Introducing the CreateHtlcOperation & supporting classes

- HtlcHashType class enumerates all supported HTLC hash functions.
- The HtlcHash class is used to represent all possible HTLC hash results.
- The CreateHtlcOperation class itself is used to represent the operation that creates an HTLC
- A simple test class was introduced in order to test hash functions and subsequently also test the HTLC operation serialization

graphenej/src/main/java/cy/agorise/graphenej/HtlcHash.java

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+package cy.agorise.graphenej;
+
+import com.google.common.primitives.Bytes;
+
+import cy.agorise.graphenej.interfaces.ByteSerializable;
+
+/**
+ * Class used to represent a HTLC hash.
+ */
+public class HtlcHash implements ByteSerializable {
+    private HtlcHashType hashType;
+    private byte[] hash;
+
+    public HtlcHash(HtlcHashType hashType, byte[] hash) {
+        this.hashType = hashType;
+        this.hash = hash;
+    }
+
+    @Override
+    public byte[] toBytes() {
+        byte[] hashTypeBytes = new byte[] { Util.revertInteger(hashType.ordinal())[3] };
+        return Bytes.concat(hashTypeBytes, hash);
+    }
+}

graphenej/src/main/java/cy/agorise/graphenej/HtlcHashType.java

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+package cy.agorise.graphenej;
+
+/**
+ * Used to enumerate the possible hash algorithms used in HTLCs.
+ * @see <a href="https://github.com/bitshares/bitshares-core/blob/623aea265f2711adade982fc3248e6528dc8ac51/libraries/chain/include/graphene/chain/protocol/htlc.hpp">htlc.hpp</a>
+ */
+public enum HtlcHashType {
+    RIPEMD160,
+    SHA1,
+    SHA256
+}

graphenej/src/main/java/cy/agorise/graphenej/operations/CreateHtlcOperation.java

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+package cy.agorise.graphenej.operations;
+
+import com.google.common.primitives.Bytes;
+
+import cy.agorise.graphenej.AssetAmount;
+import cy.agorise.graphenej.BaseOperation;
+import cy.agorise.graphenej.HtlcHash;
+import cy.agorise.graphenej.OperationType;
+import cy.agorise.graphenej.UserAccount;
+import cy.agorise.graphenej.Util;
+
+public class CreateHtlcOperation extends BaseOperation {
+    private AssetAmount fee;
+    private UserAccount from;
+    private UserAccount to;
+    private AssetAmount amount;
+    private HtlcHash preimageHash;
+    private short preimageSize;
+    private int claimPeriodSeconds;
+
+    /**
+     * Public constructor
+     *
+     * @param fee The operation fee.
+     * @param from The source account.
+     * @param to The destination account.
+     * @param amount The amount to be traded.
+     * @param hash The pre-image hash.
+     * @param preimageSize The pre-image size.
+     * @param claimPeriodSeconds The claim period, in seconds.
+     */
+    public CreateHtlcOperation(AssetAmount fee, UserAccount from, UserAccount to, AssetAmount amount, HtlcHash hash, short preimageSize, int claimPeriodSeconds) {
+        super(OperationType.HTLC_CREATE_OPERATION);
+        this.fee = fee;
+        this.from = from;
+        this.to = to;
+        this.amount = amount;
+        this.preimageHash = hash;
+        this.preimageSize = preimageSize;
+        this.claimPeriodSeconds = claimPeriodSeconds;
+    }
+
+    @Override
+    public void setFee(AssetAmount newFee){
+        this.fee = newFee;
+    }
+
+    public AssetAmount getFee() {
+        return fee;
+    }
+
+    public UserAccount getFrom() {
+        return from;
+    }
+
+    public void setFrom(UserAccount from) {
+        this.from = from;
+    }
+
+    public UserAccount getTo() {
+        return to;
+    }
+
+    public void setTo(UserAccount to) {
+        this.to = to;
+    }
+
+    public AssetAmount getAmount() {
+        return amount;
+    }
+
+    public void setAmount(AssetAmount amount) {
+        this.amount = amount;
+    }
+
+    public HtlcHash getPreimageHash() {
+        return preimageHash;
+    }
+
+    public void setPreimageHash(HtlcHash preimageHash) {
+        this.preimageHash = preimageHash;
+    }
+
+    public short getPreimageSize() {
+        return preimageSize;
+    }
+
+    public void setPreimageSize(short preimageSize) {
+        this.preimageSize = preimageSize;
+    }
+
+    public int getClaimPeriodSeconds() {
+        return claimPeriodSeconds;
+    }
+
+    public void setClaimPeriodSeconds(int claimPeriodSeconds) {
+        this.claimPeriodSeconds = claimPeriodSeconds;
+    }
+
+    @Override
+    public byte[] toBytes() {
+        byte[] feeBytes = fee.toBytes();
+        byte[] fromBytes = from.toBytes();
+        byte[] toBytes = to.toBytes();
+        byte[] amountBytes = amount.toBytes();
+        byte[] htlcHashBytes = preimageHash.toBytes();
+        byte[] preimageSizeBytes = Util.revertShort(preimageSize);
+        byte[] claimPeriodBytes = Util.revertInteger(claimPeriodSeconds);
+        byte[] extensionsBytes = extensions.toBytes();
+        return Bytes.concat(feeBytes, fromBytes, toBytes, amountBytes, htlcHashBytes, preimageSizeBytes, claimPeriodBytes, extensionsBytes);
+    }
+
+    @Override
+    public String toJsonString() {
+        return null;
+    }
+}

