com.google.cloud.hadoop.gcsio

Interface GoogleCloudStorage

All Known Implementing Classes:

ForwardingGoogleCloudStorage, GoogleCloudStorageImpl, InMemoryGoogleCloudStorage, PerformanceCachingGoogleCloudStorage, ThrottledGoogleCloudStorage

public interface GoogleCloudStorage

Interface for exposing the Google Cloud Storage API behavior in a way more amenable to writing filesystem semantics on top of it, without having to deal with API-specific considerations such as HttpTransports, credentials, network errors, batching, etc.

Please read the following document to get familiarity with basic GCS concepts: https://developers.google.com/storage/docs/concepts-techniques

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	GoogleCloudStorage.ListPage<T> Paged list request response

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_COMPOSE_OBJECTS The maximum number of objects that can be composed in one operation.
static long	MAX_RESULTS_UNLIMITED Value indicating all objects should be returned from GCS, no limit.
static java.lang.String	PATH_DELIMITER

Method Summary

Modifier and Type	Method and Description
void	close() Releases resources used by this instance.
void	compose(java.lang.String bucketName, java.util.List<java.lang.String> sources, java.lang.String destination, java.lang.String contentType) Composes inputs into a single GCS object.
GoogleCloudStorageItemInfo	composeObjects(java.util.List<StorageResourceId> sources, StorageResourceId destination, CreateObjectOptions options) Composes inputs into a single GCS object.
void	copy(java.lang.String srcBucketName, java.util.List<java.lang.String> srcObjectNames, java.lang.String dstBucketName, java.util.List<java.lang.String> dstObjectNames) Copies metadata of the given objects.
java.nio.channels.WritableByteChannel	create(StorageResourceId resourceId) Creates and opens an object for writing.
java.nio.channels.WritableByteChannel	create(StorageResourceId resourceId, CreateObjectOptions options) Creates and opens an object for writing.
void	create(java.lang.String bucketName) Creates a bucket.
void	create(java.lang.String bucketName, CreateBucketOptions options) Creates a bucket.
void	createEmptyObject(StorageResourceId resourceId) Creates an empty object, useful for placeholders representing, for example, directories.
void	createEmptyObject(StorageResourceId resourceId, CreateObjectOptions options) Creates an empty object, useful for placeholders representing, for example, directories.
void	createEmptyObjects(java.util.List<StorageResourceId> resourceIds) Creates a list of empty objects; see createEmptyObject(StorageResourceId) for the single-item version of this method.
void	createEmptyObjects(java.util.List<StorageResourceId> resourceIds, CreateObjectOptions options) Creates a list of empty objects; see createEmptyObject(StorageResourceId) for the single-item version of this method.
void	deleteBuckets(java.util.List<java.lang.String> bucketNames) Deletes a list of buckets.
void	deleteObjects(java.util.List<StorageResourceId> fullObjectNames) Deletes the given objects.
GoogleCloudStorageItemInfo	getItemInfo(StorageResourceId resourceId) Gets information about an object or a bucket.
java.util.List<GoogleCloudStorageItemInfo>	getItemInfos(java.util.List<StorageResourceId> resourceIds) Gets information about multiple objects and/or buckets.
GoogleCloudStorageOptions	getOptions() Retrieve the options that were used to create this GoogleCloudStorage.
java.util.List<GoogleCloudStorageItemInfo>	listBucketInfo() Gets a list of GoogleCloudStorageItemInfo for all buckets of this project.
java.util.List<java.lang.String>	listBucketNames() Gets a list of names of buckets in this project.
java.util.List<GoogleCloudStorageItemInfo>	listObjectInfo(java.lang.String bucketName, java.lang.String objectNamePrefix, java.lang.String delimiter) Same name-matching semantics as listObjectNames(java.lang.String, java.lang.String, java.lang.String) except this method retrieves the full GoogleCloudStorageFileInfo for each item as well.
java.util.List<GoogleCloudStorageItemInfo>	listObjectInfo(java.lang.String bucketName, java.lang.String objectNamePrefix, java.lang.String delimiter, long maxResults) Same name-matching semantics as listObjectNames(java.lang.String, java.lang.String, java.lang.String) except this method retrieves the full GoogleCloudStorageFileInfo for each item as well.
GoogleCloudStorage.ListPage<GoogleCloudStorageItemInfo>	listObjectInfoPage(java.lang.String bucketName, java.lang.String objectNamePrefix, java.lang.String delimiter, java.lang.String pageToken) The same semantics as listObjectInfo(java.lang.String, java.lang.String, java.lang.String), but returns only result of single list request (1 page).
java.util.List<java.lang.String>	listObjectNames(java.lang.String bucketName, java.lang.String objectNamePrefix, java.lang.String delimiter) Gets names of objects contained in the given bucket and whose names begin with the given prefix.
java.util.List<java.lang.String>	listObjectNames(java.lang.String bucketName, java.lang.String objectNamePrefix, java.lang.String delimiter, long maxResults) Gets names of objects contained in the given bucket and whose names begin with the given prefix.
java.nio.channels.SeekableByteChannel	open(StorageResourceId resourceId) Opens an object for reading.
java.nio.channels.SeekableByteChannel	open(StorageResourceId resourceId, GoogleCloudStorageReadOptions readOptions) Opens an object for reading.
java.util.List<GoogleCloudStorageItemInfo>	updateItems(java.util.List<UpdatableItemInfo> itemInfoList) Attempt to update metadata of the objects referenced within the passed itemInfo objects.
void	waitForBucketEmpty(java.lang.String bucketName) Waits for the given bucket to be empty.

