fixes #709 When a default method defined in a mapper interface is cal…

…led, invoke the default method instead of looking for a bound mapper method.

src/main/java/org/apache/ibatis/binding/MapperProxy.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2009-2015 the original author or authors.
+ *    Copyright 2009-2016 the original author or authors.
  *
  *    Licensed under the Apache License, Version 2.0 (the "License");
  *    you may not use this file except in compliance with the License.
@@ -16,10 +16,14 @@
 package org.apache.ibatis.binding;
 
 import java.io.Serializable;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Constructor;
 import java.lang.reflect.InvocationHandler;
 import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 import java.util.Map;
 
+import org.apache.ibatis.lang.UsesJava7;
 import org.apache.ibatis.reflection.ExceptionUtil;
 import org.apache.ibatis.session.SqlSession;
 
@@ -42,12 +46,14 @@ public MapperProxy(SqlSession sqlSession, Class<T> mapperInterface, Map<Method,
 
   @Override
   public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
-    if (Object.class.equals(method.getDeclaringClass())) {
-      try {
+    try {
+      if (Object.class.equals(method.getDeclaringClass())) {
         return method.invoke(this, args);
-      } catch (Throwable t) {
-        throw ExceptionUtil.unwrapThrowable(t);
+      } else if (isDefaultMethod(method)) {
+        return invokeDefaultMethod(proxy, method, args);
       }
+    } catch (Throwable t) {
+      throw ExceptionUtil.unwrapThrowable(t);
     }
     final MapperMethod mapperMethod = cachedMapperMethod(method);
     return mapperMethod.execute(sqlSession, args);
@@ -62,4 +68,25 @@ private MapperMethod cachedMapperMethod(Method method) {
     return mapperMethod;
   }
 
+  @UsesJava7
+  private Object invokeDefaultMethod(Object proxy, Method method, Object[] args)
+      throws Throwable {
+    final Constructor<MethodHandles.Lookup> constructor = MethodHandles.Lookup.class
+        .getDeclaredConstructor(Class.class, int.class);
+    if (!constructor.isAccessible()) {
+      constructor.setAccessible(true);
+    }
+    final Class<?> declaringClass = method.getDeclaringClass();
+    return constructor.newInstance(declaringClass, MethodHandles.Lookup.PRIVATE)
+        .unreflectSpecial(method, declaringClass).bindTo(proxy).invokeWithArguments(args);
+  }
+
+  /**
+   * Backport of java.lang.reflect.Method#isDefault()
+   */
+  private boolean isDefaultMethod(Method method) {
+    return ((method.getModifiers()
+        & (Modifier.ABSTRACT | Modifier.PUBLIC | Modifier.STATIC)) == Modifier.PUBLIC)
+        && method.getDeclaringClass().isInterface();
+  }
 }

src/test/java/org/apache/ibatis/submitted/usesjava8/default_method/CreateDB.sql

@@ -0,0 +1,24 @@
+--
+--    Copyright 2009-2016 the original author or authors.
+--
+--    Licensed under the Apache License, Version 2.0 (the "License");
+--    you may not use this file except in compliance with the License.
+--    You may obtain a copy of the License at
+--
+--       http://www.apache.org/licenses/LICENSE-2.0
+--
+--    Unless required by applicable law or agreed to in writing, software
+--    distributed under the License is distributed on an "AS IS" BASIS,
+--    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+--    See the License for the specific language governing permissions and
+--    limitations under the License.
+--
+
+drop table users if exists;
+
+create table users (
+  id int,
+  name varchar(20)
+);
+
+insert into users (id, name) values(1, 'User1');

src/test/java/org/apache/ibatis/submitted/usesjava8/default_method/DefaultMethodTest.java

