Adding template for deploying smart contracts on Ethereum

ethereumj/pom.xml

@@ -48,6 +48,13 @@
             <version>1.5.0-RELEASE</version>
         </dependency>
 
+        <!-- Web3j -->
+        <dependency>
+            <groupId>org.web3j</groupId>
+            <artifactId>core</artifactId>
+            <version>3.3.1</version>
+        </dependency>
+
         <!-- JSTL/JSP -->
         <dependency>
             <groupId>javax.servlet</groupId>

ethereumj/src/main/java/com/baeldung/web3j/Template.java

@@ -0,0 +1,41 @@
+package com.baeldung.web3j;
+
+import com.baeldung.web3j.contracts.Greeting;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.web3j.crypto.Credentials;
+import org.web3j.crypto.WalletUtils;
+import org.web3j.protocol.Web3j;
+import org.web3j.protocol.core.methods.response.TransactionReceipt;
+import org.web3j.protocol.http.HttpService;
+import org.web3j.tx.Contract;
+import org.web3j.tx.ManagedTransaction;
+
+public class Template {
+
+    private Logger l = LoggerFactory.getLogger(Template.class);
+
+    private void deployContract() throws Exception{
+
+        Web3j web3j = Web3j.build(new HttpService("https://rinkeby.infura.io/<your_token>"));
+
+        Credentials credentials =
+            WalletUtils.loadCredentials(
+               "<password>",
+               "/path/to/<walletfile>");
+
+        Greeting contract = Greeting.deploy(
+            web3j, credentials,
+            ManagedTransaction.GAS_PRICE, Contract.GAS_LIMIT,
+            "Hello blockchain world!").send();
+
+        String contractAddress = contract.getContractAddress();
+        l.debug("Smart contract deployed to address "+ contractAddress);
+
+        l.debug("Value stored in remote smart contract: "+ contract.greet().send());
+
+        TransactionReceipt transactionReceipt = contract.setGreeting("Well hello again").send();
+
+        l.debug("New value stored in remote smart contract: "+ contract.greet().send());
+    }
+}

ethereumj/src/main/java/com/baeldung/web3j/contracts/Greeting.java

@@ -0,0 +1,71 @@
+package com.baeldung.web3j.contracts;
+
+import java.math.BigInteger;
+import java.util.Arrays;
+import java.util.Collections;
+import org.web3j.abi.FunctionEncoder;
+import org.web3j.abi.TypeReference;
+import org.web3j.abi.datatypes.Function;
+import org.web3j.abi.datatypes.Type;
+import org.web3j.abi.datatypes.Utf8String;
+import org.web3j.crypto.Credentials;
+import org.web3j.protocol.Web3j;
+import org.web3j.protocol.core.RemoteCall;
+import org.web3j.protocol.core.methods.response.TransactionReceipt;
+import org.web3j.tx.Contract;
+import org.web3j.tx.TransactionManager;
+
+/**
+ * <p>Auto generated code.
+ * <p><strong>Do not modify!</strong>
+ * <p>Please use the <a href="https://docs.web3j.io/command_line.html">web3j command line tools</a>,
+ * or the org.web3j.codegen.SolidityFunctionWrapperGenerator in the
+ * <a href="https://github.com/web3j/web3j/tree/master/codegen">codegen module</a> to update.
+ *
+ * <p>Generated with web3j version 3.3.1.
+ */
+public class Greeting extends Contract {
+    private static final String BINARY = "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";
+
+    protected Greeting(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
+        super(BINARY, contractAddress, web3j, credentials, gasPrice, gasLimit);
+    }
+
+    protected Greeting(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
+        super(BINARY, contractAddress, web3j, transactionManager, gasPrice, gasLimit);
+    }
+
+    public RemoteCall<TransactionReceipt> setGreeting(String _message) {
+        final Function function = new Function(
+                "setGreeting",
+                Arrays.<Type>asList(new org.web3j.abi.datatypes.Utf8String(_message)),
+                Collections.<TypeReference<?>>emptyList());
+        return executeRemoteCallTransaction(function);
+    }
+
+    public RemoteCall<String> greet() {
+        final Function function = new Function("greet",
+                Arrays.<Type>asList(),
+                Arrays.<TypeReference<?>>asList(new TypeReference<Utf8String>() {}));
+        return executeRemoteCallSingleValueReturn(function, String.class);
+    }
+
+    public static RemoteCall<Greeting> deploy(Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit, String _message) {
+        String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(new org.web3j.abi.datatypes.Utf8String(_message)));
+        return deployRemoteCall(Greeting.class, web3j, credentials, gasPrice, gasLimit, BINARY, encodedConstructor);
+    }
+
+    public static RemoteCall<Greeting> deploy(Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit, String _message) {
+        String encodedConstructor = FunctionEncoder.encodeConstructor(Arrays.<Type>asList(new org.web3j.abi.datatypes.Utf8String(_message)));
+        return deployRemoteCall(Greeting.class, web3j, transactionManager, gasPrice, gasLimit, BINARY, encodedConstructor);
+    }
+
+    public static Greeting load(String contractAddress, Web3j web3j, Credentials credentials, BigInteger gasPrice, BigInteger gasLimit) {
+        return new Greeting(contractAddress, web3j, credentials, gasPrice, gasLimit);
+    }
+
+    public static Greeting load(String contractAddress, Web3j web3j, TransactionManager transactionManager, BigInteger gasPrice, BigInteger gasLimit) {
+        return new Greeting(contractAddress, web3j, transactionManager, gasPrice, gasLimit);
+    }
+}
+

ethereumj/src/main/resources/solidity/Greeting.sol

@@ -0,0 +1,19 @@
+pragma solidity ^0.4.0;
+
+contract Greeting {
+    address creator;
+    string message;
+
+    function Greeting(string _message) {
+        message = _message;
+        creator = msg.sender;
+    }
+
+    function greet() constant returns (string) {
+        return message;
+    }
+
+    function setGreeting(string _message) {
+        message = _message;
+    }
+}

ethereumj/src/main/resources/solidity/build/Greeting.abi

@@ -0,0 +1 @@
+[{"constant":false,"inputs":[{"name":"_message","type":"string"}],"name":"setGreeting","outputs":[],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":true,"inputs":[],"name":"greet","outputs":[{"name":"","type":"string"}],"payable":false,"stateMutability":"view","type":"function"},{"inputs":[{"name":"_message","type":"string"}],"payable":false,"stateMutability":"nonpayable","type":"constructor"}]

ethereumj/src/main/resources/solidity/build/Greeting.bin

@@ -0,0 +1 @@
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