/* * Copyright 2011 Google Inc. * Copyright 2014 Andreas Schildbach * * 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. */ package org.bitcoinj.core; import org.bitcoinj.core.TransactionConfidence.ConfidenceType; import org.bitcoinj.crypto.TransactionSignature; import org.bitcoinj.script.Script; import org.bitcoinj.script.ScriptBuilder; import org.bitcoinj.script.ScriptOpCodes; import org.bitcoinj.signers.TransactionSigner; import org.bitcoinj.utils.ExchangeRate; import org.bitcoinj.wallet.Wallet; import org.bitcoinj.wallet.WalletTransaction.Pool; import com.google.common.collect.ImmutableMap; import com.google.common.primitives.Ints; import com.google.common.primitives.Longs; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.spongycastle.crypto.params.KeyParameter; import javax.annotation.Nullable; import java.io.*; import java.util.*; import static org.bitcoinj.core.Utils.*; import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkState; import java.math.BigInteger; /** * <p>A transaction represents the movement of coins from some addresses to some other addresses. It can also represent * the minting of new coins. A Transaction object corresponds to the equivalent in the Bitcoin C++ implementation.</p> * * <p>Transactions are the fundamental atoms of Bitcoin and have many powerful features. Read * <a href="https://bitcoinj.github.io/working-with-transactions">"Working with transactions"</a> in the * documentation to learn more about how to use this class.</p> * * <p>All Bitcoin transactions are at risk of being reversed, though the risk is much less than with traditional payment * systems. Transactions have <i>confidence levels</i>, which help you decide whether to trust a transaction or not. * Whether to trust a transaction is something that needs to be decided on a case by case basis - a rule that makes * sense for selling MP3s might not make sense for selling cars, or accepting payments from a family member. If you * are building a wallet, how to present confidence to your users is something to consider carefully.</p> * * <p>Instances of this class are not safe for use by multiple threads.</p> */ public class Transaction extends ChildMessage { /** * A comparator that can be used to sort transactions by their updateTime field. The ordering goes from most recent * into the past. */ public static final Comparator<Transaction> SORT_TX_BY_UPDATE_TIME = new Comparator<Transaction>() { @Override public int compare(final Transaction tx1, final Transaction tx2) { final long time1 = tx1.getUpdateTime().getTime(); final long time2 = tx2.getUpdateTime().getTime(); final int updateTimeComparison = -(Longs.compare(time1, time2)); //If time1==time2, compare by tx hash to make comparator consistent with equals return updateTimeComparison != 0 ? updateTimeComparison : tx1.getHash().compareTo(tx2.getHash()); } }; /** A comparator that can be used to sort transactions by their chain height. */ public static final Comparator<Transaction> SORT_TX_BY_HEIGHT = new Comparator<Transaction>() { @Override public int compare(final Transaction tx1, final Transaction tx2) { final int height1 = tx1.getConfidence().getAppearedAtChainHeight(); final int height2 = tx2.getConfidence().getAppearedAtChainHeight(); final int heightComparison = -(Ints.compare(height1, height2)); //If height1==height2, compare by tx hash to make comparator consistent with equals return heightComparison != 0 ? heightComparison : tx1.getHash().compareTo(tx2.getHash()); } }; private static final Logger log = LoggerFactory.getLogger(Transaction.class); /** Threshold for lockTime: below this value it is interpreted as block number, otherwise as timestamp. **/ public static final int LOCKTIME_THRESHOLD = 500000000; // Tue Nov 5 00:53:20 1985 UTC /** Same but as a BigInteger for CHECKLOCKTIMEVERIFY */ public static final BigInteger LOCKTIME_THRESHOLD_BIG = BigInteger.valueOf(LOCKTIME_THRESHOLD); /** How many bytes a transaction can be before it won't be relayed anymore. Currently 100kb. */ public static final int MAX_STANDARD_TX_SIZE = 100000; /** * If feePerKb is lower than this, Bitcoin Core will treat it as if there were no fee. */ public static final Coin REFERENCE_DEFAULT_MIN_TX_FEE = Coin.valueOf(5000); // 0.05 mBTC /** * If using this feePerKb, transactions will get confirmed within the next couple of blocks. * This should be adjusted from time to time. Last adjustment: March 2016. */ public static final Coin DEFAULT_TX_FEE = Coin.valueOf(50000); // 0.5 mBTC /** * Any standard (ie pay-to-address) output smaller than this value (in satoshis) will most likely be rejected by the network. * This is calculated by assuming a standard output will be 34 bytes, and then using the formula used in * {@link TransactionOutput#getMinNonDustValue(Coin)}. */ public static final Coin MIN_NONDUST_OUTPUT = Coin.valueOf(2730); // satoshis // These are bitcoin serialized. private long version; private ArrayList<TransactionInput> inputs; private ArrayList<TransactionOutput> outputs; private long lockTime; // This is either the time the transaction was broadcast as measured from the local clock, or the time from the // block in which it was included. Note that this can be changed by re-orgs so the wallet may update this field. // Old serialized transactions don't have this field, thus null is valid. It is used for returning an ordered // list of transactions from a wallet, which is helpful for presenting to users. private Date updatedAt; // This is an in memory helper only. private Sha256Hash hash; // Data about how confirmed this tx is. Serialized, may be null. @Nullable private TransactionConfidence confidence; // Records a map of which blocks the transaction has appeared in (keys) to an index within that block (values). // The "index" is not a real index, instead the values are only meaningful relative to each other. For example, // consider two transactions that appear in the same block, t1 and t2, where t2 spends an output of t1. Both // will have the same block hash as a key in their appearsInHashes, but the counter would be 1 and 2 respectively // regardless of where they actually appeared in the block. // // If this transaction is not stored in the wallet, appearsInHashes is null. private Map<Sha256Hash, Integer> appearsInHashes; // Transactions can be encoded in a way that will use more bytes than is optimal // (due to VarInts having multiple encodings) // MAX_BLOCK_SIZE must be compared to the optimal encoding, not the actual encoding, so when parsing, we keep track // of the size of the ideal encoding in addition to the actual message size (which Message needs) so that Blocks // can properly keep track of optimal encoded size private int optimalEncodingMessageSize; /** * This enum describes