com.klaytn.caver.abi.EventEncoder Maven / Gradle / Ivy
/*
* Modifications copyright 2021 The caver-java Authors
* Copyright 2019 Web3 Labs Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This file is derived from web3j/abi/src/main/java/org/web3j/abi/EventEncoder.java (2021/04/05).
* Modified and improved for the caver-java development.
*/
package com.klaytn.caver.abi;
import com.klaytn.caver.abi.datatypes.Event;
import com.klaytn.caver.abi.datatypes.Type;
import org.web3j.crypto.Hash;
import org.web3j.utils.Numeric;
import java.util.List;
import java.util.stream.Collectors;
/**
* Ethereum filter encoding. Further limited details are available here.
*/
public class EventEncoder {
private EventEncoder() {}
public static String encode(Event event) {
String methodSignature = buildMethodSignature(event.getName(), event.getParameters());
return buildEventSignature(methodSignature);
}
static String buildMethodSignature(
String methodName, List> parameters) {
StringBuilder result = new StringBuilder();
result.append(methodName);
result.append("(");
String params =
parameters.stream().map(p -> Utils.getTypeName(p)).collect(Collectors.joining(","));
result.append(params);
result.append(")");
return result.toString();
}
public static String buildEventSignature(String methodSignature) {
byte[] input = methodSignature.getBytes();
byte[] hash = Hash.sha3(input);
return Numeric.toHexString(hash);
}
}