Make filter and map optional on single value conditions

Author: jeffgbutler

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

@@ -54,27 +54,6 @@ protected <R, S extends AbstractSingleValueCondition<R>> S mapSupport(Function<?
         }
     }
 
-    /**
-     * 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 AbstractSingleValueCondition<T> filter(Predicate<? super 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).
-     *
-     * @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 abstract <R> AbstractSingleValueCondition<R> map(Function<? super T, ? extends R> mapper);
-
     public abstract String operator();
 
     @Override
@@ -86,4 +65,54 @@ public FragmentAndParameters renderCondition(RenderingContext renderingContext,
                 .withParameter(parameterInfo.parameterMapKey(), leftColumn.convertParameterType(value()))
                 .build();
     }
+
+    /**
+     * Conditions may implement Filterable to add optionality to rendering.
+     *
+     * <p>If a condition is Filterable, then a user may add a filter to the usage of the condition that makes a decision
+     * whether to render the condition at runtime. Conditions that fail the filter will be dropped from the
+     * rendered SQL.
+     *
+     * <p>Implementations of Filterable may call
+     * {@link AbstractSingleValueCondition#filterSupport(Predicate, Supplier, AbstractSingleValueCondition)} as
+     * a common implementation of the filtering algorithm.
+     *
+     * @param <T> the Java type related to the database column type
+     */
+    public interface Filterable<T> {
+        /**
+         * 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.
+         */
+        AbstractSingleValueCondition<T> filter(Predicate<? super T> predicate);
+    }
+
+    /**
+     * Conditions may implement Mappable to alter condition values or types during rendering.
+     *
+     * <p>If a condition is Mappable, then a user may add a mapper to the usage of the condition that can alter the
+     * values of a condition, or change that datatype.
+     *
+     * <p>Implementations of Mappable may call
+     * {@link AbstractSingleValueCondition#mapSupport(Function, Function, Supplier)} as
+     * a common implementation of the mapping algorithm.
+     *
+     * @param <T> the Java type related to the database column type
+     */
+    public interface Mappable<T> {
+        /**
+         * 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.
+         */
+        <R> AbstractSingleValueCondition<R> map(Function<? super T, ? extends R> mapper);
+    }
 }

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

@@ -21,7 +21,8 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsEqualTo<T> extends AbstractSingleValueCondition<T> {
+public class IsEqualTo<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
 
     private static final IsEqualTo<?> EMPTY = new IsEqualTo<Object>(-1) {
         @Override

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

@@ -21,7 +21,8 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsGreaterThan<T> extends AbstractSingleValueCondition<T> {
+public class IsGreaterThan<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
     private static final IsGreaterThan<?> EMPTY = new IsGreaterThan<Object>(-1) {
         @Override
         public Object value() {

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

@@ -21,7 +21,8 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsGreaterThanOrEqualTo<T> extends AbstractSingleValueCondition<T> {
+public class IsGreaterThanOrEqualTo<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
     private static final IsGreaterThanOrEqualTo<?> EMPTY = new IsGreaterThanOrEqualTo<Object>(-1) {
         @Override
         public Object value() {

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

@@ -21,7 +21,9 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsLessThan<T> extends AbstractSingleValueCondition<T> {
+public class IsLessThan<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
+
     private static final IsLessThan<?> EMPTY = new IsLessThan<Object>(-1) {
         @Override
         public Object value() {

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

@@ -21,7 +21,8 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsLessThanOrEqualTo<T> extends AbstractSingleValueCondition<T> {
+public class IsLessThanOrEqualTo<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
     private static final IsLessThanOrEqualTo<?> EMPTY = new IsLessThanOrEqualTo<Object>(-1) {
         @Override
         public Object value() {

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

@@ -21,7 +21,9 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsLike<T> extends AbstractSingleValueCondition<T> {
+public class IsLike<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
+
     private static final IsLike<?> EMPTY = new IsLike<Object>(-1) {
         @Override
         public Object value() {

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

@@ -23,7 +23,8 @@
 import org.mybatis.dynamic.sql.util.StringUtilities;
 
 public class IsLikeCaseInsensitive<T> extends AbstractSingleValueCondition<T>
-        implements CaseInsensitiveRenderableCondition<T> {
+        implements CaseInsensitiveRenderableCondition<T>, AbstractSingleValueCondition.Filterable<T>,
+        AbstractSingleValueCondition.Mappable<T> {
     private static final IsLikeCaseInsensitive<?> EMPTY = new IsLikeCaseInsensitive<>("") { //$NON-NLS-1$
         @Override
         public String value() {

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

@@ -21,7 +21,8 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsNotEqualTo<T> extends AbstractSingleValueCondition<T> {
+public class IsNotEqualTo<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
     private static final IsNotEqualTo<?> EMPTY = new IsNotEqualTo<Object>(-1) {
         @Override
         public Object value() {

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

@@ -21,7 +21,8 @@
 
 import org.mybatis.dynamic.sql.AbstractSingleValueCondition;
 
-public class IsNotLike<T> extends AbstractSingleValueCondition<T> {
+public class IsNotLike<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
     private static final IsNotLike<?> EMPTY = new IsNotLike<Object>(-1) {
         @Override
         public Object value() {

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

@@ -23,7 +23,8 @@
 import org.mybatis.dynamic.sql.util.StringUtilities;
 
 public class IsNotLikeCaseInsensitive<T> extends AbstractSingleValueCondition<T>
-        implements CaseInsensitiveRenderableCondition<T> {
+        implements CaseInsensitiveRenderableCondition<T>, AbstractSingleValueCondition.Filterable<T>,
+        AbstractSingleValueCondition.Mappable<T> {
     private static final IsNotLikeCaseInsensitive<?> EMPTY = new IsNotLikeCaseInsensitive<>("") { //$NON-NLS-1$
         @Override
         public String value() {
@@ -56,16 +57,7 @@ public IsNotLikeCaseInsensitive<T> filter(Predicate<? super T> predicate) {
         return filterSupport(predicate, IsNotLikeCaseInsensitive::empty, 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
-     *
-     * @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.
-     */
+    @Override
     public <R> IsNotLikeCaseInsensitive<R> map(Function<? super T, ? extends R> mapper) {
         return mapSupport(mapper, IsNotLikeCaseInsensitive::new, IsNotLikeCaseInsensitive::empty);
     }

src/test/java/examples/mysql/IsLikeEscape.java

@@ -27,7 +27,8 @@
 import org.mybatis.dynamic.sql.util.FragmentAndParameters;
 
 @NullMarked
-public class IsLikeEscape<T> extends AbstractSingleValueCondition<T> {
+public class IsLikeEscape<T> extends AbstractSingleValueCondition<T>
+        implements AbstractSingleValueCondition.Filterable<T>, AbstractSingleValueCondition.Mappable<T> {
     private static final IsLikeEscape<?> EMPTY = new IsLikeEscape<Object>(-1, null) {
         @Override
         public Object value() {

src/test/kotlin/examples/kotlin/mybatis3/mariadb/KIsLikeEscape.kt

@@ -10,7 +10,8 @@ import org.mybatis.dynamic.sql.util.FragmentAndParameters
 sealed class KIsLikeEscape<T : Any>(
     value: T,
     private val escapeCharacter: Char? = null
-) : AbstractSingleValueCondition<T>(value) {
+) : AbstractSingleValueCondition<T>(value), AbstractSingleValueCondition.Filterable<T>,
+    AbstractSingleValueCondition.Mappable<T> {
 
     override fun operator(): String = "like"