Add another decorator using lambda expression: TextValidator

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/decorator/TextProcessor.java → DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/decorator/lambda/expression/TextProcessor.java

@@ -1,4 +1,4 @@
-package pl.mperor.lab.java.design.pattern.structural.decorator;
+package pl.mperor.lab.java.design.pattern.structural.decorator.lambda.expression;
 
 import java.util.Arrays;
 import java.util.function.UnaryOperator;

DesignPatterns/src/main/java/pl/mperor/lab/java/design/pattern/structural/decorator/lambda/expression/TextValidator.java

@@ -0,0 +1,34 @@
+package pl.mperor.lab.java.design.pattern.structural.decorator.lambda.expression;
+
+import java.util.function.Predicate;
+
+public class TextValidator {
+
+    private TextValidator() {
+    }
+
+    public static Predicate<String> notEmpty() {
+        return Predicate.not(String::isEmpty);
+    }
+
+    public static Predicate<String> lengthBetween(int min, int max) {
+        return minLength(min).and(maxLength(max));
+    }
+
+    public static Predicate<String> minLength(int min) {
+        return text -> text.length() >= min;
+    }
+
+    public static Predicate<String> maxLength(int max) {
+        return text -> text.length() >= max;
+    }
+
+    public static Predicate<String> numeric() {
+        return text -> text.matches("\\d+");
+    }
+
+    public static Predicate<String> nan() {
+        return numeric().negate();
+    }
+
+}

DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/structural/decorator/TextProcessorTest.java → DesignPatterns/src/test/java/pl/mperor/lab/java/design/pattern/structural/decorator/lambda/expression/TextProcessorAndValidatorTest.java

@@ -1,9 +1,9 @@
-package pl.mperor.lab.java.design.pattern.structural.decorator;
+package pl.mperor.lab.java.design.pattern.structural.decorator.lambda.expression;
 
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Test;
 
-public class TextProcessorTest {
+public class TextProcessorAndValidatorTest {
 
     @Test
     public void shouldAllowToCreateTextProcessorAsChainOfFunctions() {
@@ -23,4 +23,17 @@ public void shouldAllowToCreateTextProcessorAsChainOfFunctions() {
         );
     }
 
+    @Test
+    public void shouldAllowToCreateTextValidator() {
+        Assertions.assertTrue(
+                TextValidator.notEmpty()
+                        .and(TextValidator.nan())
+                        .and(TextValidator.lengthBetween(1, 3))
+                        .test("abc")
+        );
+
+        var blankOrNumeric = TextValidator.numeric().or(String::isBlank);
+        Assertions.assertTrue(blankOrNumeric.test(" ") && blankOrNumeric.test("123"));
+    }
+
 }