Introduced toJson() method

src/main/java/ch/dissem/msgpack/types/MPArray.java

@@ -25,6 +25,7 @@ public class MPArray<T extends MPType> implements MPType<List<T>>, List<T> {
         this.array = array;
     }
 
+    @SafeVarargs
     public MPArray(T... objects) {
         this.array = Arrays.asList(objects);
     }
@@ -179,17 +180,29 @@ public class MPArray<T extends MPType> implements MPType<List<T>>, List<T> {
 
     @Override
     public String toString() {
+        return toJson();
+    }
+
+    @Override
+    public String toJson() {
+        return toJson("");
+    }
+
+    String toJson(String indent) {
         StringBuilder result = new StringBuilder();
-        result.append('[');
+        result.append("[\n");
         Iterator<T> iterator = array.iterator();
+        String indent2 = indent + "  ";
         while (iterator.hasNext()) {
             T item = iterator.next();
-            result.append(item.toString());
+            result.append(indent2);
+            result.append(Utils.toJson(item, indent2));
             if (iterator.hasNext()) {
-                result.append(", ");
+                result.append(',');
             }
+            result.append('\n');
         }
-        result.append(']');
+        result.append("]");
         return result.toString();
     }
 

src/main/java/ch/dissem/msgpack/types/MPBinary.java

@@ -52,7 +52,12 @@ public class MPBinary implements MPType<byte[]> {
 
     @Override
     public String toString() {
-        return null; // TODO base64
+        return toJson();
+    }
+
+    @Override
+    public String toJson() {
+        return Utils.base64(value);
     }
 
     public static class Unpacker implements MPType.Unpacker<MPBinary> {

src/main/java/ch/dissem/msgpack/types/MPBoolean.java

@@ -48,6 +48,11 @@ public class MPBoolean implements MPType<Boolean> {
         return String.valueOf(value);
     }
 
+    @Override
+    public String toJson() {
+        return String.valueOf(value);
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPBoolean> {
 
         public boolean is(int firstByte) {

src/main/java/ch/dissem/msgpack/types/MPDouble.java

@@ -46,6 +46,11 @@ public class MPDouble implements MPType<Double> {
         return String.valueOf(value);
     }
 
+    @Override
+    public String toJson() {
+        return String.valueOf(value);
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPDouble> {
         public boolean is(int firstByte) {
             return firstByte == 0xCB;

src/main/java/ch/dissem/msgpack/types/MPFloat.java

@@ -46,6 +46,11 @@ public class MPFloat implements MPType<Float> {
         return String.valueOf(value);
     }
 
+    @Override
+    public String toJson() {
+        return String.valueOf(value);
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPFloat> {
         public boolean is(int firstByte) {
             return firstByte == 0xCA;

src/main/java/ch/dissem/msgpack/types/MPInteger.java

@@ -78,6 +78,11 @@ public class MPInteger implements MPType<Long> {
         return String.valueOf(value);
     }
 
+    @Override
+    public String toJson() {
+        return String.valueOf(value);
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPInteger> {
         public boolean is(int firstByte) {
             switch (firstByte) {

src/main/java/ch/dissem/msgpack/types/MPMap.java

@@ -123,22 +123,34 @@ public class MPMap<K extends MPType, V extends MPType> implements MPType<Map<K,
 
     @Override
     public String toString() {
+        return toJson();
+    }
+
+    String toJson(String indent) {
         StringBuilder result = new StringBuilder();
-        result.append('{');
+        result.append("{\n");
         Iterator<Map.Entry<K, V>> iterator = map.entrySet().iterator();
+        String indent2 = indent + "  ";
         while (iterator.hasNext()) {
             Map.Entry<K, V> item = iterator.next();
-            result.append(item.getKey().toString());
+            result.append(indent2);
+            result.append(Utils.toJson(item.getKey(), indent2));
             result.append(": ");
-            result.append(item.getValue().toString());
+            result.append(Utils.toJson(item.getValue(), indent2));
             if (iterator.hasNext()) {
-                result.append(", ");
+                result.append(',');
             }
+            result.append('\n');
         }
-        result.append('}');
+        result.append(indent).append("}");
         return result.toString();
     }
 