the underlying reason the transaction was created. It's useful for rendering wallet GUIs * more appropriately. */ public enum Purpose { /** Used when the purpose of a transaction is genuinely unknown. */ UNKNOWN, /** Transaction created to satisfy a user payment request. */ USER_PAYMENT, /** Transaction automatically created and broadcast in order to reallocate money from old to new keys. */ KEY_ROTATION, /** Transaction that uses up pledges to an assurance contract */ ASSURANCE_CONTRACT_CLAIM, /** Transaction that makes a pledge to an assurance contract. */ ASSURANCE_CONTRACT_PLEDGE, /** Send-to-self transaction that exists just to create an output of the right size we can pledge. */ ASSURANCE_CONTRACT_STUB, /** Raise fee, e.g. child-pays-for-parent. */ RAISE_FEE, // In future: de/refragmentation, privacy boosting/mixing, etc. // When adding a value, it also needs to be added to wallet.proto, WalletProtobufSerialize.makeTxProto() // and WalletProtobufSerializer.readTransaction()! } private Purpose purpose = Purpose.UNKNOWN; /** * This field can be used by applications to record the exchange rate that was valid when the transaction happened. * It's optional. */ @Nullable private ExchangeRate exchangeRate; /** * This field can be used to record the memo of the payment request that initiated the transaction. It's optional. */ @Nullable private String memo; public Transaction(NetworkParameters params) { super(params); version = 1; inputs = new ArrayList<TransactionInput>(); outputs = new ArrayList<TransactionOutput>(); // We don't initialize appearsIn deliberately as it's only useful for transactions stored in the wallet. length = 8; // 8 for std fields } /** * Creates a transaction from the given serialized bytes, eg, from a block or a tx network message. */ public Transaction(NetworkParameters params, byte[] payloadBytes) throws ProtocolException { super(params, payloadBytes, 0); } /** * Creates a transaction by reading payload starting from offset bytes in. Length of a transaction is fixed. */ public Transaction(NetworkParameters params, byte[] payload, int offset) throws ProtocolException { super(params, payload, offset); // inputs/outputs will be created in parse() } /** * Creates a transaction by reading payload starting from offset bytes in. Length of a transaction is fixed. * @param params NetworkParameters object. * @param payload Bitcoin protocol formatted byte array containing message content. * @param offset The location of the first payload byte within the array. * @param parseRetain Whether to retain the backing byte array for quick reserialization. * If true and the backing byte array is invalidated due to modification of a field then * the cached bytes may be repopulated and retained if the message is serialized again in the future. * @param length The length of message if known. Usually this is provided when deserializing of the wire * as the length will be provided as part of the header. If unknown then set to Message.UNKNOWN_LENGTH * @throws ProtocolException */ public Transaction(NetworkParameters params, byte[] payload, int offset, @Nullable Message parent, MessageSerializer setSerializer, int length) throws ProtocolException { super(params, payload, offset, parent, setSerializer, length); } /** * Creates a transaction by reading payload. Length of a transaction is fixed. */ public Transaction(NetworkParameters params, byte[] payload, @Nullable Message parent, MessageSerializer setSerializer, int length) throws ProtocolException { super(params, payload, 0, parent, setSerializer, length); } /** * Returns the transaction hash as you see them in the block explorer. */ @Override public Sha256Hash getHash() { if (hash == null) { hash = Sha256Hash.wrapReversed(Sha256Hash.hashTwice(unsafeBitcoinSerialize())); } return hash; } /** * Used by BitcoinSerializer. The serializer has to calculate a hash for checksumming so to * avoid wasting the considerable effort a set method is provided so the serializer can set it. * * No verification is performed on this hash. */ void setHash(Sha256Hash hash) { this.hash = hash; } public String getHashAsString() { return getHash().toString(); } /** * Gets the sum of the inputs, regardless of who owns them. */ public Coin getInputSum() { Coin inputTotal = Coin.ZERO; for (TransactionInput input: inputs) { Coin inputValue = input.getValue(); if (inputValue != null) { inputTotal = inputTotal.add(inputValue); } } return inputTotal; } /** * Calculates the sum of the outputs that are sending coins to a key in the wallet. */ public Coin getValueSentToMe(TransactionBag transactionBag) { // This is tested in WalletTest. Coin v = Coin.ZERO; for (TransactionOutput o : outputs) { if (!o.isMineOrWatched(transactionBag)) continue; v = v.add(o.getValue()); } return v; } /** * Returns a map of block [hashes] which contain the transaction mapped to relativity counters, or null if this * transaction doesn't have that data because it's not stored in the wallet or because it has never appeared in a * block. */ @Nullable public Map<Sha256Hash, Integer> getAppearsInHashes() { return appearsInHashes != null ? ImmutableMap.copyOf(appearsInHashes) : null; } /** * Convenience wrapper around getConfidence().getConfidenceType() * @return true if this transaction hasn't been seen in any block yet. */ public boolean isPending() { return getConfidence().getConfidenceType() == TransactionConfidence.ConfidenceType.PENDING; } /** * <p>Puts the given block in the internal set of blocks in which this transaction appears. This is * used by the wallet to ensure transactions that appear on side chains are recorded properly even though the * block stores do not save the transaction data at all.</p> * * <p>If there is a re-org this will be called once for each block that was previously seen, to update which block * is the best chain. The best chain block is guaranteed to be called last. So this must be idempotent.</p> * * <p>Sets updatedAt to be the earliest valid block time where this tx was seen.