Package com.tnsai.payment.x402

Class InMemoryWallet

java.lang.Object

com.tnsai.payment.x402.InMemoryWallet

All Implemented Interfaces:

Wallet

public final class InMemoryWallet
extends Object
implements Wallet

Test-only Wallet that never touches real cryptography.

What it does

• Holds a fixed 0x... address and a Network.
• signTypedData(EIP712TypedData) returns a deterministic 65-byte (EVM) or 64-byte (SVM) array computed as SHA-256(address || domainSeparator || structHash) padded to the requested length. The output looks like a signature byte-shape-wise but is not verifiable on any chain.

Why it exists

Two reasons:

1. Unit tests of the broker layer need a Wallet they can call without a private key or a network. The deterministic output lets tests assert "the broker passed the right digest" without hard-coding a signature value.
2. The SPI's "what does an implementation look like" reference — anything trickier than this would obscure the shape.

What it is NOT

Not for production. Not for testnet either — its output won't pass any real facilitator's signature check. Any code path that constructs an InMemoryWallet and ships to mainnet has a bug, and the class name is meant to make that bug visible at code review.

Since:

0.10.5 (TNS-449 P2)

Nested Class Summary

Nested classes/interfaces inherited from interface com.tnsai.payment.x402.Wallet

Wallet.Factory

Field Summary

Fields

Modifier and Type	Field	Description
static final String	BACKEND_ID	Backend id used by Wallet.Factory discovery to address this wallet shape.

Method Summary

Modifier and Type	Method	Description
String	address()	Lowercase 0x... hex address.
static InMemoryWallet	forTesting(String address, Network network)	Factory method — naming makes the test-only intent explicit at the call site.
Network	network()	Network the wallet is bound to.
byte[]	signTypedData(EIP712TypedData td)	Produce a signature over the EIP-712 digest implied by td.

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

BACKEND_ID

public static final String BACKEND_ID

Backend id used by Wallet.Factory discovery to address this wallet shape. P2 ships the class but not the factory — callers in tests instantiate via forTesting(String, Network).

See Also:

• Constant Field Values

Method Details

forTesting

public static InMemoryWallet forTesting(String address,
 Network network)

Factory method — naming makes the test-only intent explicit at the call site. Production code that wants a wallet should go through Wallet.Factory.discover() instead.

Parameters:

address - 0x... hex address; case is normalised

network - the network this wallet claims to be on

address

public String address()

Description copied from interface: Wallet

Lowercase 0x... hex address. EVM addresses are 42 chars.

Specified by:

address in interface Wallet

network

public Network network()

Description copied from interface: Wallet

Network the wallet is bound to. Cross-network use is not supported.

Specified by:

network in interface Wallet

signTypedData

public byte[] signTypedData(EIP712TypedData td)

Description copied from interface: Wallet

Produce a signature over the EIP-712 digest implied by td.

Specified by:

signTypedData in interface Wallet

Parameters:

td - prepared domain-separator + struct-hash pair

Returns:

65 bytes for EVM (r || s || v), 64 for SVM