Field Detail

PATH_DELIMITER

static final java.lang.String PATH_DELIMITER

See Also:

Constant Field Values

MAX_RESULTS_UNLIMITED

static final long MAX_RESULTS_UNLIMITED

Value indicating all objects should be returned from GCS, no limit.

See Also:

Constant Field Values

MAX_COMPOSE_OBJECTS

static final int MAX_COMPOSE_OBJECTS

The maximum number of objects that can be composed in one operation.

See Also:

Constant Field Values

Method Detail

getOptions

GoogleCloudStorageOptions getOptions()

Retrieve the options that were used to create this GoogleCloudStorage.

create

java.nio.channels.WritableByteChannel create(StorageResourceId resourceId)
                                      throws java.io.IOException

Creates and opens an object for writing. The bucket must already exist. If the object already exists and resourceId doesn't have a explicit generationId set, it is deleted. If a generationId is provided in resourceId, that is used in place of normal overwrite semantics (overwrite will only succeed if the provided generationId matches the existing object, where a generationId of 0 indicates no existing object expected).

Parameters:

resourceId - identifies a StorageObject

Returns:

a channel for writing to the given object

Throws:

java.io.IOException - on IO error

create

java.nio.channels.WritableByteChannel create(StorageResourceId resourceId,
                                             CreateObjectOptions options)
                                      throws java.io.IOException

Creates and opens an object for writing. The bucket must already exist. If resourceId contains a known generationId or a generationId of 0, it is used instead of any "overwrite" settings in the provided CreateObjectOptions (overwrite will only succeed if the provided generationId matches the existing object, where a generationId of 0 indicates no existing object expected).

Parameters:

resourceId - identifies a StorageObject

options - Options to use when creating the object

Returns:

a channel for writing to the given object

Throws:

java.io.IOException - on IO error

createEmptyObject

void createEmptyObject(StorageResourceId resourceId)
                throws java.io.IOException

Creates an empty object, useful for placeholders representing, for example, directories. The bucket must already exist. If the object already exists, it is overwritten. See create(StorageResourceId) for the behavior if StorageResourceId.getGenerationId() is explicitly set.

Parameters:

resourceId - identifies a StorageObject

Throws:

java.io.IOException - on IO error

createEmptyObject

void createEmptyObject(StorageResourceId resourceId,
                       CreateObjectOptions options)
                throws java.io.IOException

Creates an empty object, useful for placeholders representing, for example, directories. The bucket must already exist. If the object already exists, it is overwritten. See create(StorageResourceId) for the behavior if StorageResourceId.getGenerationId() is explicitly set.

