Package org.pgpainless.decryption_verification.cleartext_signatures

Interface MultiPassStrategy

All Known Implementing Classes:

InMemoryMultiPassStrategy, WriteToFileMultiPassStrategy

public interface MultiPassStrategy

Since the CleartextSignatureProcessor needs to read the whole data twice in order to verify signatures, a strategy for how to cache the read data is required. Otherwise, large data kept in memory could cause OutOfMemoryErrors or other issues. This is an Interface that describes a strategy to deal with the fact that detached signatures require multiple passes to do verification. This interface can be used to write the signed data stream out via getMessageOutputStream() and later get access to the data again via getMessageInputStream(). Thereby the detail where the data is being stored (memory, file, etc.) can be abstracted away.

Method Summary

Modifier and Type	Method	Description
InputStream	getMessageInputStream()	Provide an InputStream which contains the data that was previously written away in getMessageOutputStream().
OutputStream	getMessageOutputStream()	Provide an OutputStream into which the signed data can be read into.
static InMemoryMultiPassStrategy	keepMessageInMemory()	Read the message content into memory.
static MultiPassStrategy	writeMessageToFile(File file)	Write the message content out to a file and re-read it to verify signatures.

Method Detail

getMessageOutputStream

OutputStream getMessageOutputStream()
                             throws IOException

Provide an OutputStream into which the signed data can be read into.

Returns:

output stream

Throws:

IOException - io error

getMessageInputStream

InputStream getMessageInputStream()
                           throws IOException

Provide an InputStream which contains the data that was previously written away in getMessageOutputStream(). As there may be multiple signatures that need to be processed, each call of this method MUST return a new InputStream.

Returns:

input stream

Throws:

IOException - io error

writeMessageToFile

static MultiPassStrategy writeMessageToFile(File file)

Write the message content out to a file and re-read it to verify signatures. This strategy is best suited for larger messages (e.g. plaintext signed files) which might not fit into memory. After the message has been processed completely, the messages content are available at the provided file.

Parameters:

file - target file

Returns:

strategy

keepMessageInMemory

static InMemoryMultiPassStrategy keepMessageInMemory()

Read the message content into memory. This strategy is best suited for small messages which fit into memory. After the message has been processed completely, the message content can be accessed by calling ByteArrayOutputStream.toByteArray() on getMessageOutputStream().

Returns:

strategy