@@ -0,0 +1,81 @@
+/**
+ *    Copyright 2009-2016 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.submitted.usesjava8.default_method;
+
+import static org.junit.Assert.*;
+
+import java.io.Reader;
+import java.sql.Connection;
+
+import org.apache.ibatis.io.Resources;
+import org.apache.ibatis.jdbc.ScriptRunner;
+import org.apache.ibatis.lang.UsesJava8;
+import org.apache.ibatis.session.SqlSession;
+import org.apache.ibatis.session.SqlSessionFactory;
+import org.apache.ibatis.session.SqlSessionFactoryBuilder;
+import org.apache.ibatis.submitted.usesjava8.default_method.Mapper.SubMapper;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+
+public class DefaultMethodTest {
+
+  private static SqlSessionFactory sqlSessionFactory;
+
+  @BeforeClass
+  public static void setUp() throws Exception {
+    // create an SqlSessionFactory
+    Reader reader = Resources.getResourceAsReader(
+        "org/apache/ibatis/submitted/usesjava8/default_method/mybatis-config.xml");
+    sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
+    reader.close();
+
+    // populate in-memory database
+    SqlSession session = sqlSessionFactory.openSession();
+    Connection conn = session.getConnection();
+    reader = Resources.getResourceAsReader(
+        "org/apache/ibatis/submitted/usesjava8/default_method/CreateDB.sql");
+    ScriptRunner runner = new ScriptRunner(conn);
+    runner.setLogWriter(null);
+    runner.runScript(reader);
+    reader.close();
+    session.close();
+  }
+
+  @Test
+  public void shouldInvokeDefaultMethod() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      Mapper mapper = sqlSession.getMapper(Mapper.class);
+      User user = mapper.defaultGetUser(1);
+      assertEquals("User1", user.getName());
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
+  public void shouldInvokeDefaultMethodOfSubclass() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      SubMapper mapper = sqlSession.getMapper(SubMapper.class);
+      User user = mapper.defaultGetUser(1, "User1");
+      assertEquals("User1", user.getName());
+    } finally {
+      sqlSession.close();
+    }
+  }
+}

src/test/java/org/apache/ibatis/submitted/usesjava8/default_method/Mapper.java

@@ -0,0 +1,42 @@
+/**
+ *    Copyright 2009-2016 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.submitted.usesjava8.default_method;
+
+import org.apache.ibatis.annotations.Param;
+import org.apache.ibatis.annotations.Select;
+import org.apache.ibatis.lang.UsesJava8;
+import org.junit.experimental.categories.Category;
+
+@Category(UsesJava8.class)
+public interface Mapper {
+
+  @Select("select * from users where id = #{id}")
+  User getUserById(Integer id);
+
+  @Select("select * from users where id = #{id} and name = #{name}")
+  User getUserByIdAndName(@Param("id") Integer id, @Param("name") String name);
+
+  default User defaultGetUser(Object... args) {
+    return getUserById((Integer) args[0]);
+  }
+
+  static interface SubMapper extends Mapper {
+    default User defaultGetUser(Object... args) {
+      return getUserByIdAndName((Integer) args[0], (String) args[1]);
+    }
+  }
+
+}

src/test/java/org/apache/ibatis/submitted/usesjava8/default_method/User.java

@@ -0,0 +1,38 @@
+/**
+ *    Copyright 2009-2016 the original author or authors.
+ *
+ *    Licensed under the Apache License, Version 2.0 (the "License");
+ *    you may not use this file except in compliance with the License.
+ *    You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *    Unless required by applicable law or agreed to in writing, software
+ *    distributed under the License is distributed on an "AS IS" BASIS,
+ *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *    See the License for the specific language governing permissions and
+ *    limitations under the License.
+ */
+package org.apache.ibatis.submitted.usesjava8.default_method;
+
+public class User {
+
+  private Integer id;
+  private String name;
+
+  public Integer getId() {
+    return id;
+  }
+
+  public void setId(Integer id) {
+    this.id = id;
+  }
+
+  public String getName() {
+    return name;
+  }
+
+  public void setName(String name) {
+    this.name = name;
+  }
+}

src/test/java/org/apache/ibatis/submitted/usesjava8/default_method/mybatis-config.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<!--
+
+       Copyright 2009-2016 the original author or authors.
+
+       Licensed under the Apache License, Version 2.0 (the "License");
+       you may not use this file except in compliance with the License.
+       You may obtain a copy of the License at
+
+          http://www.apache.org/licenses/LICENSE-2.0
+
+       Unless required by applicable law or agreed to in writing, software
+       distributed under the License is distributed on an "AS IS" BASIS,
+       WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+       See the License for the specific language governing permissions and
+       limitations under the License.
+
+-->
+<!DOCTYPE configuration
+    PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
+    "http://mybatis.org/dtd/mybatis-3-config.dtd">
+
+<configuration>
+
+	<environments default="development">
+		<environment id="development">
+			<transactionManager type="JDBC">
+				<property name="" value="" />
+			</transactionManager>
+			<dataSource type="UNPOOLED">
+				<property name="driver" value="org.hsqldb.jdbcDriver" />
+				<property name="url" value="jdbc:hsqldb:mem:defaultmethod" />
+				<property name="username" value="sa" />
+			</dataSource>
+		</environment>
+	</environments>
+
+	<mappers>
+		<mapper class="org.apache.ibatis.submitted.usesjava8.default_method.Mapper" />
+		<mapper class="org.apache.ibatis.submitted.usesjava8.default_method.Mapper$SubMapper" />
+	</mappers>
+
+</configuration>