</p> * * @param block The {@link StoredBlock} in which the transaction has appeared. * @param bestChain whether to set the updatedAt timestamp from the block header (only if not already set) * @param relativityOffset A number that disambiguates the order of transactions within a block. */ public void setBlockAppearance(StoredBlock block, boolean bestChain, int relativityOffset) { long blockTime = block.getHeader().getTimeSeconds() * 1000; if (bestChain && (updatedAt == null || updatedAt.getTime() == 0 || updatedAt.getTime() > blockTime)) { updatedAt = new Date(blockTime); } addBlockAppearance(block.getHeader().getHash(), relativityOffset); if (bestChain) { TransactionConfidence transactionConfidence = getConfidence(); // This sets type to BUILDING and depth to one. transactionConfidence.setAppearedAtChainHeight(block.getHeight()); } } public void addBlockAppearance(final Sha256Hash blockHash, int relativityOffset) { if (appearsInHashes == null) { // TODO: This could be a lot more memory efficient as we'll typically only store one element. appearsInHashes = new TreeMap<Sha256Hash, Integer>(); } appearsInHashes.put(blockHash, relativityOffset); } /** * Calculates the sum of the inputs that are spending coins with keys in the wallet. This requires the * transactions sending coins to those keys to be in the wallet. This method will not attempt to download the * blocks containing the input transactions if the key is in the wallet but the transactions are not. * * @return sum of the inputs that are spending coins with keys in the wallet */ public Coin getValueSentFromMe(TransactionBag wallet) throws ScriptException { // This is tested in WalletTest. Coin v = Coin.ZERO; for (TransactionInput input : inputs) { // This input is taking value from a transaction in our wallet. To discover the value, // we must find the connected transaction. TransactionOutput connected = input.getConnectedOutput(wallet.getTransactionPool(Pool.UNSPENT)); if (connected == null) connected = input.getConnectedOutput(wallet.getTransactionPool(Pool.SPENT)); if (connected == null) connected = input.getConnectedOutput(wallet.getTransactionPool(Pool.PENDING)); if (connected == null) continue; // The connected output may be the change to the sender of a previous input sent to this wallet. In this // case we ignore it. if (!connected.isMineOrWatched(wallet)) continue; v = v.add(connected.getValue()); } return v; } /** * Gets the sum of the outputs of the transaction. If the outputs are less than the inputs, it does not count the fee. * @return the sum of the outputs regardless of who owns them. */ public Coin getOutputSum() { Coin totalOut = Coin.ZERO; for (TransactionOutput output: outputs) { totalOut = totalOut.add(output.getValue()); } return totalOut; } @Nullable private Coin cachedValue; @Nullable private TransactionBag cachedForBag; /** * Returns the difference of {@link Transaction#getValueSentToMe(TransactionBag)} and {@link Transaction#getValueSentFromMe(TransactionBag)}. */ public Coin getValue(TransactionBag wallet) throws ScriptException { // FIXME: TEMP PERF HACK FOR ANDROID - this crap can go away once we have a real payments API. boolean isAndroid = Utils.isAndroidRuntime(); if (isAndroid && cachedValue != null && cachedForBag == wallet) return cachedValue; Coin result = getValueSentToMe(wallet).subtract(getValueSentFromMe(wallet)); if (isAndroid) { cachedValue = result; cachedForBag = wallet; } return result; } /** * The transaction fee is the difference of the value of all inputs and the value of all outputs. Currently, the fee * can only be determined for transactions created by us. * * @return fee, or null if it cannot be determined */ public Coin getFee() { Coin fee = Coin.ZERO; for (TransactionInput input : inputs) { if (input.getValue() == null) return null; fee = fee.add(input.getValue()); } for (TransactionOutput output : outputs) { fee = fee.subtract(output.getValue()); } return fee; } /** * Returns true if any of the outputs is marked as spent. */ public boolean isAnyOutputSpent() { for (TransactionOutput output : outputs) { if (!output.isAvailableForSpending()) return true; } return false; } /** * Returns false if this transaction has at least one output that is owned by the given wallet and unspent, true * otherwise. */ public boolean isEveryOwnedOutputSpent(TransactionBag transactionBag) { for (TransactionOutput output : outputs) { if (output.isAvailableForSpending() && output.isMineOrWatched(transactionBag)) return false; } return true; } /** * Returns the earliest time at which the transaction was seen (broadcast or included into the chain), * or the epoch if that information isn't available. */ public Date getUpdateTime() { if (updatedAt == null) { // Older wallets did not store this field. Set to the epoch. updatedAt = new Date(0); } return updatedAt; } public void setUpdateTime(Date updatedAt) { this.updatedAt = updatedAt; } /** * These constants are a part of a scriptSig signature on the inputs. They define the details of how a * transaction can be redeemed, specifically, they control how the hash of the transaction is calculated. */ public enum SigHash { ALL(1), NONE(2), SINGLE(3), ANYONECANPAY(0x80), // Caution: Using this type in isolation is non-standard. Treated similar to ANYONECANPAY_ALL. ANYONECANPAY_ALL(0x81), ANYONECANPAY_NONE(0x82), ANYONECANPAY_SINGLE(0x83), UNSET(0); // Caution: Using this type in isolation is non-standard. Treated similar to ALL. public final int value; /** * @param value */ private SigHash(final int value) { this.value = value; } /** * @return the value as a byte */ public byte byteValue() { return (byte) this.value; } } /** * @deprecated Instead use SigHash.ANYONECANPAY.value or SigHash.ANYONECANPAY.byteValue() as appropriate. */ public static final byte SIGHASH_ANYONECANPAY_VALUE = (byte) 0x80; @Override protected void unCache() { super.unCache(); hash = null; } protected static int calcLength(byte[] buf, int offset) { VarInt varint; // jump past version (uint32) int cursor = offset + 4; int i; long scriptLen; varint = new VarInt(buf, cursor); long txInCount = varint.value; cursor += varint.getOriginalSizeInBytes(); for (i = 0; i < txInCount; i++) { // 36 = length of previous_outpoint cursor += 36; varint = new VarInt(buf, cursor); scriptLen = varint.value; // 4 = length of sequence field (unint32) cursor += scriptLen + 4 + varint.getOriginalSizeInBytes(); } varint = new VarInt(buf, cursor); long txOutCount = varint.value; cursor += varint.getOriginalSizeInBytes(); for (i = 0; i < txOutCount; i++) { // 8 = length of tx value field (uint64) cursor += 8; varint = new VarInt(buf, cursor); scriptLen = varint.value; cursor += scriptLen + varint.getOriginalSizeInBytes(); } // 4 = length of lock_time field (uint32) return cursor - offset + 4; } @Override protected void parse() throws ProtocolException { cursor = offset; version = readUint32(); optimalEncodingMessageSize = 4; // First come the inputs. long numInputs = readVarInt(); optimalEncodingMessageSize += VarInt.sizeOf(numInputs); inputs = new ArrayList<TransactionInput>((int) numInputs); for (long i = 0; i < numInputs; i++) { TransactionInput input = new TransactionInput(params, this, payload, cursor, serializer); inputs.add(input); long scriptLen = readVarInt(TransactionOutPoint.MESSAGE_LENGTH); optimalEncodingMessageSize += TransactionOutPoint.MESSAGE_LENGTH + VarInt.sizeOf(scriptLen) + scriptLen + 4; cursor += scriptLen + 4; } // Now the outputs long numOutputs = readVarInt(); optimalEncodingMessageSize += VarInt.sizeOf(numOutputs); outputs = new ArrayList<TransactionOutput>((int) numOutputs); for (long i = 0; i < numOutputs; i++) { TransactionOutput output = new TransactionOutput(params, this, payload, cursor, serializer); outputs.add(output); long scriptLen = readVarInt(8); optimalEncodingMessageSize += 8 + VarInt.sizeOf(scriptLen) + scriptLen; cursor += scriptLen; } lockTime = readUint32(); optimalEncodingMessageSize += 4; length = cursor - offset; } public int getOptimalEncodingMessageSize() { if (optimalEncodingMessageSize != 0) return optimalEncodingMessageSize; optimalEncodingMessageSize = getMessageSize(); return optimalEncodingMessageSize; } /** * The priority (coin age) calculation doesn't use the regular message size, but rather one adjusted downwards * for the number of inputs. The goal is to incentivise cleaning up the UTXO set with free transactions, if one * can do so. */ public int getMessageSizeForPriorityCalc() { int size = getMessageSize(); for (TransactionInput input : inputs) { // 41: min size of an input // 110: enough to cover a compressed pubkey p2sh redemption (somewhat arbitrary). int benefit = 41 + Math.min(110, input.getScriptSig().getProgram().length); if (size > benefit) size -= benefit; } return size; } /** * A coinbase transaction is one that creates a new coin. They are the first transaction in each block and their * value is determined by a formula that all implementations of Bitcoin share. In 2011 the value of a coinbase * transaction is 50 coins, but in future it will be less. A coinbase transaction is defined not only by its * position in a block but by the data in the inputs. */ public boolean isCoinBase() { return inputs.size() == 1 && inputs.get(0).isCoinBase(); } /** * A transaction is mature if it is either a building coinbase tx that is as deep or deeper than the required coinbase depth, or a non-coinbase tx. */ public boolean isMature() { if (!isCoinBase()) return true; if (getConfidence().getConfidenceType() != ConfidenceType.BUILDING) return false; return getConfidence().getDepthInBlocks() >= params.getSpendableCoinbaseDepth(); } @Override public String toString() { return toString(null); } /** * A human readable version of the transaction useful for debugging. The format is not guaranteed to be stable. * @param chain If provided, will be used to estimate lock times (if set). Can be null. */ public String toString(@Nullable AbstractBlockChain chain) { StringBuilder s = new StringBuilder(); s.append(" ").append(getHashAsString()).append('\n'); if (updatedAt != null) s.append(" updated: ").append(Utils.dateTimeFormat(updatedAt)).append('\n'); if (isTimeLocked()) { s.append(" time locked until "); if (lockTime < LOCKTIME_THRESHOLD) { s.append("block ").append(lockTime); if (chain != null) { s.append(" (estimated to be reached at ") .append(Utils.dateTimeFormat(chain.estimateBlockTime((int) lockTime))).append(')'); } } else { s.append(Utils.dateTimeFormat(lockTime * 1000)); } s.append('\n'); } if (isOptInFullRBF()) { s.append(" opts into full replace-by-fee\n"); } if (inputs.size() == 0) { s.append(" INCOMPLETE: No inputs!\n"); return s.toString(); } if (isCoinBase()) { String script; String script2; try { script = inputs.get(0).getScriptSig().toString(); script2 = outputs.get(0).getScriptPubKey().toString(); } catch (ScriptException e) { script = "???"; script2 = "???"; } s.append(" == COINBASE TXN (scriptSig ").append(script) .append(") (scriptPubKey ").append(script2).append(")\n"); return s.toString(); } for (TransactionInput in : inputs) { s.append(" "); s.append("in "); try { Script scriptSig = in.getScriptSig(); s.append(scriptSig); if (in.getValue() != null) s.append(" ").append(in.getValue().toFriendlyString()); s.append("\n "); s.append("outpoint:"); final TransactionOutPoint outpoint = in.getOutpoint(); s.append(outpoint.toString()); final TransactionOutput connectedOutput = outpoint.getConnectedOutput(); if (connectedOutput != null) { Script scriptPubKey = connectedOutput.getScriptPubKey(); if (scriptPubKey.isSentToAddress() || scriptPubKey.isPayToScriptHash()) { s.append(" hash160:"); s.append(Utils.HEX.encode(scriptPubKey.getPubKeyHash())); } } if (in.hasSequence()) { s.append("\n sequence:").append(Long.toHexString(in.getSequenceNumber())); if (in.isOptInFullRBF()) s.append(", opts into full RBF"); } } catch (Exception e) { s.append("[exception: ").append(e.getMessage()).append("]"); } s.append('\n'); } for (TransactionOutput out : outputs) { s.append(" "); s.append("out "); try { Script scriptPubKey = out.getScriptPubKey(); s.append(scriptPubKey); s.append(" "); s.append(out.getValue().toFriendlyString()); if (!out.isAvailableForSpending()) { s.append(" Spent"); } if (out.getSpentBy() != null) { s.append(" by "); s.append(out.getSpentBy().getParentTransaction().getHashAsString()); } } catch (Exception e) { s.append("[exception: ").append(e.getMessage()).append("]"); } s.append('\n'); } final Coin fee = getFee(); if (fee != null) { final int size = unsafeBitcoinSerialize().length; s.append(" fee ").append(fee.multiply(1000).divide(size).toFriendlyString()).append("/kB, ") .append(fee.toFriendlyString()).append(" for ").append(size).append(" bytes\n"); } if (purpose != null) s.append(" prps ").append(purpose).append('\n'); return s.toString(); } /** * Removes all the inputs from this transaction. * Note that this also invalidates the length attribute */ public void clearInputs() { unCache(); for (TransactionInput input : inputs) { input.setParent(null); } inputs.clear(); // You wanted to reserialize, right? this.length = this.unsafeBitcoinSerialize().length; } /** * Adds an input to this transaction that imports value from the given output. Note that this input is <i>not</i> * complete and after every input is added with {@link #addInput()} and every output is added with * {@link #addOutput()}, a {@link TransactionSigner} must be used to finalize the transaction and finish the inputs * off. Otherwise it won't be accepted by the network. * @return the newly created input. */ public TransactionInput addInput(TransactionOutput from) { return addInput(new TransactionInput(params, this, from)); } /** * Adds an input directly, with no checking that it's valid. * @return the new input. */ public TransactionInput addInput(TransactionInput input) { unCache(); input.setParent(this); inputs.add(input); adjustLength(inputs.size(), input.length); return input; } /** * Creates and adds an input to this transaction, with no checking that it's valid. * @return the newly created input. */ public TransactionInput addInput(Sha256Hash spendTxHash, long outputIndex, Script script) { return addInput(new TransactionInput(params, this, script.getProgram(), new TransactionOutPoint(params, outputIndex, spendTxHash))); } /** * Adds