corda / net.corda.core.transactions

Package net.corda.core.transactions

Base data types for transactions which modify contract state on the distributed ledger.

The core transaction on the ledger is WireTransaction, which is constructed by TransactionBuilder. Once signed a transaction is stored in SignedTransaction which encapsulates WireTransaction. Finally there is a special-case LedgerTransaction which is used by contracts validating transactions, and is built from the wire transaction by resolving all references into their underlying data (i.e. inputs are actual states rather than state references).



abstract class BaseTransaction : NamedByHash

An abstract class defining fields shared by all transaction types in the system.


open class ComponentGroup

A ComponentGroup is used to store the full list of transaction components of the same type in serialised form. Practically, a group per component type of a transaction is required; thus, there will be a group for input states, a group for all attachments (if there are any) etc.


abstract class CoreTransaction : BaseTransaction

A transaction with the minimal amount of information required to compute the unique transaction id, and resolve a FullTransaction. This type of transaction, wrapped in SignedTransaction, gets transferred across the wire and recorded to storage.


data class FilteredComponentGroup : ComponentGroup

A FilteredComponentGroup is used to store the filtered list of transaction components of the same type in serialised form. This is similar to ComponentGroup, but it also includes the corresponding nonce per component.


class FilteredTransaction : TraversableTransaction

Class representing merkleized filtered transaction.


abstract class FullTransaction : BaseTransaction

A transaction with fully resolved components, such as input states.


data class LedgerTransaction : FullTransaction

A LedgerTransaction is derived from a WireTransaction. It is the result of doing the following operations:


data class NotaryChangeLedgerTransaction : FullTransaction, TransactionWithSignatures

A notary change transaction with fully resolved inputs and signatures. In contrast with a regular transaction, signatures are checked against the signers specified by input states' participants fields, so full resolution is needed for signature verification.


data class NotaryChangeWireTransaction : CoreTransaction

A special transaction for changing the notary of a state. It only needs specifying the state(s) as input(s), old and new notaries. Output states can be computed by applying the notary modification to corresponding inputs on the fly.


data class SignedTransaction : TransactionWithSignatures

SignedTransaction wraps a serialized WireTransaction. It contains one or more signatures, each one for a public key (including composite keys) that is mentioned inside a transaction command. SignedTransaction is the top level transaction type and the type most frequently passed around the network and stored. The identity of a transaction is the hash of Merkle root of a WireTransaction, therefore if you are storing data keyed by WT hash be aware that multiple different STs may map to the same key (and they could be different in important ways, like validity!). The signatures on a SignedTransaction might be invalid or missing: the type does not imply validity. A transaction ID should be the hash of the WireTransaction Merkle tree root. Thus adding or removing a signature does not change it.


open class TransactionBuilder

A TransactionBuilder is a transaction class that's mutable (unlike the others which are all immutable). It is intended to be passed around contracts that may edit it by adding new states/commands. Then once the states and commands are right, this class can be used as a holding bucket to gather signatures from multiple parties.


interface TransactionWithSignatures : NamedByHash

An interface for transactions containing signatures, with logic for signature verification


abstract class TraversableTransaction : CoreTransaction

Implemented by WireTransaction and FilteredTransaction. A TraversableTransaction allows you to iterate over the flattened components of the underlying transaction structure, taking into account that some may be missing in the case of this representing a "torn" transaction. Please see the user guide section "Transaction tear-offs" to learn more about this feature.


class WireTransaction : TraversableTransaction

A transaction ready for serialisation, without any signatures attached. A WireTransaction is usually wrapped by a SignedTransaction that carries the signatures over this payload. The identity of the transaction is the Merkle tree root of its components (see MerkleTree).



class ComponentVisibilityException : CordaException

Thrown when checking for visibility of all-components in a group in FilteredTransaction.checkAllComponentsVisible.


class FilteredTransactionVerificationException : CordaException

Thrown when FilteredTransaction.verify fails.


class MissingContractAttachments : Exception

A contract attachment was missing when trying to automatically attach all known contract attachments