Add specialized visitors for the different statements

Author: jeffgbutler

src/main/java/org/mybatis/dynamic/sql/insert/render/GeneralInsertValuePhraseVisitor.java

@@ -20,13 +20,13 @@
 
 import org.mybatis.dynamic.sql.SqlColumn;
 import org.mybatis.dynamic.sql.render.RenderingStrategy;
-import org.mybatis.dynamic.sql.util.ColumnMappingVisitor;
 import org.mybatis.dynamic.sql.util.ConstantMapping;
+import org.mybatis.dynamic.sql.util.GeneralInsertMappingVisitor;
 import org.mybatis.dynamic.sql.util.NullMapping;
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
 import org.mybatis.dynamic.sql.util.ValueMapping;
 
-public class GeneralInsertValuePhraseVisitor implements ColumnMappingVisitor<FieldAndValueAndParameters> {
+public class GeneralInsertValuePhraseVisitor implements GeneralInsertMappingVisitor<FieldAndValueAndParameters> {
 
     protected RenderingStrategy renderingStrategy;
     private AtomicInteger sequence = new AtomicInteger(1);

src/main/java/org/mybatis/dynamic/sql/insert/render/ValuePhraseVisitor.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2016-2019 the original author or authors.
+ *    Copyright 2016-2020 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.
@@ -19,13 +19,13 @@
 
 import org.mybatis.dynamic.sql.SqlColumn;
 import org.mybatis.dynamic.sql.render.RenderingStrategy;
-import org.mybatis.dynamic.sql.util.ColumnMappingVisitor;
 import org.mybatis.dynamic.sql.util.ConstantMapping;
+import org.mybatis.dynamic.sql.util.InsertMappingVisitor;
 import org.mybatis.dynamic.sql.util.NullMapping;
 import org.mybatis.dynamic.sql.util.PropertyMapping;
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
 
-public class ValuePhraseVisitor implements ColumnMappingVisitor<FieldAndValue> {
+public class ValuePhraseVisitor implements InsertMappingVisitor<FieldAndValue> {
 
     protected RenderingStrategy renderingStrategy;
 

src/main/java/org/mybatis/dynamic/sql/update/render/SetPhraseVisitor.java

@@ -24,16 +24,16 @@
 import org.mybatis.dynamic.sql.render.TableAliasCalculator;
 import org.mybatis.dynamic.sql.select.render.SelectRenderer;
 import org.mybatis.dynamic.sql.select.render.SelectStatementProvider;
-import org.mybatis.dynamic.sql.util.ColumnMappingVisitor;
 import org.mybatis.dynamic.sql.util.ColumnToColumnMapping;
 import org.mybatis.dynamic.sql.util.ConstantMapping;
 import org.mybatis.dynamic.sql.util.FragmentAndParameters;
 import org.mybatis.dynamic.sql.util.NullMapping;
 import org.mybatis.dynamic.sql.util.SelectMapping;
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
+import org.mybatis.dynamic.sql.util.UpdateMappingVisitor;
 import org.mybatis.dynamic.sql.util.ValueMapping;
 
-public class SetPhraseVisitor implements ColumnMappingVisitor<FragmentAndParameters> {
+public class SetPhraseVisitor implements UpdateMappingVisitor<FragmentAndParameters> {
 
     private AtomicInteger sequence;
     private RenderingStrategy renderingStrategy;

src/main/java/org/mybatis/dynamic/sql/util/ColumnMappingVisitor.java

@@ -1,5 +1,5 @@
 /**
- *    Copyright 2016-2019 the original author or authors.
+ *    Copyright 2016-2020 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.
@@ -21,6 +21,10 @@
  * may or may not be supported. For example, it makes no sense to map a column to another column in
  * an insert - so the ColumnToColumnMapping is only supported on update statements.
  * 
+ * Rather than implement this interface directly, we recommend implementing one of the derived
+ * interfaces. The derived interfaces encapsulate the rules about which mappings are applicable to the
+ * different types of statements.
+ * 
  * @author Jeff Butler
  *
  * @param <T> The type of object created by the visitor
@@ -32,19 +36,11 @@ public interface ColumnMappingVisitor<T> {
 
     T visit(StringConstantMapping mapping);
 
-    default <R> T visit(ValueMapping<R> mapping) {
-        throw new UnsupportedOperationException();
-    }
+    <R> T visit(ValueMapping<R> mapping);
 
-    default T visit(SelectMapping mapping) {
-        throw new UnsupportedOperationException();
-    }
+    T visit(SelectMapping mapping);
 
-    default T visit(PropertyMapping mapping) {
-        throw new UnsupportedOperationException();
-    }
+    T visit(PropertyMapping mapping);
 
-    default T visit(ColumnToColumnMapping columnMapping) {
-        throw new UnsupportedOperationException();
-    }
+    T visit(ColumnToColumnMapping columnMapping);
 }

src/main/java/org/mybatis/dynamic/sql/util/GeneralInsertMappingVisitor.java

@@ -0,0 +1,33 @@
+/**
+ *    Copyright 2016-2020 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.mybatis.dynamic.sql.util;
+
+public interface GeneralInsertMappingVisitor<T> extends ColumnMappingVisitor<T> {
+    @Override
+    default T visit(SelectMapping mapping) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    default T visit(PropertyMapping mapping) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    default T visit(ColumnToColumnMapping columnMapping) {
+        throw new UnsupportedOperationException();
+    }
+}

src/main/java/org/mybatis/dynamic/sql/util/InsertMappingVisitor.java

@@ -0,0 +1,33 @@
+/**
+ *    Copyright 2016-2020 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.mybatis.dynamic.sql.util;
+
+public interface InsertMappingVisitor<T> extends ColumnMappingVisitor<T> {
+    @Override
+    default <R> T visit(ValueMapping<R> mapping) {
+        throw new UnsupportedOperationException();
+    }
+    
+    @Override
+    default T visit(SelectMapping mapping) {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
+    default T visit(ColumnToColumnMapping columnMapping) {
+        throw new UnsupportedOperationException();
+    }
+}

