Moves pipeline to Java 11

pipeline/src/main/java/com/iluwatar/pipeline/ConvertToCharArrayHandler.java

@@ -36,11 +36,12 @@ class ConvertToCharArrayHandler implements Handler<String, char[]> {
 
   @Override
   public char[] process(String input) {
-    char[] characters = input.toCharArray();
-    LOGGER
-        .info(String.format("Current handler: %s, input is %s of type %s, output is %s, of type %s",
-            ConvertToCharArrayHandler.class, input, String.class, Arrays
-                .toString(characters), Character[].class));
+    var characters = input.toCharArray();
+    var string = Arrays.toString(characters);
+    LOGGER.info(
+        String.format("Current handler: %s, input is %s of type %s, output is %s, of type %s",
+            ConvertToCharArrayHandler.class, input, String.class, string, Character[].class)
+    );
 
     return characters;
   }

pipeline/src/main/java/com/iluwatar/pipeline/RemoveAlphabetsHandler.java

@@ -23,6 +23,7 @@
 
 package com.iluwatar.pipeline;
 
+import java.util.function.IntPredicate;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -36,18 +37,11 @@ class RemoveAlphabetsHandler implements Handler<String, String> {
 
   @Override
   public String process(String input) {
-    StringBuilder inputWithoutAlphabets = new StringBuilder();
+    var inputWithoutAlphabets = new StringBuilder();
+    var isAlphabetic = (IntPredicate) Character::isAlphabetic;
+    input.chars().filter(isAlphabetic.negate()).forEachOrdered(inputWithoutAlphabets::append);
 
-    for (int index = 0; index < input.length(); index++) {
-      char currentCharacter = input.charAt(index);
-      if (Character.isAlphabetic(currentCharacter)) {
-        continue;
-      }
-
-      inputWithoutAlphabets.append(currentCharacter);
-    }
-
-    String inputWithoutAlphabetsStr = inputWithoutAlphabets.toString();
+    var inputWithoutAlphabetsStr = inputWithoutAlphabets.toString();
     LOGGER.info(
         String.format(
             "Current handler: %s, input is %s of type %s, output is %s, of type %s",

pipeline/src/main/java/com/iluwatar/pipeline/RemoveDigitsHandler.java

@@ -23,6 +23,7 @@
 
 package com.iluwatar.pipeline;
 
+import java.util.function.IntPredicate;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -36,21 +37,17 @@ class RemoveDigitsHandler implements Handler<String, String> {
 
   @Override
   public String process(String input) {
-    StringBuilder inputWithoutDigits = new StringBuilder();
-
-    for (int index = 0; index < input.length(); index++) {
-      char currentCharacter = input.charAt(index);
-      if (Character.isDigit(currentCharacter)) {
-        continue;
-      }
-
-      inputWithoutDigits.append(currentCharacter);
-    }
-
-    String inputWithoutDigitsStr = inputWithoutDigits.toString();
-    LOGGER
-        .info(String.format("Current handler: %s, input is %s of type %s, output is %s, of type %s",
-            RemoveDigitsHandler.class, input, String.class, inputWithoutDigitsStr, String.class));
+    var inputWithoutDigits = new StringBuilder();
+    var isDigit = (IntPredicate) Character::isDigit;
+    input.chars().filter(isDigit.negate()).forEachOrdered(inputWithoutDigits::append);
+
+    var inputWithoutDigitsStr = inputWithoutDigits.toString();
+    LOGGER.info(
+        String.format(
+            "Current handler: %s, input is %s of type %s, output is %s, of type %s",
+            RemoveDigitsHandler.class, input, String.class, inputWithoutDigitsStr, String.class
+        )
+    );
 
     return inputWithoutDigitsStr;
   }

pipeline/src/test/java/com/iluwatar/pipeline/AppTest.java

@@ -32,7 +32,6 @@ public class AppTest {
 
   @Test
   public void test() {
-    String[] args = {};
-    App.main(args);
+    App.main(new String[]{});
   }
 }

pipeline/src/test/java/com/iluwatar/pipeline/PipelineTest.java

@@ -23,23 +23,23 @@
 
 package com.iluwatar.pipeline;
 
-import org.junit.jupiter.api.Test;
-
 import static org.junit.jupiter.api.Assertions.assertArrayEquals;
 
+import org.junit.jupiter.api.Test;
+
 /**
  * Test for {@link Pipeline}
  */
 public class PipelineTest {
 
   @Test
   public void testAddHandlersToPipeline() {
-    Pipeline<String, char[]> filters = new Pipeline<>(new RemoveAlphabetsHandler())
+    var filters = new Pipeline<>(new RemoveAlphabetsHandler())
         .addHandler(new RemoveDigitsHandler())
         .addHandler(new ConvertToCharArrayHandler());
 
     assertArrayEquals(
-        new char[] {'#', '!', '(', '&', '%', '#', '!'},
+        new char[]{'#', '!', '(', '&', '%', '#', '!'},
         filters.execute("#H!E(L&L0O%THE3R#34E!")
     );
   }