org.rocksdb

类 AbstractRocksIterator<P extends RocksObject>

java.lang.Object

org.rocksdb.AbstractNativeReference

org.rocksdb.AbstractImmutableNativeReference

org.rocksdb.RocksObject

org.rocksdb.AbstractRocksIterator<P>

类型参数:

P - The type of the Parent Object from which the Rocks Iterator was created. This is used by disposeInternal to avoid double-free issues with the underlying C++ object.

所有已实现的接口:

java.lang.AutoCloseable, RocksIteratorInterface

直接已知子类:

RocksIterator, SstFileReaderIterator, WBWIRocksIterator

public abstract class AbstractRocksIterator<P extends RocksObject>
extends RocksObject
implements RocksIteratorInterface

Base class implementation for Rocks Iterators in the Java API

Multiple threads can invoke const methods on an RocksIterator without external synchronization, but if any of the threads may call a non-const method, all threads accessing the same RocksIterator must use external synchronization.

另请参阅:

RocksObject

字段概要

从类继承的字段 org.rocksdb.RocksObject

nativeHandle_

从类继承的字段 org.rocksdb.AbstractImmutableNativeReference

owningHandle_

构造器概要

构造器

限定符	构造器和说明
protected	AbstractRocksIterator(P parent, long nativeHandle)

方法概要

限定符和类型	方法和说明
protected void	disposeInternal() Deletes underlying C++ iterator pointer.
boolean	isValid() An iterator is either positioned at an entry, or not valid.
void	next() Moves to the next entry in the source.
void	prev() Moves to the previous entry in the source.
void	refresh() If supported, renew the iterator to represent the latest state.
void	seek(byte[] target) Position at the first entry in the source whose key is at or past target.
void	seek(java.nio.ByteBuffer target) Position at the first entry in the source whose key is that or past target.
void	seekForPrev(byte[] target) Position at the first entry in the source whose key is that or before target.
void	seekForPrev(java.nio.ByteBuffer target) Position at the last key that is less than or equal to the target key.
void	seekToFirst() Position at the first entry in the source.
void	seekToLast() Position at the last entry in the source.
void	status() If an error has occurred, return it.

从类继承的方法 org.rocksdb.RocksObject

disposeInternal, getNativeHandle

从类继承的方法 org.rocksdb.AbstractImmutableNativeReference

close, disOwnNativeHandle, isOwningHandle

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

构造器详细资料

AbstractRocksIterator

protected AbstractRocksIterator(P parent,
                                long nativeHandle)

方法详细资料

isValid

public boolean isValid()

从接口复制的说明: RocksIteratorInterface

An iterator is either positioned at an entry, or not valid. This method returns true if the iterator is valid.

指定者:

isValid 在接口中 RocksIteratorInterface

返回:

true if iterator is valid.

seekToFirst

public void seekToFirst()

从接口复制的说明: RocksIteratorInterface

Position at the first entry in the source. The iterator is Valid() after this call if the source is not empty.

指定者:

seekToFirst 在接口中 RocksIteratorInterface

seekToLast

public void seekToLast()

从接口复制的说明: RocksIteratorInterface

Position at the last entry in the source. The iterator is valid after this call if the source is not empty.

指定者:

seekToLast 在接口中 RocksIteratorInterface

seek

public void seek(byte[] target)

从接口复制的说明: RocksIteratorInterface

Position at the first entry in the source whose key is at or past target.

The iterator is valid after this call if the source contains a key that comes at or past target.

指定者:

seek 在接口中 RocksIteratorInterface

参数:

target - byte array describing a key or a key prefix to seek for.

seekForPrev

public void seekForPrev(byte[] target)

从接口复制的说明: RocksIteratorInterface

Position at the first entry in the source whose key is that or before target.

The iterator is valid after this call if the source contains a key that comes at or before target.

指定者:

seekForPrev 在接口中 RocksIteratorInterface

参数:

target - byte array describing a key or a key prefix to seek for.

seek

public void seek(java.nio.ByteBuffer target)

从接口复制的说明: RocksIteratorInterface

Position at the first entry in the source whose key is that or past target.

The iterator is valid after this call if the source contains a key that comes at or past target.

指定者:

seek 在接口中 RocksIteratorInterface

参数:

target - byte array describing a key or a key prefix to seek for. Supports direct buffer only.

seekForPrev

public void seekForPrev(java.nio.ByteBuffer target)

从接口复制的说明: RocksIteratorInterface

Position at the last key that is less than or equal to the target key.

The iterator is valid after this call if the source contains a key that comes at or past target.

指定者:

seekForPrev 在接口中 RocksIteratorInterface

参数:

target - byte array describing a key or a key prefix to seek for. Supports direct buffer only.

next

public void next()

从接口复制的说明: RocksIteratorInterface

Moves to the next entry in the source. After this call, Valid() is true if the iterator was not positioned at the last entry in the source.

REQUIRES: RocksIteratorInterface.isValid()

指定者:

next 在接口中 RocksIteratorInterface

prev

public void prev()

从接口复制的说明: RocksIteratorInterface

Moves to the previous entry in the source. After this call, Valid() is true if the iterator was not positioned at the first entry in source.

REQUIRES: RocksIteratorInterface.isValid()

指定者:

prev 在接口中 RocksIteratorInterface

refresh

public void refresh()
             throws RocksDBException

从接口复制的说明: RocksIteratorInterface

If supported, renew the iterator to represent the latest state. The iterator will be invalidated after the call. Not supported if ReadOptions.setSnapshot(Snapshot) was specified when creating the iterator.

指定者:

refresh 在接口中 RocksIteratorInterface

抛出:

RocksDBException - thrown if the operation is not supported or an error happens in the underlying native library

status

public void status()
            throws RocksDBException

从接口复制的说明: RocksIteratorInterface

If an error has occurred, return it. Else return an ok status. If non-blocking IO is requested and this operation cannot be satisfied without doing some IO, then this returns Status::Incomplete().

指定者:

status 在接口中 RocksIteratorInterface

抛出:

RocksDBException - thrown if error happens in underlying native library.

disposeInternal

protected void disposeInternal()

Deletes underlying C++ iterator pointer.

Note: the underlying handle can only be safely deleted if the parent instance related to a certain RocksIterator is still valid and initialized. Therefore disposeInternal() checks if the parent is initialized before freeing the native handle.

覆盖:

disposeInternal 在类中 RocksObject