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 version ID or etag of the object is tracked and compared on open/re-open. An initial version ID or etag may or may not be available, depending on usage (e.g. if S3Guard is utilized). Self-contained for testing and use in different streams.

Field Summary

Fields

Modifier and Type	Field and Description
static String	CHANGE_REPORTED_BY_S3
static int	SC_PRECONDITION_FAILED 412 Precondition Failed (HTTP/1.1 - RFC 2616)

Constructor Summary

Constructors

Constructor and Description
ChangeTracker(String uri, ChangeDetectionPolicy policy, ChangeTrackerStatistics versionMismatches, S3ObjectAttributes s3ObjectAttributes) Create a change tracker.

Method Summary

Modifier and Type	Method and Description
String	getRevisionId()
ChangeDetectionPolicy.Source	getSource()
long	getVersionMismatches()
boolean	maybeApplyConstraint(com.amazonaws.services.s3.model.CopyObjectRequest request) Apply any revision control set by the policy if it is to be enforced on the server.
boolean	maybeApplyConstraint(com.amazonaws.services.s3.model.GetObjectMetadataRequest request)
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	processException(com.amazonaws.SdkBaseException e, String operation) Process an exception generated against the change policy.
void	processMetadata(com.amazonaws.services.s3.model.ObjectMetadata metadata, String operation) Process metadata response from server for validation against the change policy.
void	processResponse(com.amazonaws.services.s3.transfer.model.CopyResult copyResult) Process the response from the server for validation against the change policy.
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

SC_PRECONDITION_FAILED

public static final int SC_PRECONDITION_FAILED

412 Precondition Failed (HTTP/1.1 - RFC 2616)

See Also:

Constant Field Values

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,
                     ChangeTrackerStatistics versionMismatches,
                     S3ObjectAttributes s3ObjectAttributes)

Create a change tracker.

Parameters:

uri - URI of object being tracked

policy - policy to track.

versionMismatches - reference to the version mismatch counter

s3ObjectAttributes - attributes of the object, potentially including an eTag or versionId to match depending on policy

Method Detail

getRevisionId

public String getRevisionId()

getSource

public ChangeDetectionPolicy.Source getSource()

getVersionMismatches

public long 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.

maybeApplyConstraint

public boolean maybeApplyConstraint(com.amazonaws.services.s3.model.CopyObjectRequest 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.

maybeApplyConstraint

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

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.

processResponse

public void processResponse(com.amazonaws.services.s3.transfer.model.CopyResult copyResult)
                     throws org.apache.hadoop.fs.PathIOException

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

Parameters:

copyResult - result of a copy operation

Throws:

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

RemoteFileChangedException - if the remote file has changed.

processException

public void processException(com.amazonaws.SdkBaseException e,
                             String operation)
                      throws RemoteFileChangedException

Process an exception generated against the change policy. If the exception indicates the file has changed, this method throws RemoteFileChangedException with the original exception as the cause.

Parameters:

e - the exception

operation - the operation performed when the exception was generated (e.g. "copy", "read", "select").

Throws:

RemoteFileChangedException - if the remote file has changed.

processMetadata

public void processMetadata(com.amazonaws.services.s3.model.ObjectMetadata metadata,
                            String operation)
                     throws org.apache.hadoop.fs.PathIOException

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

Parameters:

metadata - metadata returned from server

operation - operation in progress

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