org.apache.hadoop.fs.s3a.impl

Class ChangeTracker

java.lang.Object

org.apache.hadoop.fs.s3a.impl.ChangeTracker

@InterfaceAudience.Private
 @InterfaceStability.Unstable
public class ChangeTracker
extends Object

Change tracking for input streams: the revision ID/etag the previous request is recorded and when the next request comes in, it is compared. Self-contained for testing and use in different streams.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CHANGE_REPORTED_BY_S3

Constructor Summary

Constructors

Constructor and Description
ChangeTracker(String uri, ChangeDetectionPolicy policy, AtomicLong versionMismatches) Create a change tracker.

Method Summary

Modifier and Type	Method and Description
String	getRevisionId()
ChangeDetectionPolicy.Source	getSource()
AtomicLong	getVersionMismatches()
boolean	maybeApplyConstraint(com.amazonaws.services.s3.model.GetObjectRequest request) Apply any revision control set by the policy if it is to be enforced on the server.
void	processResponse(com.amazonaws.services.s3.model.S3Object object, String operation, long pos) Process the response from the server for validation against the change policy.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

CHANGE_REPORTED_BY_S3

public static final String CHANGE_REPORTED_BY_S3

See Also:

Constant Field Values

Constructor Detail

ChangeTracker

public ChangeTracker(String uri,
                     ChangeDetectionPolicy policy,
                     AtomicLong versionMismatches)

Create a change tracker.

Parameters:

uri - URI of object being tracked

policy - policy to track.

versionMismatches - reference to the version mismatch counter

Method Detail

getRevisionId

public String getRevisionId()

getSource

public ChangeDetectionPolicy.Source getSource()

getVersionMismatches

public AtomicLong getVersionMismatches()

maybeApplyConstraint

public boolean maybeApplyConstraint(com.amazonaws.services.s3.model.GetObjectRequest request)

Apply any revision control set by the policy if it is to be enforced on the server.

Parameters:

request - request to modify

Returns:

true iff a constraint was added.

processResponse

public void processResponse(com.amazonaws.services.s3.model.S3Object object,
                            String operation,
                            long pos)
                     throws org.apache.hadoop.fs.PathIOException

Process the response from the server for validation against the change policy.

Parameters:

object - object returned; may be null.

operation - operation in progress.

pos - offset of read

Throws:

org.apache.hadoop.fs.PathIOException - raised on failure

RemoteFileChangedException - if the remote file has changed.

toString

public String toString()

Overrides:

toString in class Object