Value: secondary clauses now use Supplier's to enable short circuiting

README.adoc

@@ -59,7 +59,7 @@ if (isTrue() && isAlsoTrue()) {
 [[source,java]]
 ----
 Condition.where(isTrue())
-         .and(isAlsoTrue())
+         .and(() -> isAlsoTrue())
          .then(() -> doSomething())
          .otherwise(() -> doSomethingElse());
 ----
@@ -78,7 +78,7 @@ if (isTrue() || alternativeIsTrue()) {
 [[source,java]]
 ----
 Condition.where(isTrue())
-         .or(alternativeIsTrue())
+         .or(() -> alternativeIsTrue())
          .then(() -> doSomething())
          .otherwise(() -> doSomethingElse());
 ----
@@ -115,7 +115,7 @@ if (isTrue() || !isFalse()) {
 [[source,java]]
 ----
 Condition.where(isTrue())
-         .andNot(isFalse())
+         .andNot(() -> isFalse())
          .then(() -> doSomething())
          .otherwise(() -> doSomethingElse());
 ----
@@ -134,7 +134,7 @@ if (isFalse() || !isAlsoFalse()) {
 [[source,java]]
 ----
 Condition.where(isFalse())
-         .orNot(isAlsoFalse())
+         .orNot(() -> isAlsoFalse())
          .then(() -> doSomething())
          .otherwise(() -> doSomethingElse());
 ----
@@ -154,7 +154,7 @@ if (isFalse()) {
 ----
 Condition.where(isFalse())
          .then(() -> doSomething())
-         .otherwise(isTrue())
+         .otherwise(() -> isTrue())
          .then(() -> doSomethingElse());
 ----
 
@@ -174,7 +174,7 @@ if (isTrue()) {
 ----
 Condition.where(isTrue())
          .then(() -> doSomething())
-         .and(isAlsoTrue())
+         .and(() -> isAlsoTrue())
          .then(() -> doSomethingElse());
 ----
 
@@ -213,7 +213,8 @@ final Optional<String> result = Value.where(isTrue(), () -> TRUE);
 
 [[source,java]]
 ----
-final String result = Value.<String>where(isTrue()).then(() -> TRUE)
+final String result = Value.<String>where(isTrue())
+                           .then(() -> TRUE)
                            .otherwise(() -> FALSE);
 ----
 
@@ -231,7 +232,8 @@ if (!isTrue()) {
 
 [[source,java]]
 ----
-final String result = Value.<String>whereNot(isTrue()).then(() -> TRUE)
+final String result = Value.<String>whereNot(isTrue())
+                           .then(() -> TRUE)
                            .otherwise(() -> FALSE);
 ----
 
@@ -249,7 +251,8 @@ if (isTrue() && alternativeIsTrue()) {
 
 [[source,java]]
 ----
-final String result = Value.<String>where(isTrue()).and(alternativeIsTrue())
+final String result = Value.<String>where(isTrue())
+                           .and(() -> alternativeIsTrue())
                            .then(() -> TRUE)
                            .otherwise(() -> FALSE);
 ----
@@ -268,7 +271,8 @@ if (isTrue() && !alternativeIsFalse()) {
 
 [[source,java]]
 ----
-final String result = Value.<String>where(isTrue()).andNot(alternativeIsFalse())
+final String result = Value.<String>where(isTrue())
+                           .andNot(() -> alternativeIsFalse())
                            .then(() -> TRUE)
                            .otherwise(() -> FALSE);
 ----
@@ -287,7 +291,8 @@ if (isTrue() || alternativeIsTrue()) {
 
 [[source,java]]
 ----
-final String result = Value.<String>where(isTrue()).or(alternativeIsTrue())
+final String result = Value.<String>where(isTrue())
+                           .or(() -> alternativeIsTrue())
                            .then(() -> TRUE)
                            .otherwise(() -> FALSE);
 ----
@@ -306,7 +311,27 @@ if (isTrue() || !isFalse()) {
 
 [[source,java]]
 ----
-final String result = Value.<String>where(isTrue()).orNot(isFalse())
+final String result = Value.<String>where(isTrue())
+                           .orNot(() -> isFalse())
                            .then(() -> TRUE)
                            .otherwise(() -> FALSE);
 ----
+
+### if-then
+
+[[source,java]]
+-----
+Optional<String> result;
+if (isTrue()) {
+    result = Optional.of(TRUE);
+} else {
+    result = Optional.empty();
+}
+-----
+
+[[source,java]]
+-----
+final Optional<String> result = Value.<String>where(isTrue())
+                                     .then(() -> TRUE)
+                                     .optional();
+-----

src/main/java/net/kemitix/conditional/FalseValueClause.java

@@ -21,6 +21,7 @@
 
 package net.kemitix.conditional;
 
