public final class BytewiseComparator extends AbstractComparator
Slice
The performance of Comparators implemented in Java is always
less than their C++ counterparts due to the bridging overhead,
as such you likely don't want to use this apart from benchmarking
and you most likely instead wanted
BuiltinComparator.BYTEWISE_COMPARATORnativeHandle_owningHandle_| 构造器和说明 |
|---|
BytewiseComparator(ComparatorOptions copt) |
| 限定符和类型 | 方法和说明 |
|---|---|
int |
compare(java.nio.ByteBuffer a,
java.nio.ByteBuffer b)
Three-way key comparison.
|
void |
findShortestSeparator(java.nio.ByteBuffer start,
java.nio.ByteBuffer limit)
Used to reduce the space requirements
for internal data structures like index blocks.
|
void |
findShortSuccessor(java.nio.ByteBuffer key)
Used to reduce the space requirements
for internal data structures like index blocks.
|
java.lang.String |
name()
The name of the comparator.
|
initializeNative, usingDirectBuffersdisposeInternalclose, disOwnNativeHandle, isOwningHandlepublic BytewiseComparator(ComparatorOptions copt)
public java.lang.String name()
AbstractComparatorA new name should be used whenever the comparator implementation changes in a way that will cause the relative ordering of any two keys to change.
Names starting with "rocksdb." are reserved and should not be used.
name 在类中 AbstractComparatorpublic int compare(java.nio.ByteBuffer a,
java.nio.ByteBuffer b)
AbstractComparatorByteBuffers passed in, though
it would be unconventional to modify the "limit" or any of the
underlying bytes. As a callback, RocksJava will ensure that a
is a different instance from b.compare 在类中 AbstractComparatora - buffer containing the first key in its "remaining" elementsb - buffer containing the second key in its "remaining" elementspublic void findShortestSeparator(java.nio.ByteBuffer start,
java.nio.ByteBuffer limit)
AbstractComparatorUsed to reduce the space requirements for internal data structures like index blocks.
If start < limit, you may modify start which is a shorter string in [start, limit).
If you modify start, it is expected that you set the byte buffer so that a subsequent read of start.remaining() bytes from start.position() to start.limit() will obtain the new start value.Simple comparator implementations may return with start unchanged. i.e., an implementation of this method that does nothing is correct.
findShortestSeparator 在类中 AbstractComparatorstart - the startlimit - the limitpublic void findShortSuccessor(java.nio.ByteBuffer key)
AbstractComparatorUsed to reduce the space requirements for internal data structures like index blocks.
You may change key to a shorter key (key1) where key1 ≥ key.
Simple comparator implementations may return the key unchanged. i.e., an implementation of this method that does nothing is correct.
findShortSuccessor 在类中 AbstractComparatorkey - the key