Refactor filter algorithm into base class for no value Conditions

Author: jeffgbutler

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

@@ -15,12 +15,24 @@
  */
 package org.mybatis.dynamic.sql;
 
-public abstract class AbstractNoValueCondition<T> implements VisitableCondition<T> {
+import java.util.function.BooleanSupplier;
+import java.util.function.Supplier;
+
+public abstract class AbstractNoValueCondition<T>
+        implements VisitableCondition<T> {
 
     @Override
     public <R> R accept(ConditionVisitor<T, R> visitor) {
         return visitor.visit(this);
     }
 
+    protected <S> S filter(BooleanSupplier booleanSupplier, Supplier<S> empty, S self) {
+        if (booleanSupplier.getAsBoolean()) {
+            return self;
+        } else {
+            return empty.get();
+        }
+    }
+
     public abstract String renderCondition(String columnName);
 }

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

@@ -65,12 +65,8 @@ public <S> IsNotNull<S> when(BooleanSupplier booleanSupplier) {
      *     render.
      */
     public <S> IsNotNull<S> filter(BooleanSupplier booleanSupplier) {
-        if (booleanSupplier.getAsBoolean()) {
-            @SuppressWarnings("unchecked")
-            IsNotNull<S> self = (IsNotNull<S>) this;
-            return self;
-        } else {
-            return IsNotNull.empty();
-        }
+        @SuppressWarnings("unchecked")
+        IsNotNull<S> self = (IsNotNull<S>) this;
+        return filter(booleanSupplier, IsNotNull::empty, self);
     }
 }

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

@@ -65,12 +65,8 @@ public <S> IsNull<S> when(BooleanSupplier booleanSupplier) {
      *     render.
      */
     public <S> IsNull<S> filter(BooleanSupplier booleanSupplier) {
-        if (booleanSupplier.getAsBoolean()) {
-            @SuppressWarnings("unchecked")
-            IsNull<S> self = (IsNull<S>) this;
-            return self;
-        } else {
-            return IsNull.empty();
-        }
+        @SuppressWarnings("unchecked")
+        IsNull<S> self = (IsNull<S>) this;
+        return filter(booleanSupplier, IsNull::empty, self);
     }
 }