add a self manage account method (#49)

* add a self manage account method

* bump version

build.gradle

@@ -13,7 +13,7 @@ plugins {
 }
 
 group = 'io.github.conflux-chain'
-version = '1.2.8'   // SNAPSHOT
+version = '1.2.9'   // SNAPSHOT
 
 repositories {
     jcenter()

src/main/java/conflux/web3j/AMNAccount.java

@@ -0,0 +1,42 @@
+package conflux.web3j;
+
+import conflux.web3j.types.Address;
+import conflux.web3j.types.RawTransaction;
+import conflux.web3j.types.SendTransactionError;
+import conflux.web3j.types.SendTransactionResult;
+import org.web3j.crypto.ECKeyPair;
+
+import java.math.BigInteger;
+
+// Auto manage nonce account
+public class AMNAccount extends Account {
+
+    private BigInteger nonce;
+    public AMNAccount(Cfx cfx, Address address, ECKeyPair ecKeyPair) {
+        super(cfx, address, ecKeyPair);
+        this.nonce = this.getPoolNonce();
+    }
+
+    public void setNonce(BigInteger nonce) {
+        this.nonce = nonce;
+    }
+
+    public BigInteger getNonce() {
+        return this.nonce;
+    }
+
+    private RawTransaction buildRawTransaction(Option option, Address to, String data) {
+        return super.buildRawTransaction(option, to, data, this.nonce);
+    }
+
+    public SendTransactionResult send(String signedTx) throws Exception {
+        SendTransactionResult result = super.send(signedTx);
+        if (result.getRawError() == null
+                || result.getErrorType().equals(SendTransactionError.TxAlreadyExists)
+                || result.getErrorType().equals(SendTransactionError.InvalidNonceAlreadyUsed)) {
+            this.nonce = this.nonce.add(BigInteger.ONE);
+        }
+        return result;
+    }
+
+}

src/main/java/conflux/web3j/Account.java

@@ -46,6 +46,12 @@ private Account(Cfx cfx, Address address) {
 		this.cfx = cfx;
 		this.address = address;
 	}
+
+	public Account(Cfx cfx, Address address, ECKeyPair ecKeyPair) {
+		this.cfx = cfx;
+		this.address = address;
+		this.ecKeyPair = ecKeyPair;
+	}
 
 	public static Account unlock(Cfx cfx, AccountManager am, Address address, String password) throws Exception {
 		return unlock(cfx, am, address, password, Duration.ZERO);
@@ -144,6 +150,10 @@ public String transfer(Option option, Address to, BigInteger value) throws Excep
 	private RawTransaction buildRawTransaction(Option option, Address to, String data) {
 		return option.buildTx(this.cfx, this.address, this.getPoolNonce(), to, data);
 	}
+
+	protected RawTransaction buildRawTransaction(Option option, Address to, String data, BigInteger nonce) {
+		return option.buildTx(this.cfx, this.address, nonce, to, data);
+	}
 
 	public String deploy(String bytecodes, Type<?>... constructorArgs) throws Exception {
 		return this.deploy(new Option(), bytecodes, constructorArgs);