src/main/java/org/mybatis/dynamic/sql/util/UpdateMappingVisitor.java

@@ -0,0 +1,23 @@
+/**
+ *    Copyright 2016-2020 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.mybatis.dynamic.sql.util;
+
+public interface UpdateMappingVisitor<T> extends ColumnMappingVisitor<T> {
+    @Override
+    default T visit(PropertyMapping mapping) {
+        throw new UnsupportedOperationException();
+    }
+}

src/test/java/org/mybatis/dynamic/sql/util/ColumnMappingVisitorTest.java

@@ -25,36 +25,63 @@
 class ColumnMappingVisitorTest {
 
     @Test
-    void testThatUnimplementedMethod1ThrowExceptions() {
+    void testThatGeneralInsertVisitorErrorsForColumnToColumnMapping() {
         TestTable table = new TestTable();
-        TestVisitor tv = new TestVisitor();
+        GeneralInsertVisitor tv = new GeneralInsertVisitor();
         ColumnToColumnMapping mapping = ColumnToColumnMapping.of(table.id, table.description);
 
         assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
     }
 
     @Test
-    void testThatUnimplementedMethod2ThrowExceptions() {
+    void testThatGeneralInsertVisitorErrorsForSelectMapping() {
         TestTable table = new TestTable();
-        TestVisitor tv = new TestVisitor();
-        ValueMapping<Integer> mapping = ValueMapping.of(table.id,  () -> 3);
+        GeneralInsertVisitor tv = new GeneralInsertVisitor();
+        SelectMapping mapping = SelectMapping.of(table.id, SqlBuilder.select(table.id).from(table));
 
         assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
     }
 
     @Test
-    void testThatUnimplementedMethod3ThrowExceptions() {
+    void testThatGeneralInsertVisitorErrorsForPropertyMapping() {
         TestTable table = new TestTable();
-        TestVisitor tv = new TestVisitor();
+        GeneralInsertVisitor tv = new GeneralInsertVisitor();
+        PropertyMapping mapping = PropertyMapping.of(table.id, "id");
+
+        assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
+    }
+    
+    @Test
+    void testThatInsertVisitorErrorsForColumnToColumnMapping() {
+        TestTable table = new TestTable();
+        InsertVisitor tv = new InsertVisitor();
+        ColumnToColumnMapping mapping = ColumnToColumnMapping.of(table.id, table.description);
+
+        assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
+    }
+
+    @Test
+    void testThatInsertVisitorErrorsForSelectMapping() {
+        TestTable table = new TestTable();
+        InsertVisitor tv = new InsertVisitor();
         SelectMapping mapping = SelectMapping.of(table.id, SqlBuilder.select(table.id).from(table));
 
         assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
     }
 
     @Test
-    void testThatUnimplementedMethod4ThrowExceptions() {
+    void testThatInsertVisitorErrorsForValueMapping() {
+        TestTable table = new TestTable();
+        InsertVisitor tv = new InsertVisitor();
+        ValueMapping<Integer> mapping = ValueMapping.of(table.id, () -> 3);
+
+        assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
+    }
+
+    @Test
+    void testThatUpdateVisitorErrorsForPropertyMapping() {
         TestTable table = new TestTable();
-        TestVisitor tv = new TestVisitor();
+        UpdateVisitor tv = new UpdateVisitor();
         PropertyMapping mapping = PropertyMapping.of(table.id, "id");
 
         assertThatExceptionOfType(UnsupportedOperationException.class).isThrownBy(() -> tv.visit(mapping));
@@ -72,7 +99,51 @@ public TestTable() {
         }
     }
 
-    private static class TestVisitor implements ColumnMappingVisitor<String> {
+    private static class GeneralInsertVisitor implements GeneralInsertMappingVisitor<String> {
+        @Override
+        public String visit(NullMapping mapping) {
+            return "Null Mapping";
+        }
+
+        @Override
+        public String visit(ConstantMapping mapping) {
+            return "Constant Mapping";
+        }
+
+        @Override
+        public String visit(StringConstantMapping mapping) {
+            return "String Constant Mapping";
+        }
+
+        @Override
+        public <R> String visit(ValueMapping<R> mapping) {
+            return "Value Mapping";
+        }
+    }
+
+    private static class InsertVisitor implements InsertMappingVisitor<String> {
+        @Override
+        public String visit(NullMapping mapping) {
+            return "Null Mapping";
+        }
+
+        @Override
+        public String visit(ConstantMapping mapping) {
+            return "Constant Mapping";
+        }
+
+        @Override
+        public String visit(StringConstantMapping mapping) {
+            return "String Constant Mapping";
+        }
+
+        @Override
+        public String visit(PropertyMapping mapping) {
+            return "Property Mapping";
+        }
+    }
+
+    private static class UpdateVisitor implements UpdateMappingVisitor<String> {
         @Override
         public String visit(NullMapping mapping) {
             return "Null Mapping";
@@ -87,5 +158,21 @@ public String visit(ConstantMapping mapping) {
         public String visit(StringConstantMapping mapping) {
             return "String Constant Mapping";
         }
+
+        @Override
+        public <R> String visit(ValueMapping<R> mapping) {
+            // TODO Auto-generated method stub
+            return null;
+        }
+
+        @Override
+        public String visit(SelectMapping mapping) {
+            return "Select Mapping";
+        }
+
+        @Override
+        public String visit(ColumnToColumnMapping columnMapping) {
+            return "Column to Column Mapping";
+        }
     }
 }