Map functions can change data types - Single Value Conditions

Author: jeffgbutler

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

@@ -18,10 +18,8 @@
 import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
-import java.util.function.UnaryOperator;
 
-public abstract class AbstractSingleValueCondition<T, S extends AbstractSingleValueCondition<T, S>>
-        implements VisitableCondition<T> {
+public abstract class AbstractSingleValueCondition<T> implements VisitableCondition<T> {
     protected final T value;
 
     protected AbstractSingleValueCondition(T value) {
@@ -37,41 +35,32 @@ public <R> R accept(ConditionVisitor<T, R> visitor) {
         return visitor.visit(this);
     }
 
-    protected S filter(Predicate<T> predicate, Supplier<S> empty, S self) {
+    protected <S> S filterSupport(Predicate<? super T> predicate, Supplier<S> empty, S self) {
         if (shouldRender()) {
             return predicate.test(value) ? self : empty.get();
         } else {
             return self;
         }
     }
 
-    /**
-     * If renderable and the value matches the predicate, returns this condition. Else returns a condition
-     *     that will not render.
-     *
-     * @param predicate predicate applied to the value, if renderable
-     * @return this condition if renderable and the value matches the predicate, otherwise a condition
-     *     that will not render.
-     */
-    public abstract S filter(Predicate<T> predicate);
-
-    protected S map(UnaryOperator<T> mapper, Function<T, S> constructor, S self) {
+    protected <R, S> S mapSupport(Function<? super T, ? extends R> mapper, Function<R, S> constructor,
+            Supplier<S> empty) {
         if (shouldRender()) {
             return constructor.apply(mapper.apply(value));
         } else {
-            return self;
+            return empty.get();
         }
     }
 
     /**
-     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
-     *     condition that will not render (this).
+     * If renderable and the value matches the predicate, returns this condition. Else returns a condition
+     *     that will not render.
      *
-     * @param mapper a mapping function to apply to the value, if renderable
-     * @return a new condition with the result of applying the mapper to the value of this condition,
-     *     if renderable, otherwise a condition that will not render.
+     * @param predicate predicate applied to the value, if renderable
+     * @return this condition if renderable and the value matches the predicate, otherwise a condition
+     *     that will not render.
      */
-    public abstract S map(UnaryOperator<T> mapper);
+    public abstract AbstractSingleValueCondition<T> filter(Predicate<? super T> predicate);
 
     public abstract String renderCondition(String columnName, String placeholder);
 }

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

@@ -20,7 +20,7 @@ public interface ConditionVisitor<T, R> {
 
     R visit(AbstractNoValueCondition<T> condition);
 
-    R visit(AbstractSingleValueCondition<T, ?> condition);
+    R visit(AbstractSingleValueCondition<T> condition);
 
     R visit(AbstractTwoValueCondition<T, ?> condition);
 

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

@@ -15,12 +15,13 @@
  */
 package org.mybatis.dynamic.sql.where.condition;
 
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsEqualTo<T> extends AbstractSingleValueCondition<T, IsEqualTo<T>> {
+public class IsEqualTo<T> extends AbstractSingleValueCondition<T> {
 
     private static final IsEqualTo<?> EMPTY = new IsEqualTo<Object>(null) {
         @Override
@@ -66,7 +67,7 @@ public IsEqualTo<T> when(Predicate<T> predicate) {
      * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
      *     condition that will not render (this).
      *
-     * @deprecated replaced by {@link IsEqualTo#map(UnaryOperator)}
+     * @deprecated replaced by {@link IsEqualTo#map(Function)}
      * @param mapper a mapping function to apply to the value, if renderable
      * @return a new condition with the result of applying the mapper to the value of this condition,
      *     if renderable, otherwise a condition that will not render.
@@ -77,12 +78,20 @@ public IsEqualTo<T> then(UnaryOperator<T> mapper) {
     }
 
     @Override
-    public IsEqualTo<T> filter(Predicate<T> predicate) {
-        return filter(predicate, IsEqualTo::empty, this);
+    public IsEqualTo<T> filter(Predicate<? super T> predicate) {
+        return filterSupport(predicate, IsEqualTo::empty, this);
     }
 
-    @Override
-    public IsEqualTo<T> map(UnaryOperator<T> mapper) {
-        return map(mapper, IsEqualTo::new, this);
+    /**
+     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper a mapping function to apply to the value, if renderable
+     * @param <R> type of the new condition
+     * @return a new condition with the result of applying the mapper to the value of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public <R> IsEqualTo<R> map(Function<? super T, ? extends R> mapper) {
+        return mapSupport(mapper, IsEqualTo::new, IsEqualTo::empty);
     }
 }

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

@@ -15,12 +15,13 @@
  */
 package org.mybatis.dynamic.sql.where.condition;
 
