Start of support for Value or Null Mapping

Author: jeffgbutler

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 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.
@@ -26,6 +26,7 @@
 import org.mybatis.dynamic.sql.util.NullMapping;
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
 import org.mybatis.dynamic.sql.util.ValueMapping;
+import org.mybatis.dynamic.sql.util.ValueOrNullMapping;
 import org.mybatis.dynamic.sql.util.ValueWhenPresentMapping;
 
 public class GeneralInsertValuePhraseVisitor extends GeneralInsertMappingVisitor<Optional<FieldAndValueAndParameters>> {
@@ -39,9 +40,7 @@ public GeneralInsertValuePhraseVisitor(RenderingStrategy renderingStrategy) {
 
     @Override
     public Optional<FieldAndValueAndParameters> visit(NullMapping mapping) {
-        return FieldAndValueAndParameters.withFieldName(mapping.columnName())
-                .withValuePhrase("null") //$NON-NLS-1$
-                .buildOptional();
+        return buildNullFragment(mapping);
     }
 
     @Override
@@ -63,6 +62,12 @@ public <T> Optional<FieldAndValueAndParameters> visit(ValueMapping<T> mapping) {
         return buildValueFragment(mapping, mapping.value());
     }
 
+    @Override
+    public <T> Optional<FieldAndValueAndParameters> visit(ValueOrNullMapping<T> mapping) {
+        return mapping.value().map(v -> buildValueFragment(mapping, v))
+                .orElseGet(() -> buildNullFragment(mapping));
+    }
+
     @Override
     public <T> Optional<FieldAndValueAndParameters> visit(ValueWhenPresentMapping<T> mapping) {
         return mapping.value().flatMap(v -> buildValueFragment(mapping, v));
@@ -73,6 +78,12 @@ private Optional<FieldAndValueAndParameters> buildValueFragment(AbstractColumnMa
         return buildFragment(mapping, value);
     }
 
+    private Optional<FieldAndValueAndParameters> buildNullFragment(AbstractColumnMapping mapping) {
+        return FieldAndValueAndParameters.withFieldName(mapping.columnName())
+                .withValuePhrase("null") //$NON-NLS-1$
+                .buildOptional();
+    }
+
     private Optional<FieldAndValueAndParameters> buildFragment(AbstractColumnMapping mapping, Object value) {
         String mapKey = RenderingStrategy.formatParameterMapKey(sequence);
 

src/main/java/org/mybatis/dynamic/sql/update/UpdateDSL.java

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 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.
@@ -34,6 +34,7 @@
 import org.mybatis.dynamic.sql.util.SelectMapping;
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
 import org.mybatis.dynamic.sql.util.ValueMapping;
+import org.mybatis.dynamic.sql.util.ValueOrNullMapping;
 import org.mybatis.dynamic.sql.util.ValueWhenPresentMapping;
 import org.mybatis.dynamic.sql.where.AbstractWhereDSL;
 import org.mybatis.dynamic.sql.where.AbstractWhereSupport;
@@ -126,6 +127,15 @@ public UpdateDSL<R> equalTo(BasicColumn rightColumn) {
             return UpdateDSL.this;
         }
 
+        public UpdateDSL<R> equalToOrNull(T value) {
+            return equalToOrNull(() -> value);
+        }
+
+        public UpdateDSL<R> equalToOrNull(Supplier<T> valueSupplier) {
+            columnMappings.add(ValueOrNullMapping.of(column, valueSupplier));
+            return UpdateDSL.this;
+        }
+
         public UpdateDSL<R> equalToWhenPresent(T value) {
             return equalToWhenPresent(() -> value);
         }