a new and fully signed input for the given parameters. Note that this method is <b>not</b> thread safe * and requires external synchronization. Please refer to general documentation on Bitcoin scripting and contracts * to understand the values of sigHash and anyoneCanPay: otherwise you can use the other form of this method * that sets them to typical defaults. * * @throws ScriptException if the scriptPubKey is not a pay to address or pay to pubkey script. */ public TransactionInput addSignedInput(TransactionOutPoint prevOut, Script scriptPubKey, ECKey sigKey, SigHash sigHash, boolean anyoneCanPay) throws ScriptException { // Verify the API user didn't try to do operations out of order. checkState(!outputs.isEmpty(), "Attempting to sign tx without outputs."); TransactionInput input = new TransactionInput(params, this, new byte[]{}, prevOut); addInput(input); Sha256Hash hash = hashForSignature(inputs.size() - 1, scriptPubKey, sigHash, anyoneCanPay); ECKey.ECDSASignature ecSig = sigKey.sign(hash); TransactionSignature txSig = new TransactionSignature(ecSig, sigHash, anyoneCanPay); if (scriptPubKey.isSentToRawPubKey()) input.setScriptSig(ScriptBuilder.createInputScript(txSig)); else if (scriptPubKey.isSentToAddress()) input.setScriptSig(ScriptBuilder.createInputScript(txSig, sigKey)); else throw new ScriptException("Don't know how to sign for this kind of scriptPubKey: " + scriptPubKey); return input; } /** * Same as {@link #addSignedInput(TransactionOutPoint, org.bitcoinj.script.Script, ECKey, org.bitcoinj.core.Transaction.SigHash, boolean)} * but defaults to {@link SigHash#ALL} and "false" for the anyoneCanPay flag. This is normally what you want. */ public TransactionInput addSignedInput(TransactionOutPoint prevOut, Script scriptPubKey, ECKey sigKey) throws ScriptException { return addSignedInput(prevOut, scriptPubKey, sigKey, SigHash.ALL, false); } /** * Adds an input that points to the given output and contains a valid signature for it, calculated using the * signing key. */ public TransactionInput addSignedInput(TransactionOutput output, ECKey signingKey) { return addSignedInput(output.getOutPointFor(), output.getScriptPubKey(), signingKey); } /** * Adds an input that points to the given output and contains a valid signature for it, calculated using the * signing key. */ public TransactionInput addSignedInput(TransactionOutput output, ECKey signingKey, SigHash sigHash, boolean anyoneCanPay) { return addSignedInput(output.getOutPointFor(), output.getScriptPubKey(), signingKey, sigHash, anyoneCanPay); } /** * Removes all the outputs from this transaction. * Note that this also invalidates the length attribute */ public void clearOutputs() { unCache(); for (TransactionOutput output : outputs) { output.setParent(null); } outputs.clear(); // You wanted to reserialize, right? this.length = this.unsafeBitcoinSerialize().length; } /** * Adds the given output to this transaction. The output must be completely initialized. Returns the given output. */ public TransactionOutput addOutput(TransactionOutput to) { unCache(); to.setParent(this); outputs.add(to); adjustLength(outputs.size(), to.length); return to; } /** * Creates an output based on the given address and value, adds it to this transaction, and returns the new output. */ public TransactionOutput addOutput(Coin value, Address address) { return addOutput(new TransactionOutput(params, this, value, address)); } /** * Creates an output that pays to the given pubkey directly (no address) with the given value, adds it to this * transaction, and returns the new output. */ public TransactionOutput addOutput(Coin value, ECKey pubkey) { return addOutput(new TransactionOutput(params, this, value, pubkey)); } /** * Creates an output that pays to the given script. The address and key forms are specialisations of this method, * you won't normally need to use it unless you're doing unusual things. */ public TransactionOutput addOutput(Coin value, Script script) { return addOutput(new TransactionOutput(params, this, value, script.getProgram())); } /** * Calculates a signature that is valid for being inserted into the input at the given position. This is simply * a wrapper around calling {@link Transaction#hashForSignature(int, byte[], org.bitcoinj.core.Transaction.SigHash, boolean)} * followed by {@link ECKey#sign(Sha256Hash)} and then returning a new {@link TransactionSignature}. The key * must be usable for signing as-is: if the key is encrypted it must be decrypted first external to this method. * * @param inputIndex Which input to calculate the signature for, as an index. * @param key The private key used to calculate the signature. * @param redeemScript Byte-exact contents of the scriptPubKey that is being satisified, or the P2SH redeem script. * @param hashType Signing mode, see the enum for documentation. * @param anyoneCanPay Signing mode, see the SigHash enum for documentation. * @return A newly calculated signature object that wraps the r, s and sighash components. */ public TransactionSignature calculateSignature(int inputIndex, ECKey key, byte[] redeemScript, SigHash hashType, boolean anyoneCanPay) { Sha256Hash hash = hashForSignature(inputIndex, redeemScript, hashType, anyoneCanPay); return new TransactionSignature(key.sign(hash), hashType, anyoneCanPay); } /** * Calculates a signature that is valid for being inserted into the input at the given position. This is simply * a wrapper around calling {@link Transaction#hashForSignature(int, byte[], org.bitcoinj.core.Transaction.SigHash, boolean)} * followed by {@link ECKey#sign(Sha256Hash)} and then returning a new {@link TransactionSignature}. * * @param inputIndex Which input to calculate the signature for, as an index. * @param key The private key used to calculate the signature. * @param redeemScript The scriptPubKey that is being satisified, or the P2SH redeem script. * @param hashType Signing mode, see the enum for documentation. * @param anyoneCanPay Signing mode, see the SigHash enum for documentation. * @return A newly calculated signature object that wraps the r, s and sighash components. */ public TransactionSignature calculateSignature(int inputIndex, ECKey key, Script redeemScript, SigHash hashType, boolean anyoneCanPay) { Sha256Hash hash = hashForSignature(inputIndex, redeemScript.getProgram(), hashType, anyoneCanPay); return new TransactionSignature(key.sign(hash), hashType, anyoneCanPay); } /** * Calculates a signature that is valid for being inserted into the input at the given position. This is simply * a wrapper around calling {@link Transaction#hashForSignature(int, byte[], org.bitcoinj.core.Transaction.SigHash, boolean)} * followed by {@link ECKey#sign(Sha256Hash)} and then returning a new {@link