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsGreaterThan<T> extends AbstractSingleValueCondition<T, IsGreaterThan<T>> {
+public class IsGreaterThan<T> extends AbstractSingleValueCondition<T> {
     private static final IsGreaterThan<?> EMPTY = new IsGreaterThan<Object>(null) {
         @Override
         public boolean shouldRender() {
@@ -65,7 +66,7 @@ public IsGreaterThan<T> when(Predicate<T> predicate) {
      * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
      *     condition that will not render (this).
      *
-     * @deprecated replaced by {@link IsGreaterThan#map(UnaryOperator)}
+     * @deprecated replaced by {@link IsGreaterThan#map(Function)}
      * @param mapper a mapping function to apply to the value, if renderable
      * @return a new condition with the result of applying the mapper to the value of this condition,
      *     if renderable, otherwise a condition that will not render.
@@ -76,12 +77,20 @@ public IsGreaterThan<T> then(UnaryOperator<T> mapper) {
     }
 
     @Override
-    public IsGreaterThan<T> filter(Predicate<T> predicate) {
-        return filter(predicate, IsGreaterThan::empty, this);
+    public IsGreaterThan<T> filter(Predicate<? super T> predicate) {
+        return filterSupport(predicate, IsGreaterThan::empty, this);
     }
 
-    @Override
-    public IsGreaterThan<T> map(UnaryOperator<T> mapper) {
-        return map(mapper, IsGreaterThan::new, this);
+    /**
+     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper a mapping function to apply to the value, if renderable
+     * @param <R> type of the new condition
+     * @return a new condition with the result of applying the mapper to the value of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public <R> IsGreaterThan<R> map(Function<? super T, ? extends R> mapper) {
+        return mapSupport(mapper, IsGreaterThan::new, IsGreaterThan::empty);
     }
 }

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

@@ -15,12 +15,13 @@
  */
 package org.mybatis.dynamic.sql.where.condition;
 
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsGreaterThanOrEqualTo<T> extends AbstractSingleValueCondition<T, IsGreaterThanOrEqualTo<T>> {
+public class IsGreaterThanOrEqualTo<T> extends AbstractSingleValueCondition<T> {
     private static final IsGreaterThanOrEqualTo<?> EMPTY = new IsGreaterThanOrEqualTo<Object>(null) {
         @Override
         public boolean shouldRender() {
@@ -65,7 +66,7 @@ public IsGreaterThanOrEqualTo<T> when(Predicate<T> predicate) {
      * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
      *     condition that will not render (this).
      *
-     * @deprecated replaced by {@link IsGreaterThanOrEqualTo#map(UnaryOperator)}
+     * @deprecated replaced by {@link IsGreaterThanOrEqualTo#map(Function)}
      * @param mapper a mapping function to apply to the value, if renderable
      * @return a new condition with the result of applying the mapper to the value of this condition,
      *     if renderable, otherwise a condition that will not render.
@@ -76,12 +77,20 @@ public IsGreaterThanOrEqualTo<T> then(UnaryOperator<T> mapper) {
     }
 
     @Override
-    public IsGreaterThanOrEqualTo<T> filter(Predicate<T> predicate) {
-        return filter(predicate, IsGreaterThanOrEqualTo::empty, this);
+    public IsGreaterThanOrEqualTo<T> filter(Predicate<? super T> predicate) {
+        return filterSupport(predicate, IsGreaterThanOrEqualTo::empty, this);
     }
 
-    @Override
-    public IsGreaterThanOrEqualTo<T> map(UnaryOperator<T> mapper) {
-        return map(mapper, IsGreaterThanOrEqualTo::new, this);
+    /**
+     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper a mapping function to apply to the value, if renderable
+     * @param <R> type of the new condition
+     * @return a new condition with the result of applying the mapper to the value of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public <R> IsGreaterThanOrEqualTo<R> map(Function<? super T, ? extends R> mapper) {
+        return mapSupport(mapper, IsGreaterThanOrEqualTo::new, IsGreaterThanOrEqualTo::empty);
     }
 }

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

@@ -15,12 +15,13 @@
  */
 package org.mybatis.dynamic.sql.where.condition;
 
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsLessThan<T> extends AbstractSingleValueCondition<T, IsLessThan<T>> {
+public class IsLessThan<T> extends AbstractSingleValueCondition<T> {
     private static final IsLessThan<?> EMPTY = new IsLessThan<Object>(null) {
         @Override
         public boolean shouldRender() {
@@ -65,7 +66,7 @@ public IsLessThan<T> when(Predicate<T> predicate) {
      * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
      *     condition that will not render (this).
      *
-     * @deprecated replaced by {@link IsLessThan#map(UnaryOperator)}
+     * @deprecated replaced by {@link IsLessThan#map(Function)}
      * @param mapper a mapping function to apply to the value, if renderable
      * @return a new condition with the result of applying the mapper to the value of this condition,
      *     if renderable, otherwise a condition that will not render.
@@ -76,12 +77,20 @@ public IsLessThan<T> then(UnaryOperator<T> mapper) {
     }
 