+import java.util.Optional;
 import java.util.function.Supplier;
 
 /**
@@ -40,14 +41,13 @@ class FalseValueClause<T> implements Value.ValueClause<T> {
     }
 
     @Override
-    public Value.ValueClause<T> and(final boolean clause) {
+    public Value.ValueClause<T> and(final Supplier<Boolean> clause) {
         return this;
     }
 
     @Override
-    @SuppressWarnings("PMD.ShortMethodName")
+    public Value.ValueClause<T> or(final Supplier<Boolean> clause) {
-    public Value.ValueClause<T> or(final boolean clause) {
+        return Value.where(clause.get());
-        return Value.where(clause);
     }
 
     /**
@@ -62,6 +62,11 @@ class FalseValueClause<T> implements Value.ValueClause<T> {
             return falseSupplier.get();
         }
 
+        @Override
+        public Optional<T> optional() {
+            return Optional.empty();
+        }
+
     }
 
 }

src/main/java/net/kemitix/conditional/TrueValueClause.java

@@ -23,6 +23,7 @@ package net.kemitix.conditional;
 
 import lombok.RequiredArgsConstructor;
 
+import java.util.Optional;
 import java.util.function.Supplier;
 
 /**
@@ -42,13 +43,12 @@ class TrueValueClause<T> implements Value.ValueClause<T> {
     }
 
     @Override
-    public Value.ValueClause<T> and(final boolean clause) {
+    public Value.ValueClause<T> and(final Supplier<Boolean> clause) {
-        return Value.where(clause);
+        return Value.where(clause.get());
     }
 
     @Override
-    @SuppressWarnings("PMD.ShortMethodName")
+    public Value.ValueClause<T> or(final Supplier<Boolean> clause) {
-    public Value.ValueClause<T> or(final boolean clause) {
         return this;
     }
 
@@ -60,7 +60,6 @@ class TrueValueClause<T> implements Value.ValueClause<T> {
     @RequiredArgsConstructor
     private static final class TrueValueSupplier<T> implements ValueSupplier<T> {
 
-        @SuppressWarnings("PMD.BeanMembersShouldSerialize")
         private final Supplier<T> valueSupplier;
 
         @Override
@@ -68,6 +67,11 @@ class TrueValueClause<T> implements Value.ValueClause<T> {
             return valueSupplier.get();
         }
 
+        @Override
+        public Optional<T> optional() {
+            return Optional.ofNullable(valueSupplier.get());
+        }
+
     }
 
 }

src/main/java/net/kemitix/conditional/Value.java

@@ -41,11 +41,10 @@ public interface Value {
      *
      * @return the value from either the trueSupplier or the falseSupplier
      */
-    @SuppressWarnings("PMD.LawOfDemeter")
     static <T> T where(
-            boolean clause,
+            final boolean clause,
-            Supplier<T> trueSupplier,
+            final Supplier<T> trueSupplier,
-            Supplier<T> falseSupplier
+            final Supplier<T> falseSupplier
                       ) {
         return Value.<T>where(clause).then(trueSupplier)
                                      .otherwise(falseSupplier);
@@ -61,8 +60,8 @@ public interface Value {
      * @return an Optional either containing the value from the trueSupplier or empty
      */
     static <T> Optional<T> where(
-            boolean clause,
+            final boolean clause,
-            Supplier<T> trueSupplier
+            final Supplier<T> trueSupplier
                                 ) {
         return Optional.ofNullable(Value.where(clause, trueSupplier, () -> null));
     }
@@ -75,7 +74,6 @@ public interface Value {
      *
      * @return a true or false value clause
      */
-    @SuppressWarnings({"unchecked", "avoidinlineconditionals"})
     static <T> ValueClause<T> where(final boolean clause) {
         return (ValueClause<T>) (clause ? TrueValueClause.TRUE : FalseValueClause.FALSE);
     }
@@ -88,7 +86,7 @@ public interface Value {
      *
      * @return a true or false value clause
      */
-    static <T> ValueClause<T> whereNot(boolean clause) {
+    static <T> ValueClause<T> whereNot(final boolean clause) {
         return where(!clause);
     }
 