graphenej/src/test/java/cy/agorise/graphenej/operations/CreateHtlcOperationTest.java

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+package cy.agorise.graphenej.operations;
+
+import com.google.common.primitives.UnsignedLong;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.security.NoSuchAlgorithmException;
+
+import cy.agorise.graphenej.Asset;
+import cy.agorise.graphenej.AssetAmount;
+import cy.agorise.graphenej.HtlcHash;
+import cy.agorise.graphenej.HtlcHashType;
+import cy.agorise.graphenej.UserAccount;
+import cy.agorise.graphenej.Util;
+
+public class CreateHtlcOperationTest {
+    private final String SERIALIZED_OP = "f68585abf4dce7c8045701310000000000000000007b7c80241100000000000000a06e327ea7388c18e4740e350ed4e60f2e04fc41c80078000000000001";
+    private final String PREIMAGE_HEX = "666f6f626172";
+    private final String HASH_RIPEMD160 = "a06e327ea7388c18e4740e350ed4e60f2e04fc41";
+    private final String HASH_SHA1 = "8843d7f92416211de9ebb963ff4ce28125932878";
+    private final String HASH_SHA256 = "c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2";
+
+    private final Asset CORE = new Asset("1.3.0");
+
+    @Test
+    public void testRipemd160(){
+        try {
+            byte[] hashRipemd160 = Util.htlcHash(Util.hexToBytes(PREIMAGE_HEX), HtlcHashType.RIPEMD160);
+            String hexHash = Util.bytesToHex(hashRipemd160);
+            Assert.assertEquals(HASH_RIPEMD160, hexHash);
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void testSha1(){
+        try {
+            byte[] hashSha1 = Util.htlcHash(Util.hexToBytes(PREIMAGE_HEX), HtlcHashType.SHA1);
+            String hexHash = Util.bytesToHex(hashSha1);
+            Assert.assertEquals(HASH_SHA1, hexHash);
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void testSha256(){
+        try {
+            byte[] hashSha256 = Util.htlcHash(Util.hexToBytes(PREIMAGE_HEX), HtlcHashType.SHA256);
+            String hexHash = Util.bytesToHex(hashSha256);
+            Assert.assertEquals(HASH_SHA256, hexHash);
+        } catch (NoSuchAlgorithmException e) {
+            e.printStackTrace();
+        }
+    }
+
+    //TODO: Implement operation test
+    public void testOperationSerialization() throws NoSuchAlgorithmException {
+        UserAccount from = new UserAccount("1.2.123");
+        UserAccount to = new UserAccount("1.2.124");
+        AssetAmount fee = new AssetAmount(UnsignedLong.valueOf(0), CORE);
+        AssetAmount amount = new AssetAmount(UnsignedLong.valueOf(1123456), CORE);
+        byte[] hashBytes = Util.htlcHash("foobar".getBytes(), HtlcHashType.RIPEMD160);
+        HtlcHash preimageHash = new HtlcHash(HtlcHashType.RIPEMD160, hashBytes);
+        CreateHtlcOperation operation = new CreateHtlcOperation(fee, from, to, amount, preimageHash, (short) 200, 120);
+    }
+}