Usage

ABI codec

Encoding

Function f = new Function("baz(uint32,bool)"); // canonicalizes and parses any signature automatically
Function f2 = Function.fromJson("{\"name\": \"foo\", \"type\": \"function\", \"inputs\": [ {\"name\": \"complex_nums\", \"type\": \"tuple[]\", \"components\": [ {\"name\": \"real\", \"type\": \"decimal\"}, {\"name\": \"imaginary\", \"type\": \"decimal\"} ]} ]}");
Tuple args = new Tuple(69L, true);
// Two equivalent styles:
ByteBuffer one = f.encodeCall(args);
ByteBuffer two = f.encodeCallWithArgs(69L, true);
System.out.println(Function.formatCall(one.array())); // a multi-line hex representation
System.out.println(f.decodeCall((ByteBuffer) two.flip()).equals(args));

Decoding

Function getUfixedAndString = new Function("gogo((fixed[],int8)[1][][5])", "(ufixed,string)");
Tuple decoded = getUfixedAndString.decodeReturn(
 FastHex.decode(
 "0000000000000000000000000000000000000000000000000000000000000045"
 + "0000000000000000000000000000000000000000000000000000000000000020"
 + "0000000000000000000000000000000000000000000000000000000000000004"
 + "7730307400000000000000000000000000000000000000000000000000000000"
 )
);
 
System.out.println(decoded.equals(new Tuple(new BigDecimal(BigInteger.valueOf(69L), 18), "w00t")));

RLP codec

// for an example class Student
public Student(byte[] rlp) throws DecodeException {
 RLPIterator iter = RLP_STRICT.sequenceIterator(rlp);
 
 this.name = iter.next().asString(UTF_8);
 this.gpa = iter.next().asFloat();
 this.publicKey = iter.next().data();
 this.balance = new BigDecimal(iter.next().asBigInt(), iter.next().asInt());
}
@Override
public Object[] toObjectArray() {
 return new Object[] {
 Strings.decode(name, UTF_8),
 FloatingPoint.toBytes(gpa),
 publicKey,
 balance.unscaledValue().toByteArray(),
 Integers.toBytes(balance.scale())
 };
}
@Override
public byte[] toRLP() {
 return RLPEncoder.encodeSequentially(toObjectArray());
}

Build

implementation 'com.esaulpaugh:headlong:1.4.8-SNAPSHOT'

<dependency>
 <groupId>com.esaulpaugh</groupId>
 <artifactId>headlong</artifactId>
 <version>1.4.8-SNAPSHOT</version>
</dependency>