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 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.
@@ -33,6 +33,7 @@
 import org.mybatis.dynamic.sql.util.StringConstantMapping;
 import org.mybatis.dynamic.sql.util.UpdateMappingVisitor;
 import org.mybatis.dynamic.sql.util.ValueMapping;
+import org.mybatis.dynamic.sql.util.ValueOrNullMapping;
 import org.mybatis.dynamic.sql.util.ValueWhenPresentMapping;
 
 public class SetPhraseVisitor extends UpdateMappingVisitor<Optional<FragmentAndParameters>> {
@@ -74,6 +75,16 @@ public <T> Optional<FragmentAndParameters> visit(ValueMapping<T> mapping) {
         return buildFragment(mapping, mapping.value());
     }
 
+    @Override
+    public <T> Optional<FragmentAndParameters> visit(ValueOrNullMapping<T> mapping) {
+        return mapping.value()
+                .map(v -> buildFragment(mapping, v))
+                .orElseGet(() -> FragmentAndParameters
+                        .withFragment(mapping.columnName() + " = null") //$NON-NLS-1$
+                        .buildOptional()
+                );
+    }
+
     @Override
     public <T> Optional<FragmentAndParameters> visit(ValueWhenPresentMapping<T> mapping) {
         return mapping.value().flatMap(v -> buildFragment(mapping, v));

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 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.
@@ -38,6 +38,8 @@ public interface ColumnMappingVisitor<R> {
 
     <T> R visit(ValueMapping<T> mapping);
 
+    <T> R visit(ValueOrNullMapping<T> mapping);
+
     <T> R visit(ValueWhenPresentMapping<T> mapping);
 
     R visit(SelectMapping mapping);

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 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 +21,11 @@ public final <T> R visit(ValueMapping<T> mapping) {
         throw new UnsupportedOperationException();
     }
 
+    @Override
+    public final <T> R visit(ValueOrNullMapping<T> mapping) {
+        throw new UnsupportedOperationException();
+    }
+
     @Override
     public final <T> R visit(ValueWhenPresentMapping<T> mapping) {
         throw new UnsupportedOperationException();

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

@@ -0,0 +1,48 @@
+/*
+ *    Copyright 2016-2021 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;
+
+import org.mybatis.dynamic.sql.SqlColumn;
+
+import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Supplier;
+
+public class ValueOrNullMapping<T> extends AbstractColumnMapping {
+
+    private final Supplier<T> valueSupplier;
+    // keep a reference to the column so we don't lose the type
+    private final SqlColumn<T> localColumn;
+
+    private ValueOrNullMapping(SqlColumn<T> column, Supplier<T> valueSupplier) {
+        super(column);
+        this.valueSupplier = Objects.requireNonNull(valueSupplier);
+        localColumn = Objects.requireNonNull(column);
+    }
+
+    public Optional<Object> value() {
+        return Optional.ofNullable(localColumn.convertParameterType(valueSupplier.get()));
+    }
+
+    @Override
+    public <R> R accept(ColumnMappingVisitor<R> visitor) {
+        return visitor.visit(this);
+    }
+
+    public static <T> ValueOrNullMapping<T> of(SqlColumn<T> column, Supplier<T> valueSupplier) {
+        return new ValueOrNullMapping<>(column, valueSupplier);
+    }
+}

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

@@ -1,5 +1,5 @@
 /*
- *    Copyright 2016-2020 the original author or authors.
+ *    Copyright 2016-2021 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.
@@ -192,6 +192,11 @@ public <R> String visit(ValueMapping<R> mapping) {
             return "Value Mapping";
         }
 
+        @Override
+        public <R> String visit(ValueOrNullMapping<R> mapping) {
+            return "Value or Null Mapping";
+        }
+
         @Override
         public <R> String visit(ValueWhenPresentMapping<R> mapping) {
             return "Value When Present Mapping";
@@ -246,6 +251,11 @@ public <R> String visit(ValueMapping<R> mapping) {
             return "Value Mapping";
         }
 
+        @Override
+        public <R> String visit(ValueOrNullMapping<R> mapping) {
+            return "Value or Null Mapping";
+        }
+
         @Override
         public <R> String visit(ValueWhenPresentMapping<R> mapping) {
             return "Value When Present Mapping";