TransactionSignature}. The key * must be usable for signing as-is: if the key is encrypted it must be decrypted first external to this method. * * @param inputIndex Which input to calculate the signature for, as an index. * @param key The private key used to calculate the signature. * @param aesKey The AES key to use for decryption of the private key. If null then no decryption is required. * @param redeemScript Byte-exact contents of the scriptPubKey that is being satisified, or the P2SH redeem script. * @param hashType Signing mode, see the enum for documentation. * @param anyoneCanPay Signing mode, see the SigHash enum for documentation. * @return A newly calculated signature object that wraps the r, s and sighash components. */ public TransactionSignature calculateSignature(int inputIndex, ECKey key, @Nullable KeyParameter aesKey, byte[] redeemScript, SigHash hashType, boolean anyoneCanPay) { Sha256Hash hash = hashForSignature(inputIndex, redeemScript, hashType, anyoneCanPay); return new TransactionSignature(key.sign(hash, aesKey), hashType, anyoneCanPay); } /** * Calculates a signature that is valid for being inserted into the input at the given position. This is simply * a wrapper around calling {@link Transaction#hashForSignature(int, byte[], org.bitcoinj.core.Transaction.SigHash, boolean)} * followed by {@link ECKey#sign(Sha256Hash)} and then returning a new {@link TransactionSignature}. * * @param inputIndex Which input to calculate the signature for, as an index. * @param key The private key used to calculate the signature. * @param aesKey The AES key to use for decryption of the private key. If null then no decryption is required. * @param redeemScript The scriptPubKey that is being satisified, or the P2SH redeem script. * @param hashType Signing mode, see the enum for documentation. * @param anyoneCanPay Signing mode, see the SigHash enum for documentation. * @return A newly calculated signature object that wraps the r, s and sighash components. */ public TransactionSignature calculateSignature(int inputIndex, ECKey key, @Nullable KeyParameter aesKey, Script redeemScript, SigHash hashType, boolean anyoneCanPay) { Sha256Hash hash = hashForSignature(inputIndex, redeemScript.getProgram(), hashType, anyoneCanPay); return new TransactionSignature(key.sign(hash, aesKey), hashType, anyoneCanPay); } /** * <p>Calculates a signature hash, that is, a hash of a simplified form of the transaction. How exactly the transaction * is simplified is specified by the type and anyoneCanPay parameters.</p> * * <p>This is a low level API and when using the regular {@link Wallet} class you don't have to call this yourself. * When working with more complex transaction types and contracts, it can be necessary. When signing a P2SH output * the redeemScript should be the script encoded into the scriptSig field, for normal transactions, it's the * scriptPubKey of the output you're signing for.</p> * * @param inputIndex input the signature is being calculated for. Tx signatures are always relative to an input. * @param redeemScript the bytes that should be in the given input during signing. * @param type Should be SigHash.ALL * @param anyoneCanPay should be false. */ public Sha256Hash hashForSignature(int inputIndex, byte[] redeemScript, SigHash type, boolean anyoneCanPay) { byte sigHashType = (byte) TransactionSignature.calcSigHashValue(type, anyoneCanPay); return hashForSignature(inputIndex, redeemScript, sigHashType); } /** * <p>Calculates a signature hash, that is, a hash of a simplified form of the transaction. How exactly the transaction * is simplified is specified by the type and anyoneCanPay parameters.</p> * * <p>This is a low level API and when using the regular {@link Wallet} class you don't have to call this yourself. * When working with more complex transaction types and contracts, it can be necessary. When signing a P2SH output * the redeemScript should be the script encoded into the scriptSig field, for normal transactions, it's the * scriptPubKey of the output you're signing for.</p> * * @param inputIndex input the signature is being calculated for. Tx signatures are always relative to an input. * @param redeemScript the script that should be in the given input during signing. * @param type Should be SigHash.ALL * @param anyoneCanPay should be false. */ public Sha256Hash hashForSignature(int inputIndex, Script redeemScript, SigHash type, boolean anyoneCanPay) { int sigHash = TransactionSignature.calcSigHashValue(type, anyoneCanPay); return hashForSignature(inputIndex, redeemScript.getProgram(), (byte) sigHash); } /** * This is required for signatures which use a sigHashType which cannot be represented using SigHash and anyoneCanPay * See transaction c99c49da4c38af669dea436d3e73780dfdb6c1ecf9958baa52960e8baee30e73, which has sigHashType 0 */ public Sha256Hash hashForSignature(int inputIndex, byte[] connectedScript, byte sigHashType) { // The SIGHASH flags are used in the design of contracts, please see this page for a further understanding of // the purposes of the code in this method: // // https://en.bitcoin.it/wiki/Contracts try { // Create a copy of this transaction to operate upon because we need make changes to the inputs and outputs. // It would not be thread-safe to change the attributes of the transaction object itself. Transaction tx = this.params.getDefaultSerializer().makeTransaction(this.bitcoinSerialize()); // Clear input scripts in preparation for signing. If we're signing a fresh // transaction that step isn't very helpful, but it doesn't add much cost relative to the actual // EC math so we'll do it anyway. for (int i = 0; i < tx.inputs.size(); i++) { tx.inputs.get(i).clearScriptBytes(); } // This step has no purpose beyond being synchronized with Bitcoin Core's bugs. OP_CODESEPARATOR // is a legacy holdover from a previous, broken design of executing scripts that shipped in Bitcoin 0.1. // It was seriously flawed and would have let anyone take anyone elses money. Later versions switched to // the design we use today where scripts are executed independently but share a stack. This left the // OP_CODESEPARATOR instruction having no purpose as it was only meant to be used internally, not actually // ever put into scripts. Deleting OP_CODESEPARATOR is a step that should never be required but if we don't // do it, we could split off the main chain. connectedScript = Script.removeAllInstancesOfOp(connectedScript, ScriptOpCodes.OP_CODESEPARATOR); // Set the input to the script of its output. Bitcoin Core does this but the step has no obvious purpose as // the signature covers the hash of the prevout transaction which obviously includes the output script // already. Perhaps it felt safer to him in some way, or is another leftover from how