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Oracle® Fusion Middleware Java API Reference for Oracle Coherence 12c (12.1.3.0.0) E47890-01 |
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java.lang.Object
com.tangosol.io.BinaryDeltaCompressor
public class BinaryDeltaCompressor
A DeltaCompressor implementation that works with opaque (binary) values.
The delta format is composed of a leading byte that indicates the format; the format indicator byte is one of the FMT_* field values. If the delta value does not begin with one of the FMT_* indicators, then the delta value is itself the new value. If the delta is null, then it indicates no change. The grammar follows:
BinaryDelta: FMT_EMPTY FMT_BINDIFF BinaryChangeList-opt OP_TERM FMT_REPLACE-opt Bytes null BinaryChangeList: OP_EXTRACT Offset Length BinaryChangeList-opt OP_APPEND Length Bytes BinaryChangeList-opt Offset: Length: packed-integer Bytes: byte Bytes-opt
Field Summary | |
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protected static Binary |
DELTA_TRUNCATE A delta value that indicates an empty new value. |
protected static byte |
FMT_BINDIFF A format indicator (the first byte of the binary delta) that indicates that the new value is formed by applying a series of modifications to the old value. |
protected static byte |
FMT_EMPTY A format indicator (the first byte of the binary delta) that indicates that the new value is a zero-length binary value. |
protected static byte |
FMT_REPLACE A format indicator (the first byte of the binary delta) that indicates that the new value is found in its entirety in the delta value. |
protected static int |
MIN_BLOCK Minimum length of an "extract" block to encode. |
protected static Binary |
NO_BINARY An empty Binary object. |
protected static byte |
OP_APPEND A binary delta operator that instructs the applyDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer) method to copy the following bytes from the delta value and append them to the new value. |
protected static byte |
OP_EXTRACT A binary delta operator that instructs the applyDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer) method to extract bytes from the old value and append them to the new value. |
protected static byte |
OP_TERM A binary delta operator that instructs the applyDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer) method that the delta has been fully applied. |
Constructor Summary | |
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BinaryDeltaCompressor() Default constructor. |
Method Summary | |
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ReadBuffer |
applyDelta(ReadBuffer bufOld, ReadBuffer bufDelta) Apply a delta to an old value in order to create a new value. |
protected ReadBuffer |
createDelta(ReadBuffer bufOld, ReadBuffer bufNew) Actually create a delta in the binary delta format. |
ReadBuffer |
extractDelta(ReadBuffer bufOld, ReadBuffer bufNew) Compare an old value to a new value and generate a delta that represents the changes that must be made to the old value in order to transform it into the new value. |
Field Detail |
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protected static final byte FMT_EMPTY
protected static final byte FMT_REPLACE
protected static final byte FMT_BINDIFF
protected static final byte OP_EXTRACT
applyDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer)
method to extract bytes from the old value and append them to the new value. The format is the one-byte OP_EXTRACT indicator followed by a packed int offset and packed int length. The offset and length indicate the region of the old value to extract and append to the new value.
protected static final byte OP_APPEND
applyDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer)
method to copy the following bytes from the delta value and append them to the new value. The format is the one-byte OP_APPEND indicator followed by a packed int length and then a series of bytes. The length indicates the length of the series of bytes to copy from the delta value and append to the new value.
protected static final byte OP_TERM
applyDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer)
method that the delta has been fully applied.
protected static final int MIN_BLOCK
protected static final Binary NO_BINARY
protected static final Binary DELTA_TRUNCATE
Constructor Detail |
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public BinaryDeltaCompressor()
Method Detail |
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public ReadBuffer extractDelta(ReadBuffer bufOld, ReadBuffer bufNew)
If the old value is null, the generated delta must be a "replace", meaning that applying it to any value must produce the specified new value.
extractDelta
in interface DeltaCompressor
bufOld
- the old valuebufNew
- the new value; must not be nullpublic ReadBuffer applyDelta(ReadBuffer bufOld, ReadBuffer bufDelta)
applyDelta
in interface DeltaCompressor
bufOld
- the old valuebufDelta
- the delta information returned from DeltaCompressor.extractDelta(com.tangosol.io.ReadBuffer, com.tangosol.io.ReadBuffer)
to apply to the old valueprotected ReadBuffer createDelta(ReadBuffer bufOld, ReadBuffer bufNew)
bufOld
- the old valuebufNew
- the new value
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Oracle® Fusion Middleware Java API Reference for Oracle Coherence 12c (12.1.3.0.0) E47890-01 |
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