     @Override
-    public IsLessThan<T> filter(Predicate<T> predicate) {
-        return filter(predicate, IsLessThan::empty, this);
+    public IsLessThan<T> filter(Predicate<? super T> predicate) {
+        return filterSupport(predicate, IsLessThan::empty, this);
     }
 
-    @Override
-    public IsLessThan<T> map(UnaryOperator<T> mapper) {
-        return map(mapper, IsLessThan::new, this);
+    /**
+     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper a mapping function to apply to the value, if renderable
+     * @param <R> type of the new condition
+     * @return a new condition with the result of applying the mapper to the value of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public <R> IsLessThan<R> map(Function<? super T, ? extends R> mapper) {
+        return mapSupport(mapper, IsLessThan::new, IsLessThan::empty);
     }
 }

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

@@ -15,12 +15,13 @@
  */
 package org.mybatis.dynamic.sql.where.condition;
 
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsLessThanOrEqualTo<T> extends AbstractSingleValueCondition<T, IsLessThanOrEqualTo<T>> {
+public class IsLessThanOrEqualTo<T> extends AbstractSingleValueCondition<T> {
     private static final IsLessThanOrEqualTo<?> EMPTY = new IsLessThanOrEqualTo<Object>(null) {
         @Override
         public boolean shouldRender() {
@@ -65,7 +66,7 @@ public IsLessThanOrEqualTo<T> when(Predicate<T> predicate) {
      * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
      *     condition that will not render (this).
      *
-     * @deprecated replaced by {@link IsLessThanOrEqualTo#map(UnaryOperator)}
+     * @deprecated replaced by {@link IsLessThanOrEqualTo#map(Function)}
      * @param mapper a mapping function to apply to the value, if renderable
      * @return a new condition with the result of applying the mapper to the value of this condition,
      *     if renderable, otherwise a condition that will not render.
@@ -76,12 +77,20 @@ public IsLessThanOrEqualTo<T> then(UnaryOperator<T> mapper) {
     }
 
     @Override
-    public IsLessThanOrEqualTo<T> filter(Predicate<T> predicate) {
-        return filter(predicate, IsLessThanOrEqualTo::empty, this);
+    public IsLessThanOrEqualTo<T> filter(Predicate<? super T> predicate) {
+        return filterSupport(predicate, IsLessThanOrEqualTo::empty, this);
     }
 
-    @Override
-    public IsLessThanOrEqualTo<T> map(UnaryOperator<T> mapper) {
-        return map(mapper, IsLessThanOrEqualTo::new, this);
+    /**
+     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper a mapping function to apply to the value, if renderable
+     * @param <R> type of the new condition
+     * @return a new condition with the result of applying the mapper to the value of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public <R> IsLessThanOrEqualTo<R> map(Function<? super T, ? extends R> mapper) {
+        return mapSupport(mapper, IsLessThanOrEqualTo::new, IsLessThanOrEqualTo::empty);
     }
 }

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

@@ -15,12 +15,13 @@
  */
 package org.mybatis.dynamic.sql.where.condition;
 
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.UnaryOperator;
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsLike<T> extends AbstractSingleValueCondition<T, IsLike<T>> {
+public class IsLike<T> extends AbstractSingleValueCondition<T> {
     private static final IsLike<?> EMPTY = new IsLike<Object>(null) {
         @Override
         public boolean shouldRender() {
@@ -65,7 +66,7 @@ public IsLike<T> when(Predicate<T> predicate) {
      * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
      *     condition that will not render (this).
      *
-     * @deprecated replaced by {@link IsLike#map(UnaryOperator)}
+     * @deprecated replaced by {@link IsLike#map(Function)}
      * @param mapper a mapping function to apply to the value, if renderable
      * @return a new condition with the result of applying the mapper to the value of this condition,
      *     if renderable, otherwise a condition that will not render.
@@ -76,12 +77,20 @@ public IsLike<T> then(UnaryOperator<T> mapper) {
     }
 
     @Override
-    public IsLike<T> filter(Predicate<T> predicate) {
-        return filter(predicate, IsLike::empty, this);
+    public IsLike<T> filter(Predicate<? super T> predicate) {
+        return filterSupport(predicate, IsLike::empty, this);
     }
 
-    @Override
-    public IsLike<T> map(UnaryOperator<T> mapper) {
-        return map(mapper, IsLike::new, this);
+    /**
+     * If renderable, apply the mapping to the value and return a new condition with the new value. Else return a
+     *     condition that will not render (this).
+     *
+     * @param mapper a mapping function to apply to the value, if renderable
+     * @param <R> type of the new condition
+     * @return a new condition with the result of applying the mapper to the value of this condition,
+     *     if renderable, otherwise a condition that will not render.
+     */
+    public <R> IsLike<R> map(Function<? super T, ? extends R> mapper) {
+        return mapSupport(mapper, IsLike::new, IsLike::empty);
     }
 }