Java SDK
For Java developers who want to work closely with CamDX Digital Signature System, we've got you covered. We've offered a few options and Java SDK is one of them. More languages are coming soon, and they currently are in our release pipeline 
The following steps will get you ready to use our Java SDK.
Installation
Before getting started, make sure you have our repository cloned. If you haven't, please refer to this link to clone the repository
Installing Dependency
After cloning the repository, go to the project directory and into wrapper-service. After that, you can execute lib_bash_install.sh for MacOS and Linux user, or lib_win_install.bat if you're using Windows.
Note
Currently, you can only install the required dependencies via Maven. For those of you who are Gradle users, fear not, Gradle support is coming sooner than expected. Be patient
Setting up environment
Please provide your private key and api server url to consume the API
Usage
CamDX Digital Signature System provide 4 basic functionalities such as
- Sign transaction
- Approve transaction that'd been signed
- Revoke transaction that'd been signed or approved
- Verify transaction signature Details of each functionality will be listed below
Signing Transaction
signRelayFile
Add a digital signature on the current file as InputStream. The file hash will be calculated using SHA-256 hashing algorithm. cid is optional. If you have the file upload to an IPFS, you can also provide the file cid. signers is a list of user addresses that needed to be signed on the transaction. This method return a TransactionReceipt
TransactionReceipt signRelayFile(InputStream inputStream, String cid, List<String> signers) throws IOException, NoSuchAlgorithmException, DisigException;
Note
You can also include your own address in list of signers. However, you can not sign a transaction with empty signers.
signRelayHash
If you prefer to generate file hash, this method is optimized specifically for that purpose. It accepts hex encoded hash of the file, and the rest of the arguments remains the same, and also returns TransactionReceipt
TransactionReceipt signRelayHash(String hashHexEncode, String cid, List<String> signers) throws DisigException, NoSuchAlgorithmException, JsonProcessingException;
signRelayString
Similar to signRelayFile you can also use the content of the transaction as string format for digital signature. Instead of the accepting the file, the first argument of the method accepts a string content of transaction, however, the rest of the method arguments remain unchanged.
TransactionReceipt signRelayString(String inputString, String cid, List<String> signers) throws NoSuchAlgorithmException, DisigException, JsonProcessingException;
Approving a signature
approveRelayFile
After a signature has been added to a file, it is not automatically signed. Your consent is essential for a digital signature. If you want to approve your signature that's been signed by someone else to a file, this method will do the job. It accepts file as InputStream and returns a TransactionReceipt.
TransactionReceipt approveRelayFile(InputStream inputStream) throws IOException, NoSuchAlgorithmException, DisigException;
approveRelayHash
If a signature has been signed on a transaction using hash in hex encoded format, the method is suitable for adding your consent to the signature corelates to the hash that's been signed. This method accept hex encoded hash instead of file InputStream, and returns TransactionReceipt.
TransactionReceipt approveRelayFile(InputStream inputStream) throws IOException, NoSuchAlgorithmException, DisigException;
approveRelayString
Similarly, if the transaction was using content of file as string format, this method can be used to approve your signature on the transaction. This method accepts string instead of file InputStream.
TransactionReceipt approveRelayString(String inputString) throws NoSuchAlgorithmException, DisigException, JsonProcessingException;
Revoking a signature
revokeRelayFile
Accidentally approve a signature or don't want your consent on a signature? Don't worry We got you cover, this method is like the opposite method of approveRelayFile and we think there's no better explain this 
TransactionReceipt revokeRelayFile(InputStream inputStream) throws IOException, NoSuchAlgorithmException, DisigException;
revokeRelayHash
This method is equivalent to the method above but it accepts hash file in hex format.
TransactionReceipt revokeRelayHash(String hashHexEncode) throws DisigException, NoSuchAlgorithmException, JsonProcessingException;
revokeRelayString
This method is equivalent to the method above but it accepts content of file in string format.
TransactionReceipt revokeRelayString(String inputString) throws NoSuchAlgorithmException, DisigException, JsonProcessingException;
Verifying signatures
verifyFile
This method accept a transaction file as inputStream, calculate hash of the file then returns SignerResponse, which includes signatures that have been signed on the file including the status of each signatures.
SignerResponse verifyFile(InputStream inputStream) throws IOException, NoSuchAlgorithmException, DisigException;
verifyHash
If the transaction was signed using hashed calculated by the signer, this method can be used to verify the signature and similar to the method above also returns SignerResponse.
verifyString
On the hand, signer can also uses raw content of transaction as string format to sign the transaction, in this case this method is used for verify it signatures, which returns SignerResponse.
SignerResponse verifyString(String inputString) throws NoSuchAlgorithmException, DisigException, JsonProcessingException;
Dto
Refer to Dto object body such as SignerResponse, ApprovalDto, CertificateResponse, TransactionReceipt
SignerResponse
@Data
public class SignerResponse {
String hash;
String cid;
List<ApproverDto> signers;
}
ApprovalDto
@Data
public class ApproverDto {
String walletAddress;
int status;
String statusString;
CertificateResponse certInfo;
}
CertificateResponse
@Data
public class CertificateResponse {
String serialNumber;
String subject;
String commonName;
String org;
String orgUnit;
String country;
String email;
String pubKey;
Timestamp notBefore;
Timestamp notAfter;
String certificateChain;
}
TransactionReceipt
@Data
public class TransactionReceipt {
private String transactionHash;
private String transactionIndex;
private String blockHash;
private String blockNumber;
private String cumulativeGasUsed;
private String gasUsed;
private String contractAddress;
private String root;
private String status;
private String from;
private String to;
private List<Log> logs;
private String logsBloom;
private String revertReason;
private String type;
private String effectiveGasPrice;
}