return the same identifier.
The identifier is opaque, meaning it can have any format and size.
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