Left Pad lambda

build.gradle

@@ -11,6 +11,7 @@ subprojects {
     }
 
     dependencies {
+        testCompile 'junit:junit:4.12'
     }
 
 }

left-pad-lambda/build.gradle

@@ -0,0 +1,3 @@
+dependencies {
+    compile 'com.amazonaws:aws-lambda-java-core:1.2.0'
+}

left-pad-lambda/src/main/java/pl/grondek/aws/lambda/LeftPadFunction.java

@@ -0,0 +1,24 @@
+package pl.grondek.aws.lambda;
+
+import com.amazonaws.services.lambda.runtime.Context;
+import com.amazonaws.services.lambda.runtime.RequestHandler;
+
+public class LeftPadFunction implements RequestHandler<PadRequest, String> {
+    @Override
+    public String handleRequest(PadRequest request, Context context) {
+        if (request.getSize() < request.getString().length()) {
+            return request.getString();
+        } else {
+            final char[] input = request.getString().toCharArray();
+            char[] output = new char[request.getSize()];
+            final int paddingSize = request.getSize() - input.length;
+
+            for (int i = 0; i < paddingSize; i++) {
+                output[i] = request.getCharacter();
+            }
+
+            System.arraycopy(input, 0, output, paddingSize, input.length);
+            return String.valueOf(output);
+        }
+    }
+}

left-pad-lambda/src/main/java/pl/grondek/aws/lambda/PadRequest.java

@@ -0,0 +1,31 @@
+package pl.grondek.aws.lambda;
+
+public class PadRequest {
+    private String string;
+    private int size;
+    private char character;
+
+    public String getString() {
+        return string;
+    }
+
+    public void setString(String string) {
+        this.string = string;
+    }
+
+    public int getSize() {
+        return size;
+    }
+
+    public void setSize(int size) {
+        this.size = size;
+    }
+
+    public char getCharacter() {
+        return character;
+    }
+
+    public void setCharacter(char character) {
+        this.character = character;
+    }
+}

left-pad-lambda/src/test/java/pl/grondek/aws/lambda/LeftPadFunctionTest.java

@@ -0,0 +1,26 @@
+package pl.grondek.aws.lambda;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class LeftPadFunctionTest {
+
+    @Test
+    public void testFunction() {
+        // setup
+        LeftPadFunction leftPadFunction = new LeftPadFunction();
+
+        // given
+        PadRequest request = new PadRequest();
+        request.setCharacter(' ');
+        request.setSize(10);
+        request.setString("Test");
+
+        // when
+        final String response = leftPadFunction.handleRequest(request, null);
+
+        // then
+        Assert.assertEquals(response.length(), 10);
+        Assert.assertEquals(response, "      Test");
+    }
+}

settings.gradle

@@ -1,2 +1,3 @@
 rootProject.name = 'aws'
 
+include "left-pad-lambda"