Allow calling a static provider method without instantiation

src/main/java/org/apache/ibatis/builder/annotation/ProviderSqlSource.java

@@ -15,7 +15,9 @@
  */
 package org.apache.ibatis.builder.annotation;
 
+import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -109,16 +111,16 @@ private SqlSource createSqlSource(Object parameterObject) {
       int bindParameterCount = providerMethodParameterTypes.length - (providerContext == null ? 0 : 1);
       String sql;
       if (providerMethodParameterTypes.length == 0) {
-        sql = (String) providerMethod.invoke(providerType.newInstance());
+        sql = invokeProviderMethod();
       } else if (bindParameterCount == 0) {
-        sql = (String) providerMethod.invoke(providerType.newInstance(), providerContext);
+        sql = invokeProviderMethod(providerContext);
       } else if (bindParameterCount == 1 &&
               (parameterObject == null || providerMethodParameterTypes[(providerContextIndex == null || providerContextIndex == 1) ? 0 : 1].isAssignableFrom(parameterObject.getClass()))) {
-        sql = (String) providerMethod.invoke(providerType.newInstance(), extractProviderMethodArguments(parameterObject));
+        sql = invokeProviderMethod(extractProviderMethodArguments(parameterObject));
       } else if (parameterObject instanceof Map) {
         @SuppressWarnings("unchecked")
         Map<String, Object> params = (Map<String, Object>) parameterObject;
-        sql = (String) providerMethod.invoke(providerType.newInstance(), extractProviderMethodArguments(params, providerMethodArgumentNames));
+        sql = invokeProviderMethod(extractProviderMethodArguments(params, providerMethodArgumentNames));
       } else {
         throw new BuilderException("Error invoking SqlProvider method ("
                 + providerType.getName() + "." + providerMethod.getName()
@@ -160,6 +162,14 @@ private Object[] extractProviderMethodArguments(Map<String, Object> params, Stri
     return args;
   }
 
+  private String invokeProviderMethod(Object... args) throws Exception {
+    Object targetObject = null;
+    if (!Modifier.isStatic(providerMethod.getModifiers())) {
+      targetObject = providerType.newInstance();
+    }
+    return (String) providerMethod.invoke(targetObject, args);
+  }
+
   private String replacePlaceholder(String sql) {
     return PropertyParser.parse(sql, configuration.getVariables());
   }

src/test/java/org/apache/ibatis/submitted/sqlprovider/SqlProviderTest.java

@@ -29,6 +29,7 @@
 import java.util.List;
 import java.util.Map;
 
+import org.apache.ibatis.annotations.Param;
 import org.apache.ibatis.annotations.SelectProvider;
 import org.apache.ibatis.builder.BuilderException;
 import org.apache.ibatis.builder.annotation.ProviderContext;
@@ -52,6 +53,7 @@ public static void setUp() throws Exception {
     Reader reader = Resources
         .getResourceAsReader("org/apache/ibatis/submitted/sqlprovider/mybatis-config.xml");
     sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
+    sqlSessionFactory.getConfiguration().addMapper(StaticMethodSqlProviderMapper.class);
     reader.close();
 
     // populate in-memory database
@@ -472,6 +474,66 @@ public void mapperMultipleParamAndProviderContext() {
     }
   }
 
+  @Test
+  public void staticMethodNoArgument() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      StaticMethodSqlProviderMapper mapper =
+          sqlSession.getMapper(StaticMethodSqlProviderMapper.class);
+      assertEquals(1, mapper.noArgument());
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
+  public void staticMethodOneArgument() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      StaticMethodSqlProviderMapper mapper =
+          sqlSession.getMapper(StaticMethodSqlProviderMapper.class);
+      assertEquals(10, mapper.oneArgument(10));
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
+  public void staticMethodMultipleArgument() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      StaticMethodSqlProviderMapper mapper =
+          sqlSession.getMapper(StaticMethodSqlProviderMapper.class);
+      assertEquals(2, mapper.multipleArgument(1, 1));
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
+  public void staticMethodOnlyProviderContext() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      StaticMethodSqlProviderMapper mapper =
+          sqlSession.getMapper(StaticMethodSqlProviderMapper.class);
+      assertEquals("onlyProviderContext", mapper.onlyProviderContext());
+    } finally {
+      sqlSession.close();
+    }
+  }
+
+  @Test
+  public void staticMethodOneArgumentAndProviderContext() {
+    SqlSession sqlSession = sqlSessionFactory.openSession();
+    try {
+      StaticMethodSqlProviderMapper mapper =
+          sqlSession.getMapper(StaticMethodSqlProviderMapper.class);
+      assertEquals("oneArgumentAndProviderContext 100", mapper.oneArgumentAndProviderContext(100));
+    } finally {
+      sqlSession.close();
+    }
+  }
+
   public interface ErrorMapper {
     @SelectProvider(type = ErrorSqlBuilder.class, method = "methodNotFound")
     void methodNotFound();
@@ -508,4 +570,48 @@ public String multipleProviderContext(ProviderContext providerContext1, Provider
     }
   }
 
+  public interface StaticMethodSqlProviderMapper {
+    @SelectProvider(type = SqlProvider.class, method = "noArgument")
+    int noArgument();
+
+    @SelectProvider(type = SqlProvider.class, method = "oneArgument")
+    int oneArgument(Integer value);
+
+    @SelectProvider(type = SqlProvider.class, method = "multipleArgument")
+    int multipleArgument(@Param("value1") Integer value1, @Param("value2") Integer value2);
+
+    @SelectProvider(type = SqlProvider.class, method = "onlyProviderContext")
+    String onlyProviderContext();
+
+    @SelectProvider(type = SqlProvider.class, method = "oneArgumentAndProviderContext")
+    String oneArgumentAndProviderContext(Integer value);
+
+    class SqlProvider {
+      public static String noArgument() {
+        return "SELECT 1 FROM INFORMATION_SCHEMA.SYSTEM_USERS";
+      }
+
+      public static String oneArgument(Integer value) {
+        return "SELECT " + value + " FROM INFORMATION_SCHEMA.SYSTEM_USERS";
+      }
+
+      public static String multipleArgument(@Param("value1") Integer value1,
+          @Param("value2") Integer value2) {
+        return "SELECT " + (value1 + value2) + " FROM INFORMATION_SCHEMA.SYSTEM_USERS";
+      }
+
+      public static String onlyProviderContext(ProviderContext context) {
+        return "SELECT '" + context.getMapperMethod().getName()
+            + "' FROM INFORMATION_SCHEMA.SYSTEM_USERS";
+      }
+
+      public static String oneArgumentAndProviderContext(Integer value, ProviderContext context) {
+        return "SELECT '" + context.getMapperMethod().getName() + " " + value
+            + "' FROM INFORMATION_SCHEMA.SYSTEM_USERS";
+      }
+
+    }
+
+  }
+
 }