Added support for MySQL JSON type

Added support for the JSON type added to MySQL 5.7. This required adding a new `ColumnType` and a new method to deserialize the JSON value, although the deserialization simply returns the `byte[]` containing the internal binary representation of the JSON value.

In order to be useful, this binary representation needs to be parsed into something more useful. A new `JsonBinary` class was created that can perform this parsing and delegate to a `JsonFormatter` implementation when JSON objects or arrays are started/ended, when various name-value pairs are encountered in an object, when values are encountered in an array, and when scalar values are encountered (outside of a JSON object or array, which is not really standard JSON).

Since many clients will simply want to obtain a JSON string representation of the JSON value, a `JsonStringFormatter` class was added, and a `JsonBinary.parseAsString` utility method added to conveniently obtain the JSON string representation. Of course, if this is not sufficient, clients can either subclass `JsonStringFormatter` to customize the behavior or implement their own `JsonFormatter` with completely custom behavior.

Quite a few integration test methods were added to insert various JSON values into a table, read the corresponding `WriteRowsEventData` event for the INSERT, extract the binary JSON value from the event, and then compare the string representation of the JSON value to expected forms.

Note that MySQL does allow for some values within JSON objects and arrays to be of types other than boolean, numeric, and strings (per the JSON spec). For example, MySQL `BLOB`, `DATE`, `TIME`, `DATETIME`, and `TIMESTAMP` values can be used and are encoded as "opaque types", although the `JsonBinary` parser does know how to interpret this opaque forms and call appropriate methods on the `JsonFormatter`. The `JsonStringFormatter` simply encodes the temporal types as formatted dates, times, or timestamps, while all other opaque values are represented as Base64-encoded strings.

Also, MySQL does allow scalar values to be used in `JSON` columns outside of JSON objects and arrays. This does not adhere to the JSON spec, and as such the `JsonStringFormatter` simply returns the string representations of these scalar values. (Any other logic can be customized.)

Author: rhauch

.gitignore

@@ -1,4 +1,8 @@
 .idea
 .iml
 .DS_Store
-target
+target
+.classpath
+.project
+.settings
+.vagrant

pom.xml

@@ -45,7 +45,7 @@
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
         <vagrant.bin>vagrant</vagrant.bin>
-        <vagrant.integration.box>${basedir}/supplement/vagrant/mysql-5.6.12-sandbox-prepackaged</vagrant.integration.box>
+        <vagrant.integration.box>${basedir}/supplement/vagrant/mysql-5.7.15-sandbox-prepackaged</vagrant.integration.box>
     </properties>
 
     <dependencies>
@@ -207,6 +207,8 @@
                             -Dvagrant.integration.box=supplement/vagrant/mysql-5.5.27-sandbox-prepackaged
                         mvn -P coverage verify \
                             -Dvagrant.integration.box=supplement/vagrant/mysql-5.6.12-sandbox-prepackaged
+                        mvn -P coverage verify \
+                            -Dvagrant.integration.box=supplement/vagrant/mysql-5.7.15-sandbox-prepackaged
 
                         # submit coverage report to coveralls
                         mvn -P coverage coveralls:jacoco -DrepoToken=&lt;coveralls.io&gt;

src/main/java/com/github/shyiko/mysql/binlog/event/deserialization/AbstractRowsEventDataDeserializer.java

@@ -15,10 +15,6 @@
  */
 package com.github.shyiko.mysql.binlog.event.deserialization;
 
-import com.github.shyiko.mysql.binlog.event.EventData;
-import com.github.shyiko.mysql.binlog.event.TableMapEventData;
-import com.github.shyiko.mysql.binlog.io.ByteArrayInputStream;
-
 import java.io.IOException;
 import java.io.Serializable;
 import java.math.BigDecimal;
@@ -27,6 +23,10 @@
 import java.util.Map;
 import java.util.TimeZone;
 
+import com.github.shyiko.mysql.binlog.event.EventData;
+import com.github.shyiko.mysql.binlog.event.TableMapEventData;
+import com.github.shyiko.mysql.binlog.io.ByteArrayInputStream;
+
 /**
  * Whole class is basically a mix of <a href="https://code.google.com/p/open-replicator">open-replicator</a>'s
  * AbstractRowEventParser and MySQLUtils. Main purpose here is to ease rows deserialization.<p>
@@ -170,6 +170,8 @@ protected Serializable deserializeCell(ColumnType type, int meta, int length, By
                 return deserializeSet(length, inputStream);
             case GEOMETRY:
                 return deserializeGeometry(meta, inputStream);
+            case JSON:
+                return deserializeJson(meta, inputStream);
             default:
                 throw new IOException("Unsupported type " + type);
         }
@@ -329,6 +331,21 @@ protected byte[] deserializeGeometry(int meta, ByteArrayInputStream inputStream)
         return inputStream.read(dataLength);
     }
 
+    /**
+     * Deserialize the {@code JSON} value on the input stream, and return MySQL's internal binary representation
+     * of the JSON value. See {@link com.github.shyiko.mysql.binlog.json.JsonBinary} for a utility to parse this
+     * binary representation into something more useful, including a string representation.
+     *
+     * @param meta the number of bytes in which the length of the JSON value is found first on the input stream
+     * @param inputStream the stream containing the JSON value
+     * @return the MySQL internal binary representation of the JSON value; may be null
+     * @throws IOException if there is a problem reading the input stream
+     */
+    protected byte[] deserializeJson(int meta, ByteArrayInputStream inputStream) throws IOException {
+        int blobLength = inputStream.readInteger(4);
+        return inputStream.read(blobLength);
+    }
+
     // checkstyle, please ignore ParameterNumber for the next line
     private static Long asUnixTime(int year, int month, int day, int hour, int minute, int second, int millis) {
         // https://dev.mysql.com/doc/refman/5.0/en/datetime.html
@@ -376,7 +393,7 @@ private static int[] split(long value, int divider, int length) {
     /**
      * see mysql/strings/decimal.c
      */
-    private static BigDecimal asBigDecimal(int precision, int scale, byte[] value) {
+    public static BigDecimal asBigDecimal(int precision, int scale, byte[] value) {
         boolean positive = (value[0] & 0x80) == 0x80;
         value[0] ^= 0x80;
         if (!positive) {

src/main/java/com/github/shyiko/mysql/binlog/event/deserialization/ColumnType.java

@@ -45,6 +45,7 @@ public enum ColumnType {
     TIMESTAMP_V2(17),
     DATETIME_V2(18),
     TIME_V2(19),
+    JSON(245),
     NEWDECIMAL(246),
     ENUM(247),
     SET(248),