add Preconditions.checkArgumentNotNull which throws IAE (#59), add jd…

…k 17 to CI

* add Preconditions.checkArgumentNotNull which throws IllegalArgumentException when argument null
* add jdk 17 to ci.yml

.github/workflows/ci.yml

@@ -17,7 +17,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy: 
      matrix:
-      java: ['8', '11'] 
+      java: ['8', '11', '17'] 
     steps:
       - uses: actions/checkout@v2
       - name: Set up JDK ${{ matrix.java }} 

src/main/java/com/github/davidmoten/guavamini/Preconditions.java

@@ -15,6 +15,17 @@ public static <T> T checkNotNull(T t, String message) {
             throw new NullPointerException(message);
         return t;
     }
+
+    public static <T> T checkArgumentNotNull(T t) {
+        return checkArgumentNotNull(t, "argument cannot be null");
+    }
+
+    public static <T> T checkArgumentNotNull(T t, String message) {
+        if (t == null) {
+            throw new IllegalArgumentException(message);
+        } 
+        return t;
+    }
 
     public static void checkArgument(boolean b, String message) {
         if (!b)

src/test/java/com/github/davidmoten/guavamini/PreconditionsTest.java

@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 import org.junit.Assert;
 import org.junit.Test;
@@ -19,7 +20,7 @@ public void testNullThrowsException() {
     public void testNotNullDoesNotThrowException() {
         Preconditions.checkNotNull(new Object());
     }
-    
+
     @Test
     public void testNotNullReturnsTypedObject() {
         Integer n = 1;
@@ -62,4 +63,20 @@ public void testCoverage() {
         Asserts.assertIsUtilityClass(Preconditions.class);
     }
 
+    @Test
+    public void testCheckArgumentNotNullThrowsIAE() {
+        try {
+            Preconditions.checkArgumentNotNull(null);
+            Assert.fail();
+        } catch (IllegalArgumentException e) {
+            assertEquals("argument cannot be null", e.getMessage());
+        }
+    }
+
+    @Test
+    public void testCheckArgumentNotNullReturnsWhenNotNull() {
+        Object o = new Object();
+        assertTrue(o == Preconditions.checkArgumentNotNull(o));
+    }
+
 }