+    @Override
+    public String toJson() {
+        return toJson("");
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPMap> {
         private final Reader reader;
 

src/main/java/ch/dissem/msgpack/types/MPNil.java

@@ -33,6 +33,11 @@ public class MPNil implements MPType<Void> {
         return "null";
     }
 
+    @Override
+    public String toJson() {
+        return "null";
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPNil> {
 
         public boolean is(int firstByte) {

src/main/java/ch/dissem/msgpack/types/MPString.java

@@ -99,6 +99,50 @@ public class MPString implements MPType<String>, CharSequence {
         return value;
     }
 
+    @Override
+    public String toJson() {
+        StringBuilder result = new StringBuilder(value.length() + 4);
+        result.append('"');
+        for (int i = 0; i < value.length(); i++) {
+            char c = value.charAt(i);
+            switch (c) {
+                case '\\':
+                case '"':
+                case '/':
+                    result.append('\\').append(c);
+                    break;
+                case '\b':
+                    result.append("\\b");
+                    break;
+                case '\t':
+                    result.append("\\t");
+                    break;
+                case '\n':
+                    result.append("\\n");
+                    break;
+                case '\f':
+                    result.append("\\f");
+                    break;
+                case '\r':
+                    result.append("\\r");
+                    break;
+                default:
+                    if (c < ' ') {
+                        result.append("\\u");
+                        String hex = Integer.toHexString(c);
+                        for (int j = 0; j - hex.length() < 4; j++) {
+                            result.append('0');
+                        }
+                        result.append(hex);
+                    } else {
+                        result.append(c);
+                    }
+            }
+        }
+        result.append('"');
+        return result.toString();
+    }
+
     public static class Unpacker implements MPType.Unpacker<MPString> {
         public boolean is(int firstByte) {
             return firstByte == STR8_PREFIX || firstByte == STR16_PREFIX || firstByte == STR32_PREFIX

src/main/java/ch/dissem/msgpack/types/MPType.java

@@ -17,4 +17,6 @@ public interface MPType<T> {
     T getValue();
 
     void pack(OutputStream out) throws IOException;
+
+    String toJson();
 }

src/main/java/ch/dissem/msgpack/types/Utils.java

@@ -5,6 +5,8 @@ import java.io.InputStream;
 import java.nio.ByteBuffer;
 
 class Utils {
+    private static final char[] BASE64_CODES = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=".toCharArray();
+
     /**
      * Returns a {@link ByteBuffer} containing the next <code>count</code> bytes from the {@link InputStream}.
      */
@@ -20,4 +22,49 @@ class Utils {
         }
         return ByteBuffer.wrap(result);
     }
+
+    /**
+     * Helper method to decide which types support extra indention (for pretty printing JSON)
+     */
+    static String toJson(MPType<?> type, String indent) {
+        if (type instanceof MPMap) {
+            return ((MPMap) type).toJson(indent);
+        }
+        if (type instanceof MPArray) {
+            return ((MPArray) type).toJson(indent);
+        }
+        return type.toJson();
+    }
+
+    /**
+     * Slightly improved code from https://en.wikipedia.org/wiki/Base64
+     */
+    static String base64(byte[] data) {
+        StringBuilder result = new StringBuilder((data.length * 4) / 3 + 3);
+        int b;
+        for (int i = 0; i < data.length; i += 3) {
+            b = (data[i] & 0xFC) >> 2;
+            result.append(BASE64_CODES[b]);
+            b = (data[i] & 0x03) << 4;
+            if (i + 1 < data.length) {
+                b |= (data[i + 1] & 0xF0) >> 4;
+                result.append(BASE64_CODES[b]);
+                b = (data[i + 1] & 0x0F) << 2;
+                if (i + 2 < data.length) {
+                    b |= (data[i + 2] & 0xC0) >> 6;
+                    result.append(BASE64_CODES[b]);
+                    b = data[i + 2] & 0x3F;
+                    result.append(BASE64_CODES[b]);
+                } else {
+                    result.append(BASE64_CODES[b]);
+                    result.append('=');
+                }
+            } else {
+                result.append(BASE64_CODES[b]);
+                result.append("==");
+            }
+        }
+
+        return result.toString();
+    }
 }

src/test/resources/demo.json

@@ -1 +1,4 @@
-{"compact": true, "schema": 0}
+{
+  "compact": true,
+  "schema": 0
+}