Package com.backblaze.b2.client.contentSources

Interface B2ContentSource

All Known Implementing Classes:

B2ByteArrayContentSource, B2CancellableContentSource, B2FileContentSource

public interface B2ContentSource

Implementations of B2ContentSource provide the length, SHA1, and the bytes that the B2Client should upload. There are common implementations of this class, such as B2FileContentSource and MemoryContentSource.

Method Summary

Modifier and Type	Method	Description
default B2ContentSource	createContentSourceWithRangeOrNull(long start, long length)	If possible, this returns a NEW input stream for just the specified range of the content.
java.io.InputStream	createInputStream()	NOTE: this may be called multiple times as uploads are retried, etc.
long	getContentLength()
java.lang.String	getSha1OrNull()	You are encouraged to implement this.
java.lang.Long	getSrcLastModifiedMillisOrNull()

Method Detail

getContentLength

long getContentLength()
               throws java.io.IOException

Returns:

the number of bytes in the content. the length must be non-negative.

Throws:

java.io.IOException - if there's trouble

getSha1OrNull

java.lang.String getSha1OrNull()
                        throws java.io.IOException

You are encouraged to implement this. If it returns non-null, the B2Client can provide the sha1 before performing the upload. Definitely implement this if you've stored the sha1 separately from the file. That way you can ensure that B2 doesn't take the file if there's trouble reading it from your source. If you return null, B2StorageClient will compute the SHA1 from the bytes in the stream. Note that large files do not have SHA-1s for the entire file. If you provide a SHA-1 for a large file upload, the SDK follows the recommendation of putting your value into the 'large_file_sha1' fileInfo. See "SHA1 Checksums" in https://www.backblaze.com/b2/docs/large_files.html

Returns:

the hex-encoded sha1 for the content or null if it's not known yet.

Throws:

java.io.IOException - if there's trouble

getSrcLastModifiedMillisOrNull

java.lang.Long getSrcLastModifiedMillisOrNull()
                                       throws java.io.IOException

Returns:

the time the source was last modified (in milliseconds since the epoch) or null if there isn't a reasonable value for that.

Throws:

java.io.IOException - if there's trouble

createInputStream

java.io.InputStream createInputStream()
                               throws java.io.IOException,
                                      B2Exception

NOTE: this may be called multiple times as uploads are retried, etc. The content is expected to be identical each time this is called.

Returns:

a new inputStream containing the contents.

Throws:

java.io.IOException - if there's trouble

B2Exception - if there's trouble

createContentSourceWithRangeOrNull

default B2ContentSource createContentSourceWithRangeOrNull(long start,
                                                           long length)
                                                    throws java.io.IOException

If possible, this returns a NEW input stream for just the specified range of the content. If it's not possible (or just not implemented), this returns null. The large file uploading mechanism uses this call to get a stream for each part that will be uploaded separately. If this returns null, the large file uploader will use createInputStream() and read and discard the initial part of the stream to get to the part it needs. This method is optional. However, if your content source will be used for large file uploads, please implement it to make your uploads more efficient. NOTE: this may be called multiple times as uploads are retried, etc. The overall content is expected to be identical each time this is called.

Returns:

a new inputStream containing the specified range of the overall contents.

Throws:

java.io.IOException - if there's trouble