chore: add example

Signed-off-by: Ivan Ivanov <[email protected]>

examples/src/main/java/com/hedera/hashgraph/sdk/examples/LongTermScheduledTransactionExample.java

@@ -0,0 +1,245 @@
+/*-
+ *
+ * Hedera Java SDK
+ *
+ * Copyright (C) 2020 - 2024 Hedera Hashgraph, LLC
+ *
+ * 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 com.hedera.hashgraph.sdk.examples;
+
+import com.hedera.hashgraph.sdk.*;
+import com.hedera.hashgraph.sdk.logger.LogLevel;
+import com.hedera.hashgraph.sdk.logger.Logger;
+import io.github.cdimascio.dotenv.Dotenv;
+
+import java.time.Instant;
+import java.util.Collections;
+import java.util.Objects;
+
+/**
+ * How to long term schedule transactions (HIP-423).
+ */
+class LongTermScheduledTransactionExample {
+
+    /*
+     * See .env.sample in the examples folder root for how to specify values below
+     * or set environment variables with the same names.
+     */
+
+    /**
+     * Operator's account ID. Used to sign and pay for operations on Hedera.
+     */
+    private static final AccountId OPERATOR_ID = AccountId.fromString(
+        Objects.requireNonNull(Dotenv.load().get("OPERATOR_ID")));
+
+    /**
+     * Operator's private key.
+     */
+    private static final PrivateKey OPERATOR_KEY = PrivateKey.fromString(
+        Objects.requireNonNull(Dotenv.load().get("OPERATOR_KEY")));
+
+    /**
+     * HEDERA_NETWORK defaults to testnet if not specified in dotenv file. Network can be: localhost, testnet,
+     * previewnet or mainnet.
+     */
+    private static final String HEDERA_NETWORK = Dotenv.load().get("HEDERA_NETWORK", "testnet");
+
+    /**
+     * SDK_LOG_LEVEL defaults to SILENT if not specified in dotenv file. Log levels can be: TRACE, DEBUG, INFO, WARN,
+     * ERROR, SILENT.
+     * <p>
+     * Important pre-requisite: set simple logger log level to same level as the SDK_LOG_LEVEL, for example via VM
+     * options: -Dorg.slf4j.simpleLogger.log.com.hedera.hashgraph=trace
+     */
+    private static final String SDK_LOG_LEVEL = Dotenv.load().get("SDK_LOG_LEVEL", "SILENT");
+
+    public static void main(String[] args) throws Exception {
+        System.out.println("Long Term Scheduled Transaction Example Start!");
+
+        /*
+         * Step 0:
+         * Create and configure the SDK Client.
+         */
+        Client client = ClientHelper.forName(HEDERA_NETWORK);
+        // All generated transactions will be paid by this account and signed by this key.
+        client.setOperator(OPERATOR_ID, OPERATOR_KEY);
+        // Attach logger to the SDK Client.
+        client.setLogger(new Logger(LogLevel.valueOf(SDK_LOG_LEVEL)));
+
+        /*
+         * Step 1:
+         * Create key pairs
+         */
+        var privateKey1 = PrivateKey.generateED25519();
+        var publicKey1 = privateKey1.getPublicKey();
+        var privateKey2 = PrivateKey.generateED25519();
+
+        System.out.println("Creating a Key List..." +
+            "(with threshold, it will require 2 of 2 keys we generated to sign on anything modifying this account).");
+        KeyList thresholdKey = KeyList.withThreshold(2);
+        thresholdKey.add(privateKey1);
+        thresholdKey.add(privateKey2);
+        System.out.println("Created a Key List: " + thresholdKey);
+
+        /*
+         * Step 2:
+         * Create the account
+         */
+        System.out.println("Creating new account...(with the above Key List as an account key).");
+        var alice = new AccountCreateTransaction()
+            .setKey(thresholdKey)
+            .setInitialBalance(new Hbar(2))
+            .execute(client)
+            .getReceipt(client).accountId;
+        System.out.println("Created new account with ID: " + alice);
+
+        /*
+         * Step 3:
+         * Schedule a transfer transaction of 1 Hbar from the created account to the
+         * operator account with an expirationTime of
+         * 24 hours in the future and waitForExpiry=false
+         */
+        System.out.println("Creating new scheduled transaction with 1 day expiry");
+        TransferTransaction transfer = new TransferTransaction()
+            .addHbarTransfer(alice, new Hbar(1).negated())
+            .addHbarTransfer(client.getOperatorAccountId(), new Hbar(1));
+
+        int oneDayInSecs = 86400;
+        var scheduleId = transfer
+            .schedule()
+            .setWaitForExpiry(false)
+            .setExpirationTime(Instant.now().plusSeconds(oneDayInSecs))
+            .execute(client)
+            .getReceipt(client)
+            .scheduleId;
+
+        /*
+         * Step 4:
+         * Sign the transaction with one key and verify the transaction is not executed
