java.lang.Object
- org.apache.flink.iteration.datacache.nonkeyed.DataCacheSnapshot

```
public class DataCacheSnapshot
extends Object
```
The snapshot of a data cache. It could be written out or read from an external stream.

构造器概要

构造器
构造器	说明
`DataCacheSnapshot(org.apache.flink.core.fs.FileSystem fileSystem, org.apache.flink.api.java.tuple.Tuple2<Integer,Integer> readerPosition, List<Segment> segments)`

方法概要

所有方法静态方法实例方法具体方法
修饰符和类型	方法	说明
`org.apache.flink.core.fs.FileSystem`	`getFileSystem()`
`org.apache.flink.api.java.tuple.Tuple2<Integer,Integer>`	`getReaderPosition()`
`List<Segment>`	`getSegments()`
`static DataCacheSnapshot`	`recover(InputStream checkpointInputStream, org.apache.flink.core.fs.FileSystem fileSystem, org.apache.flink.util.function.SupplierWithException<org.apache.flink.core.fs.Path,IOException> pathGenerator)`	Recovers a data cache instance from the input stream.
`static <T> void`	`replay(InputStream checkpointInputStream, org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer, org.apache.flink.statefun.flink.core.feedback.FeedbackConsumer<T> feedbackConsumer)`	Replays cached records in the data cache from the input stream into the target feedback consumer.
`<T> void`	`tryReadSegmentsToMemory(org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer, org.apache.flink.table.runtime.util.MemorySegmentPool segmentPool)`	Attempts to cache the segments in memory.
`void`	`writeTo(OutputStream checkpointOutputStream)`	Writes the information about this data cache to an output stream.

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

DataCacheSnapshot

public DataCacheSnapshot(org.apache.flink.core.fs.FileSystem fileSystem,
                         @Nullable
                         org.apache.flink.api.java.tuple.Tuple2<Integer,Integer> readerPosition,
                         List<Segment> segments)

方法详细资料

getFileSystem

public org.apache.flink.core.fs.FileSystem getFileSystem()

getReaderPosition

@Nullable
public org.apache.flink.api.java.tuple.Tuple2<Integer,Integer> getReaderPosition()

getSegments
```
public List<Segment> getSegments()
```

writeTo

public void writeTo(OutputStream checkpointOutputStream)
             throws IOException

Writes the information about this data cache to an output stream.

抛出:: IOException

replay

public static <T> void replay(InputStream checkpointInputStream,
                              org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer,
                              org.apache.flink.statefun.flink.core.feedback.FeedbackConsumer<T> feedbackConsumer)
                       throws Exception

Replays cached records in the data cache from the input stream into the target feedback consumer.

抛出:: Exception

recover

public static DataCacheSnapshot recover(InputStream checkpointInputStream,
                                        org.apache.flink.core.fs.FileSystem fileSystem,
                                        org.apache.flink.util.function.SupplierWithException<org.apache.flink.core.fs.Path,IOException> pathGenerator)
                                 throws IOException

Recovers a data cache instance from the input stream.

抛出:: IOException

tryReadSegmentsToMemory
```
public <T> void tryReadSegmentsToMemory(org.apache.flink.api.common.typeutils.TypeSerializer<T> serializer,
                                        org.apache.flink.table.runtime.util.MemorySegmentPool segmentPool)
                                 throws IOException
```
Attempts to cache the segments in memory.
The attempt is made at segment granularity, which means there might be only part of the segments are cached.
This method does not throw exceptions if there is not enough memory space for caching a segment.

抛出:

IOException

类 DataCacheSnapshot