Refactor filter/map algorithm into base class for two value Conditions

Author: jeffgbutler

src/main/java/org/mybatis/dynamic/sql/AbstractTwoValueCondition.java

@@ -15,7 +15,12 @@
  */
 package org.mybatis.dynamic.sql;
 
-public abstract class AbstractTwoValueCondition<T> implements VisitableCondition<T> {
+import java.util.function.BiFunction;
+import java.util.function.BiPredicate;
+import java.util.function.UnaryOperator;
+
+public abstract class AbstractTwoValueCondition<T, S extends AbstractTwoValueCondition<T, S>>
+        implements VisitableCondition<T> {
     protected final T value1;
     protected final T value2;
 
@@ -37,5 +42,42 @@ public <R> R accept(ConditionVisitor<T, R> visitor) {
         return visitor.visit(this);
     }
 
+    protected S filter(BiPredicate<T, T> predicate, S self, S empty) {
+        if (shouldRender()) {
+            return predicate.test(value1, value2) ? self : empty;
+        } else {
+            return self;
+        }
+    }
+
+    protected S map(UnaryOperator<T> mapper1, UnaryOperator<T> mapper2, S self, BiFunction<T, T, S> constructor) {
+        if (shouldRender()) {
+            return constructor.apply(mapper1.apply(value1), mapper2.apply(value2));
+        }else {
+            return self;
+        }
+    }
+
+    /**
+     * If renderable and the values match the predicate, returns this condition. Else returns a condition
+     *     that will not render.
+     *
+     * @param predicate predicate applied to the values, if renderable
+     * @return this condition if renderable and the values match the predicate, otherwise a condition
+     *     that will not render.
+     */
+    public abstract S filter(BiPredicate<T, T> predicate);
+
+    /**
+     * If renderable, apply the mappings to the values and return a new condition with the new values. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper1 a mapping function to apply to the first value, if renderable
+     * @param mapper2 a mapping function to apply to the second value, if renderable
+     * @return a new condition with the result of applying the mappers to the values of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public abstract S map(UnaryOperator<T> mapper1, UnaryOperator<T> mapper2);
+
     public abstract String renderCondition(String columnName, String placeholder1, String placeholder2);
 }

src/main/java/org/mybatis/dynamic/sql/ConditionVisitor.java

@@ -22,7 +22,7 @@ public interface ConditionVisitor<T, R> {
 
     R visit(AbstractSingleValueCondition<T> condition);
 
-    R visit(AbstractTwoValueCondition<T> condition);
+    R visit(AbstractTwoValueCondition<T, ?> condition);
 
     R visit(AbstractSubselectCondition<T> condition);
 

src/main/java/org/mybatis/dynamic/sql/where/condition/IsBetween.java

@@ -21,7 +21,7 @@
 import org.mybatis.dynamic.sql.AbstractTwoValueCondition;
 import org.mybatis.dynamic.sql.util.Predicates;
 
-public class IsBetween<T> extends AbstractTwoValueCondition<T> {
+public class IsBetween<T> extends AbstractTwoValueCondition<T, IsBetween<T>> {
 
     protected IsBetween(T value1, T value2) {
         super(value1, value2);
@@ -61,33 +61,14 @@ public IsBetween<T> then(UnaryOperator<T> mapper1, UnaryOperator<T> mapper2) {
         return map(mapper1, mapper2);
     }
 
-    /**
-     * If renderable and the values match the predicate, returns this condition. Else returns a condition
-     *     that will not render.
-     *
-     * @param predicate predicate applied to the values, if renderable
-     * @return this condition if renderable and the values match the predicate, otherwise a condition
-     *     that will not render.
-     */
+    @Override
     public IsBetween<T> filter(BiPredicate<T, T> predicate) {
-        if (shouldRender()) {
-            return predicate.test(value1, value2) ? this : EmptyIsBetween.empty();
-        } else {
-            return this;
-        }
+        return filter(predicate, this, EmptyIsBetween.empty());
     }
 
-    /**
-     * If renderable, apply the mappings to the values and return a new condition with the new values. Else return a
-     *     condition that will not render (this).
-     *
-     * @param mapper1 a mapping function to apply to the first value, if renderable
-     * @param mapper2 a mapping function to apply to the second value, if renderable
-     * @return a new condition with the result of applying the mappers to the values of this condition,
-     *     if renderable, otherwise a condition that will not render.
-     */
+    @Override
     public IsBetween<T> map(UnaryOperator<T> mapper1, UnaryOperator<T> mapper2) {
-        return shouldRender() ? new IsBetween<>(mapper1.apply(value1), mapper2.apply(value2)) : this;
+        return map(mapper1, mapper2, this, IsBetween::new);
     }
 
     public static <T> Builder<T> isBetween(T value1) {

src/main/java/org/mybatis/dynamic/sql/where/condition/IsNotBetween.java

@@ -21,7 +21,7 @@
 import org.mybatis.dynamic.sql.AbstractTwoValueCondition;
 import org.mybatis.dynamic.sql.util.Predicates;
 
-public class IsNotBetween<T> extends AbstractTwoValueCondition<T> {
+public class IsNotBetween<T> extends AbstractTwoValueCondition<T, IsNotBetween<T>> {
 
     protected IsNotBetween(T value1, T value2) {
         super(value1, value2);
@@ -61,33 +61,14 @@ public IsNotBetween<T> then(UnaryOperator<T> mapper1, UnaryOperator<T> mapper2)
         return map(mapper1, mapper2);
     }
 
-    /**
-     * If renderable and the values match the predicate, returns this condition. Else returns a condition
-     *     that will not render.
-     *
-     * @param predicate predicate applied to the values, if renderable
-     * @return this condition if renderable and the values match the predicate, otherwise a condition
-     *     that will not render.
-     */
+    @Override
     public IsNotBetween<T> filter(BiPredicate<T, T> predicate) {
-        if (shouldRender()) {
-            return predicate.test(value1, value2) ? this : EmptyIsNotBetween.empty();
-        } else {
-            return this;
-        }
+        return filter(predicate, this, EmptyIsNotBetween.empty());
     }
 
-    /**
-     * If renderable, apply the mappings to the values and return a new condition with the new values. Else return a
-     *     condition that will not render (this).
-     *
-     * @param mapper1 a mapping function to apply to the first value, if renderable
-     * @param mapper2 a mapping function to apply to the second value, if renderable
-     * @return a new condition with the result of applying the mappers to the values of this condition,
-     *     if renderable, otherwise a condition that will not render.
-     */
+    @Override
     public IsNotBetween<T> map(UnaryOperator<T> mapper1, UnaryOperator<T> mapper2) {
-        return shouldRender() ? new IsNotBetween<>(mapper1.apply(value1), mapper2.apply(value2)) : this;
+        return map(mapper1, mapper2, this, IsNotBetween::new);
     }
 
     public static <T> Builder<T> isNotBetween(T value1) {

src/main/java/org/mybatis/dynamic/sql/where/render/WhereConditionVisitor.java

@@ -77,7 +77,7 @@ public FragmentAndParameters visit(AbstractSingleValueCondition<T> condition) {
     }
 
     @Override
-    public FragmentAndParameters visit(AbstractTwoValueCondition<T> condition) {
+    public FragmentAndParameters visit(AbstractTwoValueCondition<T, ?> condition) {
         String mapKey1 = RenderingStrategy.formatParameterMapKey(sequence);
         String mapKey2 = RenderingStrategy.formatParameterMapKey(sequence);
         String fragment = condition.renderCondition(columnName(),