+         */
+        System.out.println("Signing the new scheduled transaction with 1 key");
+        new ScheduleSignTransaction()
+            .setScheduleId(scheduleId)
+            .freezeWith(client)
+            .sign(privateKey1)
+            .execute(client)
+            .getReceipt(client);
+
+        ScheduleInfo info = new ScheduleInfoQuery()
+            .setScheduleId(scheduleId)
+            .execute(client);
+        System.out.println("Scheduled transaction is not yet executed. Executed at: "+ info.executedAt);
+
+        /*
+         * Step 5:
+         * Sign the transaction with the other key and verify the transaction executes successfully
+         */
+        var accountBalance = new AccountBalanceQuery()
+            .setAccountId(client.getOperatorAccountId())
+            .execute(client);
+        System.out.println("Account balance before schedule transfer: " + accountBalance.hbars);
+
+        System.out.println("Signing the new scheduled transaction with the 2nd key");
+        new ScheduleSignTransaction()
+            .setScheduleId(scheduleId)
+            .freezeWith(client)
+            .sign(privateKey2)
+            .execute(client)
+            .getReceipt(client);
+
+        accountBalance = new AccountBalanceQuery()
+            .setAccountId(client.getOperatorAccountId())
+            .execute(client);
+        System.out.println("Account balance after schedule transfer: " + accountBalance.hbars);
+
+        info = new ScheduleInfoQuery()
+            .setScheduleId(scheduleId)
+            .execute(client);
+        System.out.println("Scheduled transaction is executed. Executed at: "+ info.executedAt);
+
+        /*
+         * Step 6:
+         * Schedule another transfer transaction of 1 Hbar from the account to the operator account
+         * with an expirationTime of 30 seconds in the future and waitForExpiry=true .
+         */
+        System.out.println("Creating new scheduled transaction with 30 seconds expiry");
+        transfer = new TransferTransaction()
+            .addHbarTransfer(alice, new Hbar(1).negated())
+            .addHbarTransfer(client.getOperatorAccountId(), new Hbar(1));
+
+        var scheduleId2 = transfer
+            .schedule()
+            .setWaitForExpiry(true)
+            .setExpirationTime(Instant.now().plusSeconds(10))
+            .execute(client)
+            .getReceipt(client)
+            .scheduleId;
+        long startTime = System.currentTimeMillis();
+        long elapsedTime = 0;
+
+        /*
+         * Step 7:
+         * Sign the transaction with one key and verify the transaction is not executed
+         */
+        System.out.println("Signing the new scheduled transaction with 1 key");
+        new ScheduleSignTransaction()
+            .setScheduleId(scheduleId2)
+            .freezeWith(client)
+            .sign(privateKey1)
+            .execute(client)
+            .getReceipt(client);
+
+        info = new ScheduleInfoQuery()
+            .setScheduleId(scheduleId2)
+            .execute(client);
+        System.out.println("Scheduled transaction is not yet executed. Executed at: "+ info.executedAt);
+
+        /*
+         * Step 8:
+         * Update the account’s key to be only the one key
+         * that has already signed the scheduled transfer.
+         */
+        System.out.println("Updating Alice's key to be the 1st key");
+        new AccountUpdateTransaction()
+            .setAccountId(alice)
+            .setKey(publicKey1)
+            .freezeWith(client)
+            .sign(privateKey1)
+            .sign(privateKey2)
+            .execute(client)
+            .getReceipt(client);
+
+        /*
+         * Step 9:
+         * Verify that the transfer successfully executes roughly at the time of its expiration.
+         */
+        accountBalance = new AccountBalanceQuery()
+            .setAccountId(client.getOperatorAccountId())
+             .execute(client);
+
+        System.out.println("Account balance before schedule transfer: " + accountBalance.hbars);
+        while (elapsedTime < 10 * 1000) {
+            elapsedTime = System.currentTimeMillis() - startTime;
+            System.out.printf("Elapsed time: %.1f seconds\r", elapsedTime / 1000.0);
+            Thread.sleep(100); // Pause briefly to reduce CPU usage
+        }
+        accountBalance = new AccountBalanceQuery()
+            .setAccountId(client.getOperatorAccountId())
+            .execute(client);
+        System.out.println("Account balance after schedule transfer: " + accountBalance.hbars);
+
+        System.out.println("Long Term Scheduled Transaction Example Complete!");
+    }
+}