the code was written. TransactionInput input = tx.inputs.get(inputIndex); input.setScriptBytes(connectedScript); if ((sigHashType & 0x1f) == SigHash.NONE.value) { // SIGHASH_NONE means no outputs are signed at all - the signature is effectively for a "blank cheque". tx.outputs = new ArrayList<TransactionOutput>(0); // The signature isn't broken by new versions of the transaction issued by other parties. for (int i = 0; i < tx.inputs.size(); i++) if (i != inputIndex) tx.inputs.get(i).setSequenceNumber(0); } else if ((sigHashType & 0x1f) == SigHash.SINGLE.value) { // SIGHASH_SINGLE means only sign the output at the same index as the input (ie, my output). if (inputIndex >= tx.outputs.size()) { // The input index is beyond the number of outputs, it's a buggy signature made by a broken // Bitcoin implementation. Bitcoin Core also contains a bug in handling this case: // any transaction output that is signed in this case will result in both the signed output // and any future outputs to this public key being steal-able by anyone who has // the resulting signature and the public key (both of which are part of the signed tx input). // Bitcoin Core's bug is that SignatureHash was supposed to return a hash and on this codepath it // actually returns the constant "1" to indicate an error, which is never checked for. Oops. return Sha256Hash.wrap("0100000000000000000000000000000000000000000000000000000000000000"); } // In SIGHASH_SINGLE the outputs after the matching input index are deleted, and the outputs before // that position are "nulled out". Unintuitively, the value in a "null" transaction is set to -1. tx.outputs = new ArrayList<TransactionOutput>(tx.outputs.subList(0, inputIndex + 1)); for (int i = 0; i < inputIndex; i++) tx.outputs.set(i, new TransactionOutput(tx.params, tx, Coin.NEGATIVE_SATOSHI, new byte[] {})); // The signature isn't broken by new versions of the transaction issued by other parties. for (int i = 0; i < tx.inputs.size(); i++) if (i != inputIndex) tx.inputs.get(i).setSequenceNumber(0); } if ((sigHashType & SigHash.ANYONECANPAY.value) == SigHash.ANYONECANPAY.value) { // SIGHASH_ANYONECANPAY means the signature in the input is not broken by changes/additions/removals // of other inputs. For example, this is useful for building assurance contracts. tx.inputs = new ArrayList<TransactionInput>(); tx.inputs.add(input); } ByteArrayOutputStream bos = new UnsafeByteArrayOutputStream(tx.length == UNKNOWN_LENGTH ? 256 : tx.length + 4); tx.bitcoinSerialize(bos); // We also have to write a hash type (sigHashType is actually an unsigned char) uint32ToByteStreamLE(0x000000ff & sigHashType, bos); // Note that this is NOT reversed to ensure it will be signed correctly. If it were to be printed out // however then we would expect that it is IS reversed. Sha256Hash hash = Sha256Hash.twiceOf(bos.toByteArray()); bos.close(); return hash; } catch (IOException e) { throw new RuntimeException(e); // Cannot happen. } } @Override protected void bitcoinSerializeToStream(OutputStream stream) throws IOException { uint32ToByteStreamLE(version, stream); stream.write(new VarInt(inputs.size()).encode()); for (TransactionInput in : inputs) in.bitcoinSerialize(stream); stream.write(new VarInt(outputs.size()).encode()); for (TransactionOutput out : outputs) out.bitcoinSerialize(stream); uint32ToByteStreamLE(lockTime, stream); } /** * Transactions can have an associated lock time, specified either as a block height or in seconds since the * UNIX epoch. A transaction is not allowed to be confirmed by miners until the lock time is reached, and * since Bitcoin 0.8+ a transaction that did not end its lock period (non final) is considered to be non * standard and won't be relayed or included in the memory pool either. */ public long getLockTime() { return lockTime; } /** * Transactions can have an associated lock time, specified either as a block height or in seconds since the * UNIX epoch. A transaction is not allowed to be confirmed by miners until the lock time is reached, and * since Bitcoin 0.8+ a transaction that did not end its lock period (non final) is considered to be non * standard and won't be relayed or included in the memory pool either. */ public void setLockTime(long lockTime) { unCache(); boolean seqNumSet = false; for (TransactionInput input : inputs) { if (input.getSequenceNumber() != TransactionInput.NO_SEQUENCE) { seqNumSet = true; break; } } if (lockTime != 0 && (!seqNumSet || inputs.isEmpty())) { // At least one input must have a non-default sequence number for lock times to have any effect. // For instance one of them can be set to zero to make this feature work. log.warn("You are setting the lock time on a transaction but none of the inputs have non-default sequence numbers. This will not do what you expect!"); } this.lockTime = lockTime; } /** * @return the version */ public long getVersion() { return version; } /** Returns an unmodifiable view of all inputs. */ public List<TransactionInput> getInputs() { return Collections.unmodifiableList(inputs); } /** Returns an unmodifiable view of all outputs. */ public List<TransactionOutput> getOutputs() { return Collections.unmodifiableList(outputs); } /** * <p>Returns the list of transacion outputs, whether spent or unspent, that match a wallet by address or that are * watched by a wallet, i.e., transaction outputs whose script's address is controlled by the wallet and transaction * outputs whose script is watched by the wallet.</p> * * @param transactionBag The wallet that controls addresses and watches scripts. * @return linked list of outputs relevant to the wallet in this transaction */ public List<TransactionOutput> getWalletOutputs(TransactionBag transactionBag){ List<TransactionOutput> walletOutputs = new LinkedList<TransactionOutput>(); for (TransactionOutput o : outputs) { if (!o.isMineOrWatched(transactionBag)) continue; walletOutputs.add(o); } return walletOutputs; } /** Randomly re-orders the transaction outputs: good for privacy */ public void shuffleOutputs() { Collections.shuffle(outputs); } /** Same as getInputs().get(index). */ public TransactionInput getInput(long index) { return inputs.get((int)index); } /** Same as getOutputs().get(index) */ public TransactionOutput getOutput(long index) { return outputs.get((int)index); } /** * Returns the confidence object for this transaction from the {@link org.bitcoinj.core.TxConfidenceTable} * referenced by the implicit {@link Context}. */ public TransactionConfidence getConfidence() { return getConfidence(Context.get()); } /** * Returns the confidence object for this transaction from the {@link org.bitcoinj.core.TxConfidenceTable} * referenced by the given {@link Context}. */ public TransactionConfidence getConfidence(Context context) { return