Task 2

pom.xml

@@ -6,8 +6,22 @@
     <artifactId>javatest1</artifactId>
     <version>1.0</version>
     <packaging>jar</packaging>
+
     <dependencies>
-
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.11</version>
+            <scope>test</scope>
+        </dependency>
+
+        <dependency>
+            <groupId>commons-codec</groupId>
+            <artifactId>commons-codec</artifactId>
+            <version>1.8</version>
+            <scope>test</scope>
+        </dependency>
+
     </dependencies>
     <build>
         <plugins>

src/main/java/com/getintent/interview/TreeNode.java

@@ -4,13 +4,30 @@
 import java.util.List;
 
 public class TreeNode {
+
     private int value;
     private List<TreeNode> children = new ArrayList<>();
 
     public TreeNode(int value) {
         this.value = value;
     }
 
+    public List<TreeNode> getChildren() {
+        return children;
+    }
+
+    public void setChildren(List<TreeNode> children) {
+        this.children = children;
+    }
+
+    public int getValue() {
+        return value;
+    }
+
+    public void setValue(int value) {
+        this.value = value;
+    }
+
     public void addChild(TreeNode child) {
         children.add(child);
     }

src/main/java/com/getintent/interview/TreeWriterImpl.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (c) 2013
+ * Kozlov Nikita
+ */
+package com.getintent.interview;
+
+import java.io.IOException;
+import java.io.Writer;
+
+/**
+ * @author Kozlov Nikita
+ */
+public class TreeWriterImpl implements TreeWriter {
+
+    private static final String INDENT = "    ";
+
+    private TreeNode treeNode;
+
+    @Override
+    public void write(TreeNode node, Writer w) {
+        this.treeNode = node;
+        if (treeNode != null) {
+            try {
+                this.write(w, 0);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        } else {
+            throw new IllegalArgumentException("Treenode can not be null.");
+        }
+    }
+
+    // ===================================================================================================================
+    // = Implementation
+    // ===================================================================================================================
+
+    private void write(Writer w, int depth) throws IOException {
+        for (int i = 0; i < depth; i++) {
+            w.append(INDENT);
+        }
+        w.append(String.valueOf(this.treeNode.getValue()))
+                .append("\n");
+        w.flush();
+        for (TreeNode node : treeNode.getChildren()) {
+            treeNode = node;
+            write(w, depth + 1);
+        }
+    }
+}

src/test/java/com/getintent/interview/TreeWriterImplTest.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2013
+ * Kozlov Nikita
+ */
+package com.getintent.interview;
+
+import org.apache.commons.codec.digest.DigestUtils;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.*;
+
+/**
+ * @author Kozlov Nikita
+ */
+public class TreeWriterImplTest {
+
+    private Writer writer;
+    private TreeNode rootNode;
+    private final static String FILE_PATH_ACTUAL = "src/test/java/tree-out-actual.TXT";
+    private final static String FILE_PATH_EXPECTED = "src/test/java/tree-out-expected.TXT";
+
+    @Before
+    public void setUp() throws Exception {
+        this.rootNode = new TreeNode(6);
+        TreeNode treeNode10 = new TreeNode(10);
+        TreeNode treeNode7 = new TreeNode(7);
+        TreeNode treeNode13 = new TreeNode(13);
+        TreeNode treeNode16 = new TreeNode(16);
+        TreeNode treeNode21 = new TreeNode(21);
+        TreeNode treeNode3 = new TreeNode(3);
+        TreeNode treeNode4 = new TreeNode(4);
+
+        rootNode.addChild(treeNode7);
+        rootNode.addChild(treeNode10);
+        rootNode.addChild(treeNode13);
+        treeNode13.addChild(treeNode16);
+        treeNode13.addChild(treeNode21);
+        treeNode7.addChild(treeNode3);
+        treeNode3.addChild(treeNode4);
+        File file = new File(FILE_PATH_ACTUAL);
+        this.writer = new FileWriter(file);
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (this.writer != null) {
+            this.writer.close();
+        }
+    }
+
+    @Test
+    public void testWrite() throws Exception {
+        TreeWriter treeWriter = new TreeWriterImpl();
+        treeWriter.write(this.rootNode, this.writer);
+        writer.close();
+        String expectedCheckSum = this.getCheckSumFile(FILE_PATH_EXPECTED);
+        String actualCheckSum = this.getCheckSumFile(FILE_PATH_ACTUAL);
+        Assert.assertEquals(expectedCheckSum, actualCheckSum);
+    }
+
+    // ===================================================================================================================
+    // = Implementation
+    // ===================================================================================================================
+
+    private String getCheckSumFile(String filePath) {
+        String checksum = null;
+        try {
+            checksum = DigestUtils.md5Hex(new FileInputStream(filePath));
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+        return checksum;
+    }
+}

src/test/java/tree-out-expected.txt

@@ -0,0 +1,8 @@
+6
+    7
+        3
+            4
+    10
+    13
+        16
+        21