Parameters:

resourceId - identifies a StorageObject

options - options to use when creating the object

Throws:

java.io.IOException - on IO error

createEmptyObjects

void createEmptyObjects(java.util.List<StorageResourceId> resourceIds)
                 throws java.io.IOException

Creates a list of empty objects; see createEmptyObject(StorageResourceId) for the single-item version of this method. Implementations may use different flow than the single-item version for greater efficiency. See create(StorageResourceId) for the behavior if StorageResourceId.getGenerationId() is explicitly set.

Throws:

java.io.IOException

createEmptyObjects

void createEmptyObjects(java.util.List<StorageResourceId> resourceIds,
                        CreateObjectOptions options)
                 throws java.io.IOException

Creates a list of empty objects; see createEmptyObject(StorageResourceId) for the single-item version of this method. Implementations may use different flow than the single-item version for greater efficiency. See create(StorageResourceId) for the behavior if StorageResourceId.getGenerationId() is explicitly set.

Throws:

java.io.IOException

open

java.nio.channels.SeekableByteChannel open(StorageResourceId resourceId)
                                    throws java.io.IOException

Opens an object for reading.

Parameters:

resourceId - identifies a StorageObject

Returns:

a channel for reading from the given object

Throws:

java.io.FileNotFoundException - if the given object does not exist

java.io.IOException - if object exists but cannot be opened

open

java.nio.channels.SeekableByteChannel open(StorageResourceId resourceId,
                                           GoogleCloudStorageReadOptions readOptions)
                                    throws java.io.IOException

Opens an object for reading.

Parameters:

resourceId - identifies a StorageObject

readOptions - Fine-grained options for behaviors of retries, buffering, etc.

Returns:

a channel for reading from the given object

Throws:

java.io.FileNotFoundException - if the given object does not exist

java.io.IOException - if object exists but cannot be opened

create

void create(java.lang.String bucketName)
     throws java.io.IOException

Creates a bucket.

Parameters:

bucketName - name of the bucket to create

Throws:

java.io.IOException - on IO error

create

void create(java.lang.String bucketName,
            CreateBucketOptions options)
     throws java.io.IOException

Creates a bucket.

Parameters:

bucketName - name of the bucket to create

options - options to use when creating bucket

Throws:

java.io.IOException - on IO error

deleteBuckets

void deleteBuckets(java.util.List<java.lang.String> bucketNames)
            throws java.io.IOException

Deletes a list of buckets. Does not throw any exception for "bucket not found" errors.

Parameters:

bucketNames - name of the buckets to delete

Throws:

java.io.FileNotFoundException - if the given bucket does not exist

java.io.IOException - on IO error

deleteObjects

void deleteObjects(java.util.List<StorageResourceId> fullObjectNames)
            throws java.io.IOException

Deletes the given objects. Does not throw any exception for "object not found" errors.

Parameters:

fullObjectNames - names of objects to delete with their respective bucketNames.

Throws:

java.io.FileNotFoundException - if the given object does not exist

java.io.IOException - if object exists but cannot be deleted

copy

void copy(java.lang.String srcBucketName,
          java.util.List<java.lang.String> srcObjectNames,
          java.lang.String dstBucketName,
          java.util.List<java.lang.String> dstObjectNames)
   throws java.io.IOException

Copies metadata of the given objects. After the copy is successfully complete, each object blob is reachable by two different names. Copying between two different locations or between two different storage classes is not allowed.

Parameters:

srcBucketName - name of the bucket containing the objects to copy

srcObjectNames - names of the objects to copy

dstBucketName - name of the bucket to copy to

dstObjectNames - names of the objects after copy

Throws:

java.io.FileNotFoundException - if the source object or the destination bucket does not exist

java.io.IOException - in all other error cases

listBucketNames

java.util.List<java.lang.String> listBucketNames()
                                          throws java.io.IOException

Gets a list of names of buckets in this project.