getConfidence(context.getConfidenceTable()); } /** * Returns the confidence object for this transaction from the {@link org.bitcoinj.core.TxConfidenceTable} */ public TransactionConfidence getConfidence(TxConfidenceTable table) { if (confidence == null) confidence = table.getOrCreate(getHash()) ; return confidence; } /** Check if the transaction has a known confidence */ public boolean hasConfidence() { return getConfidence().getConfidenceType() != TransactionConfidence.ConfidenceType.UNKNOWN; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; return getHash().equals(((Transaction)o).getHash()); } @Override public int hashCode() { return getHash().hashCode(); } /** * Gets the count of regular SigOps in this transactions */ public int getSigOpCount() throws ScriptException { int sigOps = 0; for (TransactionInput input : inputs) sigOps += Script.getSigOpCount(input.getScriptBytes()); for (TransactionOutput output : outputs) sigOps += Script.getSigOpCount(output.getScriptBytes()); return sigOps; } /** * Check block height is in coinbase input script, for use after BIP 34 * enforcement is enabled. */ public void checkCoinBaseHeight(final int height) throws VerificationException { checkArgument(height >= Block.BLOCK_HEIGHT_GENESIS); checkState(isCoinBase()); // Check block height is in coinbase input script final TransactionInput in = this.getInputs().get(0); final ScriptBuilder builder = new ScriptBuilder(); builder.number(height); final byte[] expected = builder.build().getProgram(); final byte[] actual = in.getScriptBytes(); if (actual.length < expected.length) { throw new VerificationException.CoinbaseHeightMismatch("Block height mismatch in coinbase."); } for (int scriptIdx = 0; scriptIdx < expected.length; scriptIdx++) { if (actual[scriptIdx] != expected[scriptIdx]) { throw new VerificationException.CoinbaseHeightMismatch("Block height mismatch in coinbase."); } } } /** * <p>Checks the transaction contents for sanity, in ways that can be done in a standalone manner. * Does <b>not</b> perform all checks on a transaction such as whether the inputs are already spent. * Specifically this method verifies:</p> * * <ul> * <li>That there is at least one input and output.</li> * <li>That the serialized size is not larger than the max block size.</li> * <li>That no outputs have negative value.</li> * <li>That the outputs do not sum to larger than the max allowed quantity of coin in the system.</li> * <li>If the tx is a coinbase tx, the coinbase scriptSig size is within range. Otherwise that there are no * coinbase inputs in the tx.</li> * </ul> * * @throws VerificationException */ public void verify() throws VerificationException { if (inputs.size() == 0 || outputs.size() == 0) throw new VerificationException.EmptyInputsOrOutputs(); if (this.getMessageSize() > Block.MAX_BLOCK_SIZE) throw new VerificationException.LargerThanMaxBlockSize(); Coin valueOut = Coin.ZERO; HashSet<TransactionOutPoint> outpoints = new HashSet<TransactionOutPoint>(); for (TransactionInput input : inputs) { if (outpoints.contains(input.getOutpoint())) throw new VerificationException.DuplicatedOutPoint(); outpoints.add(input.getOutpoint()); } try { for (TransactionOutput output : outputs) { if (output.getValue().signum() < 0) // getValue() can throw IllegalStateException throw new VerificationException.NegativeValueOutput(); valueOut = valueOut.add(output.getValue()); if (params.hasMaxMoney() && valueOut.compareTo(params.getMaxMoney()) > 0) throw new IllegalArgumentException(); } } catch (IllegalStateException e) { throw new VerificationException.ExcessiveValue(); } catch (IllegalArgumentException e) { throw new VerificationException.ExcessiveValue(); } if (isCoinBase()) { if (inputs.get(0).getScriptBytes().length < 2 || inputs.get(0).getScriptBytes().length > 100) throw new VerificationException.CoinbaseScriptSizeOutOfRange(); } else { for (TransactionInput input : inputs) if (input.isCoinBase()) throw new VerificationException.UnexpectedCoinbaseInput(); } } /** * <p>A transaction is time locked if at least one of its inputs is non-final and it has a lock time</p> * * <p>To check if this transaction is final at a given height and time, see {@link Transaction#isFinal(int, long)} * </p> */ public boolean isTimeLocked() { if (getLockTime() == 0) return false; for (TransactionInput input : getInputs()) if (input.hasSequence()) return true; return false; } /** * Returns whether this transaction will opt into the * <a href="https://github.com/bitcoin/bips/blob/master/bip-0125.mediawiki">full replace-by-fee </a> semantics. */ public boolean isOptInFullRBF() { for (TransactionInput input : getInputs()) if (input.isOptInFullRBF()) return true; return false; } /** * <p>Returns true if this transaction is considered finalized and can be placed in a block. Non-finalized * transactions won't be included by miners and can be replaced with newer versions using sequence numbers. * This is useful in certain types of <a href="http://en.bitcoin.it/wiki/Contracts">contracts</a>, such as * micropayment channels.</p> * * <p>Note that currently the replacement feature is disabled in Bitcoin Core and will need to be * re-activated before this functionality is useful.</p> */ public boolean isFinal(int height, long blockTimeSeconds) { long time = getLockTime(); return time < (time < LOCKTIME_THRESHOLD ? height : blockTimeSeconds) || !isTimeLocked(); } /** * Returns either the lock time as a date, if it was specified in seconds, or an estimate based on the time in * the current head block if it was specified as a block time. */ public Date estimateLockTime(AbstractBlockChain chain) { if (lockTime < LOCKTIME_THRESHOLD) return chain.estimateBlockTime((int)getLockTime()); else return new Date(getLockTime()*1000); } /** * Returns the purpose for which this transaction was created. See the javadoc for {@link Purpose} for more * information on the point of this field and what it can be. */ public Purpose getPurpose() { return purpose; } /** * Marks the transaction as being created for the given purpose. See the javadoc for {@link Purpose} for more * information on the point of this field and what it can be. */ public void setPurpose(Purpose purpose) { this.purpose = purpose; } /** * Getter for {@link #exchangeRate}. */ @Nullable public ExchangeRate getExchangeRate() { return exchangeRate; } /** * Setter for {@link #exchangeRate}. */ public void setExchangeRate(ExchangeRate exchangeRate) { this.exchangeRate = exchangeRate; } /** * Returns the transaction {@link #memo}. */ public String getMemo() { return memo; } /** * Set the transaction {@link #memo}. It can be used to record the memo of the payment request that initiated the * transaction. */ public void setMemo(String memo) { this.memo = memo; } }