From c5af2f3f3b9b6143b2536d9ce430b0a444a59ff6 Mon Sep 17 00:00:00 2001
From: MohamedHelmyKassab
 <137485958+MohamedHelmyKassab@users.noreply.github.com>
Date: Tue, 14 Nov 2023 07:53:16 +0200
Subject: [PATCH] This PR is related to BAEL-7181 (#15192)

* This commit is related to BAEL-7181

This commit aims to add a class "TimestampToLong.java" that provides several approaches to convert timestamp string into long.

* This commit is related to BAEL-7181

This commit aims to add a test class "TimestampToLongUnitTest.java" that provides several approaches to convert timestamp string into long.
---
 .../timestamptolong/TimestampToLong.java      | 32 ++++++++++++
 .../TimestampToLongUnitTest.java              | 52 +++++++++++++++++++
 2 files changed, 84 insertions(+)
 create mode 100644 core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java
 create mode 100644 core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java

diff --git a/core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java b/core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java
new file mode 100644
index 0000000000..2ebe30f4ff
--- /dev/null
+++ b/core-java-modules/core-java-datetime-conversion/src/main/java/com/baeldung/timestamptolong/TimestampToLong.java
@@ -0,0 +1,32 @@
+package com.baeldung.timestamptolong;
+
+import java.sql.Timestamp;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Date;
+
+public class TimestampToLong {
+    public void usingSimpleDateFormat() throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+        String currentDateString = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
+        long actualTimestamp = sdf.parse(currentDateString).getTime();
+    }
+
+    public void usingInstantClass() {
+        Instant instant = Instant.now();
+        long actualTimestamp = instant.toEpochMilli();
+    }
+
+    public void usingTimestamp() {
+        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
+        long actualTimestamp = timestamp.getTime();
+    }
+
+    public void usingJava8DateTime() {
+        LocalDateTime localDateTime = LocalDateTime.now();
+        long actualTimestamp = localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
+    }
+}
\ No newline at end of file
diff --git a/core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java b/core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java
new file mode 100644
index 0000000000..ede8f7792d
--- /dev/null
+++ b/core-java-modules/core-java-datetime-conversion/src/test/java/com/baeldung/timestamptolong/TimestampToLongUnitTest.java
@@ -0,0 +1,52 @@
+package com.baeldung.timestamptolong;
+
+import org.junit.Test;
+
+import java.sql.Timestamp;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.time.Instant;
+import java.time.LocalDateTime;
+import java.time.ZoneId;
+import java.util.Date;
+
+import static org.junit.Assert.assertTrue;
+
+public class TimestampToLongUnitTest {
+
+    private static final long TOLERANCE = 1000;
+
+    @Test
+    public void givenSimpleDateFormat_whenFormattingDate_thenTConvertToLong() throws ParseException {
+        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
+
+        String currentDateString = sdf.format(new Date());
+        long actualTimestamp = sdf.parse(currentDateString).getTime();
+
+        assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE);
+    }
+
+    @Test
+    public void givenInstantClass_whenGettingTimestamp_thenTConvertToLong() {
+        Instant instant = Instant.now();
+        long actualTimestamp = instant.toEpochMilli();
+
+        assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE);
+    }
+
+    @Test
+    public void givenTimestamp_whenCreatingTimestamp_thenTConvertToLong() {
+        Timestamp timestamp = new Timestamp(System.currentTimeMillis());
+        long actualTimestamp = timestamp.getTime();
+
+        assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE);
+    }
+
+    @Test
+    public void givenJava8DateTime_whenGettingTimestamp_thenTConvertToLong() {
+        LocalDateTime localDateTime = LocalDateTime.now();
+        long actualTimestamp = localDateTime.atZone(ZoneId.systemDefault()).toInstant().toEpochMilli();
+
+        assertTrue(Math.abs(System.currentTimeMillis() - actualTimestamp) < TOLERANCE);
+    }
+}