Throws:

java.io.IOException

listBucketInfo

java.util.List<GoogleCloudStorageItemInfo> listBucketInfo()
                                                   throws java.io.IOException

Gets a list of GoogleCloudStorageItemInfo for all buckets of this project. This is no more expensive than calling listBucketNames(), since the list API for buckets already retrieves all the relevant bucket metadata.

Throws:

java.io.IOException

listObjectNames

java.util.List<java.lang.String> listObjectNames(java.lang.String bucketName,
                                                 java.lang.String objectNamePrefix,
                                                 java.lang.String delimiter)
                                          throws java.io.IOException

Gets names of objects contained in the given bucket and whose names begin with the given prefix.

Note: Although GCS does not implement a file system, it treats objects that contain a delimiter as different from other objects when listing objects. This will be clearer with an example.

Consider a bucket with objects: o1, d1/, d1/o1, d1/o2 With prefix == null and delimiter == /, we get: d1/, o1 With prefix == null and delimiter == null, we get: o1, d1/, d1/o1, d1/o2

Thus when delimiter is null, the entire key name is considered an opaque string, otherwise only the part up to the first delimiter is considered.

The default implementation of this method should turn around and call the version that takes maxResults so that inheriting classes need only implement that version.

Parameters:

bucketName - bucket name

objectNamePrefix - object name prefix or null if all objects in the bucket are desired

delimiter - delimiter to use (typically "/"), otherwise null

Returns:

list of object names

Throws:

java.io.IOException - on IO error

listObjectNames

java.util.List<java.lang.String> listObjectNames(java.lang.String bucketName,
                                                 java.lang.String objectNamePrefix,
                                                 java.lang.String delimiter,
                                                 long maxResults)
                                          throws java.io.IOException

Gets names of objects contained in the given bucket and whose names begin with the given prefix.

Note: Although GCS does not implement a file system, it treats objects that contain a delimiter as different from other objects when listing objects. This will be clearer with an example.

Consider a bucket with objects: o1, d1/, d1/o1, d1/o2 With prefix == null and delimiter == /, we get: d1/, o1 With prefix == null and delimiter == null, we get: o1, d1/, d1/o1, d1/o2

Thus when delimiter is null, the entire key name is considered an opaque string, otherwise only the part up to the first delimiter is considered.

Parameters:

bucketName - bucket name

objectNamePrefix - object name prefix or null if all objects in the bucket are desired

delimiter - delimiter to use (typically "/"), otherwise null

maxResults - maximum number of results to return, unlimited if negative or zero

Returns:

list of object names

Throws:

java.io.IOException - on IO error

listObjectInfo

java.util.List<GoogleCloudStorageItemInfo> listObjectInfo(java.lang.String bucketName,
                                                          java.lang.String objectNamePrefix,
                                                          java.lang.String delimiter)
                                                   throws java.io.IOException

Same name-matching semantics as listObjectNames(java.lang.String, java.lang.String, java.lang.String) except this method retrieves the full GoogleCloudStorageFileInfo for each item as well.

Generally the info is already available from the same "list()" calls, so the only additional cost is dispatching an extra batch request to retrieve object metadata for all listed directories, since these are originally listed as String prefixes without attached metadata.

The default implementation of this method should turn around and call the version that takes maxResults so that inheriting classes need only implement that version.

Parameters:

bucketName - bucket name

objectNamePrefix - object name prefix or null if all objects in the bucket are desired

delimiter - delimiter to use (typically "/"), otherwise null

Returns:

list of object info

Throws:

java.io.IOException - on IO error

listObjectInfo

java.util.List<GoogleCloudStorageItemInfo> listObjectInfo(java.lang.String bucketName,
                                                          java.lang.String objectNamePrefix,
                                                          java.lang.String delimiter,
                                                          long maxResults)
                                                   throws java.io.IOException

Same name-matching semantics as listObjectNames(java.lang.String, java.lang.String, java.lang.String) except this method retrieves the full GoogleCloudStorageFileInfo for each item as well.

Generally the info is already available from the same "list()" calls, so the only additional cost is dispatching an extra batch request to retrieve object metadata for all listed directories, since these are originally listed as String prefixes without attached metadata.

