org.icij.extract.document

Interface Identifier

All Known Implementing Classes:

AbstractIdentifier, DigestIdentifier, PathDigestIdentifier, PathIdentifier

public interface Identifier

An Identifier holds logic for generating both unique identifiers for documents as well as digest hashes of the the underlying file data.

Method Summary

Modifier and Type	Method and Description
String	generate(TikaDocument tikaDocument) Generate an identifier for a root tikaDocument.
String	generateForEmbed(EmbeddedTikaDocument document) Generate an identifier for an embedded document.
String	hash(TikaDocument tikaDocument) Generate or retrieve (from metadata) a hash digest of the tikaDocument's underlying file data.
String	retrieveHash(org.apache.tika.metadata.Metadata metadata) Retrieve a hash digest of the document's underlying file data.

Method Detail

generate

String generate(TikaDocument tikaDocument)
         throws Exception

Generate an identifier for a root tikaDocument.

Parameters:

tikaDocument - the tikaDocument to generate an identifier for

Returns:

A unique identifier, for example a fixed-length hash.

Throws:

Exception - if there's an exception generating the ID

generateForEmbed

String generateForEmbed(EmbeddedTikaDocument document)
                 throws Exception

Generate an identifier for an embedded document.

Parameters:

document - the embedded document to generate an ID for

Returns:

A unique identifier for the embedded document.

Throws:

Exception - if there's an error generating the ID

hash

String hash(TikaDocument tikaDocument)
     throws Exception

Generate or retrieve (from metadata) a hash digest of the tikaDocument's underlying file data. Even if the generate(TikaDocument) methods of the implementation generate hash digests, those are semantically different as they represent a hash of the tikaDocument, rather than the file. The former might comprise the the relationship of the tikaDocument with its parent, or its position in the path hierarchy, whereas the latter must not.

Parameters:

tikaDocument - the tikaDocument for which to return a file hash digest

Returns:

the hash

Throws:

Exception - if there's an error generating the hash

retrieveHash

String retrieveHash(org.apache.tika.metadata.Metadata metadata)

Retrieve a hash digest of the document's underlying file data.

Parameters:

metadata - the document's metadata

Returns:

the hash