Merge pull request #13706 from ciphx/string_to_int_encapsulation

String to int encapsulation

core-java-modules/core-java-string-conversions/src/main/java/com/baeldung/stringtoint/StringToIntConverter.java

@@ -0,0 +1,52 @@
+package com.baeldung.stringtoint;
+
+import java.util.Optional;
+import org.apache.commons.lang3.math.NumberUtils;
+
+public class StringToIntConverter {
+    
+    private StringToIntConverter() {
+    }
+
+    public static Integer convertStringToIntUsingIntegerParseInt(String input){
+        try {
+            return Integer.parseInt(input);
+        } catch (NumberFormatException e) {
+            // log or handle the error
+            return Integer.MIN_VALUE;
+        }
+    }
+
+    public static Integer convertStringToIntUsingIntegerValueOf(String input){
+        try {
+            return Integer.valueOf(input);
+        } catch (NumberFormatException e) {
+            // log or handle the error
+            return Integer.MIN_VALUE;
+        }
+    }
+
+    public static Integer convertStringToIntUsingIntegerDecode(String input){
+        try {
+            return Integer.decode(input);
+        } catch (Exception e) {
+            // log or handle the error
+            return Integer.MIN_VALUE;
+        }
+    }
+
+    public static Integer convertStringToIntUsingOptional(String input){
+        Optional<Integer> parsedInt;
+        try {
+            parsedInt = Optional.of(Integer.parseInt(input));
+        } catch (Exception e) {
+            // log or handle the error
+            parsedInt = Optional.empty();
+        }
+        return parsedInt.orElse(Integer.MIN_VALUE);
+    }
+
+    public static int convertStringToIntUsingNumberUtils(String input){
+        return NumberUtils.toInt(input, Integer.MIN_VALUE);
+    }
+}

core-java-modules/core-java-string-conversions/src/test/java/com/baeldung/stringtoint/StringToIntConverterUnitTest.java

@@ -0,0 +1,53 @@
+package com.baeldung.stringtoint;
+
+import java.util.Arrays;
+import java.util.List;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+class StringToIntConverterUnitTest {
+
+    @Test
+    void whenConvertingIntToString_thenInvalidCasesReturnIntegerMinValue() {
+        List<TestData> testData = Arrays.asList(
+                new TestData("", Integer.MIN_VALUE),
+                new TestData(null, Integer.MIN_VALUE),
+                new TestData("23,56", Integer.MIN_VALUE),
+                new TestData("2147483648", Integer.MIN_VALUE),
+                new TestData("-2147483649", Integer.MIN_VALUE),
+                new TestData("hello", Integer.MIN_VALUE)
+        );
+        testData.forEach(data -> {
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingIntegerParseInt(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingIntegerValueOf(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingOptional(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingIntegerDecode(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingNumberUtils(data.input));
+        });
+    }
+
+    @Test
+    void whenConvertingIntToString_thenValidCasesReturnUnboxedInt() {
+        List<TestData> testData = Arrays.asList(
+                new TestData("23", 23),
+                new TestData("-23", -23)
+        );
+        testData.forEach(data -> {
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingIntegerParseInt(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingIntegerValueOf(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingOptional(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingNumberUtils(data.input));
+                Assertions.assertEquals(data.expectedOutput, StringToIntConverter.convertStringToIntUsingIntegerDecode(data.input));
+        });
+    }
+
+    public static class TestData{
+        String input;
+        Integer expectedOutput;
+
+        TestData(String input, Integer expectedOutput){
+            this.input = input;
+            this.expectedOutput = expectedOutput;
+        }
+    }
+}