RawGcsService (App Engine Client for Google Cloud Storage 0.6 API)

com.google.appengine.tools.cloudstorage

Interface RawGcsService

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  public interface RawGcsService

  Low-level ("raw") interface to Google Cloud Storage. This interface need not be used or seen by users of Google Cloud Storage. Instead the higher level API GcsService should be used.

  Methods throw IOException for connection errors etc. that are retryable, and other exceptions for bad requests and similar errors that should not be retried.

  Implementing classes handle authentication through mechanisms not exposed in this interface.

• • Nested Class Summary

    Nested Classes 

    Modifier and Type	Interface and Description
    static class	RawGcsService.ListItemBatch A batch of list items.
    static interface	RawGcsService.RawGcsCreationToken Immutable token that wraps the information a specific implementation of RawGcsService needs to write to an object.

  • Method Summary

    All Methods Instance Methods Abstract Methods 

    Modifier and Type	Method and Description
    RawGcsService.RawGcsCreationToken	beginObjectCreation(GcsFilename filename, GcsFileOptions options, long timeoutMillis)
    void	composeObject(Iterable<String> source, GcsFilename dest, long timeoutMillis) Compose a file from given files.
    Future<RawGcsService.RawGcsCreationToken>	continueObjectCreationAsync(RawGcsService.RawGcsCreationToken token, ByteBuffer chunk, long timeoutMillis) Reads all remaining bytes from chunk and writes them to the object and offset specified by token asynchronously.
    void	copyObject(GcsFilename source, GcsFilename dest, GcsFileOptions fileOptions, long timeoutMillis) Copy source file to dest.
    boolean	deleteObject(GcsFilename filename, long timeoutMillis) Returns true if deleted, false if not found.
    void	finishObjectCreation(RawGcsService.RawGcsCreationToken token, ByteBuffer chunk, long timeoutMillis) Reads all remaining bytes from chunk and writes them to the object and offset specified by token, as the final bytes of the object.
    int	getChunkSizeBytes() Calls to continueObjectCreationAsync(RawGcsCreationToken, ByteBuffer, long) need to pass fixed size chunks.
    int	getMaxWriteSizeByte() Returns the max bytes allowed per putObject/finishObject operations.
    GcsFileMetadata	getObjectMetadata(GcsFilename filename, long timeoutMillis) Returns the meta-data for filename.
    RawGcsService.ListItemBatch	list(String bucket, String prefix, String delimiter, String marker, int maxResults, long timeoutMillis)
    void	putObject(GcsFilename filename, GcsFileOptions options, ByteBuffer content, long timeoutMillis) Create or replace filename with the given content.
    Future<GcsFileMetadata>	readObjectAsync(ByteBuffer dst, GcsFilename filename, long offset, long timeoutMillis) Issues a request to the server to retrieve data to fill the provided buffer.

• • Method Detail

    • getChunkSizeBytes

      int getChunkSizeBytes()

      Calls to continueObjectCreationAsync(RawGcsCreationToken, ByteBuffer, long) need to pass fixed size chunks. This returns the size expected by the implementation.

    • getMaxWriteSizeByte

      int getMaxWriteSizeByte()

      Returns the max bytes allowed per putObject/finishObject operations. Value should always be equal or larger than getChunkSizeBytes().

    • beginObjectCreation

      RawGcsService.RawGcsCreationToken beginObjectCreation(GcsFilename filename,
                                                            GcsFileOptions options,
                                                            long timeoutMillis)
                                                     throws IOException

      Parameters:

      options - null means let Google Cloud Storage use its default

      Throws:

      IOException

    • continueObjectCreationAsync

      Future<RawGcsService.RawGcsCreationToken> continueObjectCreationAsync(RawGcsService.RawGcsCreationToken token,
                                                                            ByteBuffer chunk,
                                                                            long timeoutMillis)

      Reads all remaining bytes from chunk and writes them to the object and offset specified by token asynchronously.

      Returns a future for a new token to be used to continue writing to the object. Does not mutate token.

      The number of bytes remaining in chunk must be a nonzero multiple of getChunkSizeBytes() and may be subject to an upper limit that is implementation-dependent.

      The calling code is responsible for guaranteeing that the byte sequence written to the object remains identical across retries. (This is because the write may have succeeded on the backend even though an exception was thrown by this method, and writing different data on a retry leaves the object in a bad state.)

    • finishObjectCreation

      void finishObjectCreation(RawGcsService.RawGcsCreationToken token,
                                ByteBuffer chunk,
                                long timeoutMillis)
                         throws IOException

      Reads all remaining bytes from chunk and writes them to the object and offset specified by token, as the final bytes of the object. The object will become readable, and further writes will be rejected.

      The number of bytes remaining in chunk may be subject to an upper limit that is implementation-dependent.

      On error, does not consume any bytes from chunk. The write may be retried by making another call with the same token. A whole sequence of writes may be retried by using a previous token (this is useful if the calling code crashes and rolls back to an earlier state). In both cases, the calling code is responsible for guaranteeing that the byte sequence written to the object remains identical across retries. (This is because the write may have succeeded on the backend even though an exception was thrown by this method, and writing different data on a retry leaves the object in a bad state.)

      Throws:

      IOException

    • putObject

      void putObject(GcsFilename filename,
                     GcsFileOptions options,
                     ByteBuffer content,
                     long timeoutMillis)
              throws IOException

      Create or replace filename with the given content.

      Throws:

      IOException

    • readObjectAsync

      Future<GcsFileMetadata> readObjectAsync(ByteBuffer dst,
                                              GcsFilename filename,
                                              long offset,
                                              long timeoutMillis)

      Issues a request to the server to retrieve data to fill the provided buffer. The offset may not be negative.

    • getObjectMetadata

      GcsFileMetadata getObjectMetadata(GcsFilename filename,
                                        long timeoutMillis)
                                 throws IOException

      Returns the meta-data for filename.

      Throws:

      IOException

    • deleteObject

      boolean deleteObject(GcsFilename filename,
                           long timeoutMillis)
                    throws IOException

      Returns true if deleted, false if not found.

      Throws:

      IOException

    • composeObject

      void composeObject(Iterable<String> source,
                         GcsFilename dest,
                         long timeoutMillis)
                  throws IOException

      Compose a file from given files.

      Throws:

      IOException

    • copyObject

      void copyObject(GcsFilename source,
                      GcsFilename dest,
                      GcsFileOptions fileOptions,
                      long timeoutMillis)
               throws IOException

      Copy source file to dest.

      Throws:

      IOException

    • list

      RawGcsService.ListItemBatch list(String bucket,
                                       String prefix,
                                       String delimiter,
                                       String marker,
                                       int maxResults,
                                       long timeoutMillis)
                                throws IOException

      Throws:

      IOException

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