Parameters:

bucketName - bucket name

objectNamePrefix - object name prefix or null if all objects in the bucket are desired

delimiter - delimiter to use (typically "/"), otherwise null

maxResults - maximum number of results to return, unlimited if negative or zero

Returns:

list of object info

Throws:

java.io.IOException - on IO error

listObjectInfoPage

GoogleCloudStorage.ListPage<GoogleCloudStorageItemInfo> listObjectInfoPage(java.lang.String bucketName,
                                                                           java.lang.String objectNamePrefix,
                                                                           java.lang.String delimiter,
                                                                           java.lang.String pageToken)
                                                                    throws java.io.IOException

The same semantics as listObjectInfo(java.lang.String, java.lang.String, java.lang.String), but returns only result of single list request (1 page).

Parameters:

bucketName - bucket name

objectNamePrefix - object name prefix or null if all objects in the bucket are desired

delimiter - delimiter to use (typically "/"), otherwise null

pageToken - the page token

Returns:

GoogleCloudStorage.ListPage object with listed GoogleCloudStorageItemInfos and next page token if any

Throws:

java.io.IOException - on IO error

getItemInfo

GoogleCloudStorageItemInfo getItemInfo(StorageResourceId resourceId)
                                throws java.io.IOException

Gets information about an object or a bucket.

Parameters:

resourceId - identifies either root, a Bucket, or a StorageObject

Returns:

information about the given item

Throws:

java.io.IOException - on IO error

getItemInfos

java.util.List<GoogleCloudStorageItemInfo> getItemInfos(java.util.List<StorageResourceId> resourceIds)
                                                 throws java.io.IOException

Gets information about multiple objects and/or buckets. Items that are "not found" will still have an entry in the returned list; exists() will return false for these entries. The return list will have the same ordering as the input arguments.

Parameters:

resourceIds - names of the GCS StorageObjects or Buckets for which to retrieve info.

Returns:

information about the given resourceIds.

Throws:

java.io.IOException - on IO error

updateItems

java.util.List<GoogleCloudStorageItemInfo> updateItems(java.util.List<UpdatableItemInfo> itemInfoList)
                                                throws java.io.IOException

Attempt to update metadata of the objects referenced within the passed itemInfo objects.

Returns:

Updated GoogleCloudStorageItemInfo objects for the referenced objects.

Throws:

java.io.IOException - on IO error

close

void close()

Releases resources used by this instance.

waitForBucketEmpty

void waitForBucketEmpty(java.lang.String bucketName)
                 throws java.io.IOException

Waits for the given bucket to be empty. Note: GCS only supports eventual consistency of object lists. When a user deletes a top-level directory recursively, the fact that all items have gone away is not reflected instantly. We retry and wait for that to happen.

Throws:

java.io.IOException

compose

void compose(java.lang.String bucketName,
             java.util.List<java.lang.String> sources,
             java.lang.String destination,
             java.lang.String contentType)
      throws java.io.IOException

Composes inputs into a single GCS object. This performs a GCS Compose. Objects will be composed according to the order they appear in the input. The destination object, if already present, will be overwritten. Sources and destination are assumed to be in the same bucket.

Parameters:

bucketName - name of the bucket containing the sources and the destination

sources - names of the objects to be composed

destination - name of the resulting object

contentType - content-type of composed object

Throws:

java.io.IOException - if the Compose operation was unsuccessful

composeObjects

GoogleCloudStorageItemInfo composeObjects(java.util.List<StorageResourceId> sources,
                                          StorageResourceId destination,
                                          CreateObjectOptions options)
                                   throws java.io.IOException

Composes inputs into a single GCS object. This performs a GCS Compose. Objects will be composed according to the order they appear in the input. The destination object will have metadata set according to options. Overwrite semantics for the destination object will follow the same semantics as create(StorageResourceId, CreateObjectOptions). See create(StorageResourceId) for the behavior if StorageResourceId.getGenerationId() is explicitly set. The bucket must be the same for all sources and the destination.

Throws:

java.io.IOException