@@ -115,7 +113,7 @@ public interface Value {
          *
          * @return a true or false value clause
          */
-        ValueClause<T> and(boolean clause);
+        ValueClause<T> and(Supplier<Boolean> clause);
 
         /**
          * Logically OR combine the current {@link ValueClause} with clause.
@@ -124,8 +122,7 @@ public interface Value {
          *
          * @return a true or false value clause
          */
-        @SuppressWarnings("PMD.ShortMethodName")
+        ValueClause<T> or(Supplier<Boolean> clause);
-        ValueClause<T> or(boolean clause);
 
         /**
          * Logically AND combine the current {@link ValueClause} with boolean opposite of the clause.
@@ -134,8 +131,8 @@ public interface Value {
          *
          * @return a true or false value clause
          */
-        default ValueClause<T> andNot(final boolean clause) {
+        default ValueClause<T> andNot(final Supplier<Boolean> clause) {
-            return and(!clause);
+            return and(() -> !clause.get());
         }
 
         /**
@@ -145,8 +142,8 @@ public interface Value {
          *
          * @return a true or false value clause
          */
-        default ValueClause<T> orNot(boolean clause) {
+        default ValueClause<T> orNot(final Supplier<Boolean> clause) {
-            return or(!clause);
+            return or(() -> !clause.get());
         }
 
         /**
@@ -165,6 +162,12 @@ public interface Value {
              */
             T otherwise(Supplier<T> falseSupplier);
 
+            /**
+             * Returns the value in an Optional if the {@link ValueClause} is true, or an empty Optional if it is false.
+             *
+             * @return an Optional, possibly containing the value
+             */
+            Optional<T> optional();
         }
 
     }

src/test/java/net/kemitix/conditional/ValueTest.java

@@ -4,6 +4,7 @@ import lombok.val;
 import org.junit.Test;
 
 import java.util.Optional;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
@@ -69,7 +70,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueAndTrueIsTrue() {
         //when
-        val result = Value.<String>where(true).and(true)
+        val result = Value.<String>where(true).and(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -79,7 +80,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueAndFalseIsFalse() {
         //when
-        val result = Value.<String>where(true).and(false)
+        val result = Value.<String>where(true).and(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -89,7 +90,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseAndTrueIsFalse() {
         //when
-        val result = Value.<String>where(false).and(true)
+        val result = Value.<String>where(false).and(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -99,7 +100,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseAndFalseIsFalse() {
         //when
-        val result = Value.<String>where(false).and(false)
+        val result = Value.<String>where(false).and(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -109,7 +110,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueOrTrueIsTrue() {
         //when
-        val result = Value.<String>where(true).or(true)
+        val result = Value.<String>where(true).or(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -119,7 +120,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueOrFalseIsTrue() {
         //when
-        val result = Value.<String>where(true).or(false)
+        val result = Value.<String>where(true).or(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -129,7 +130,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseOrTrueIsTrue() {
         //when
-        val result = Value.<String>where(false).or(true)
+        val result = Value.<String>where(false).or(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -139,7 +140,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseOrFalseIsFalse() {
         //when
-        val result = Value.<String>where(false).or(false)
+        val result = Value.<String>where(false).or(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -167,7 +168,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueAndNotTrueIsFalse() {
         //when
-        val result = Value.<String>where(true).andNot(true)
+        val result = Value.<String>where(true).andNot(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -177,7 +178,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueAndNotFalseIsTrue() {
         //when
-        val result = Value.<String>where(true).andNot(false)
+        val result = Value.<String>where(true).andNot(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -187,7 +188,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseAndNotTrueIsFalse() {
         //when
-        val result = Value.<String>where(false).andNot(true)
+        val result = Value.<String>where(false).andNot(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -197,7 +198,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseAndNotFalseIsFalse() {
         //when
-        val result = Value.<String>where(false).andNot(false)
+        val result = Value.<String>where(false).andNot(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -207,7 +208,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueOrNotTrueIsTrue() {
         //when
-        val result = Value.<String>where(true).orNot(true)
+        val result = Value.<String>where(true).orNot(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -217,7 +218,7 @@ public class ValueTest {
     @Test
     public void valueWhereTrueOrNotFalseIsTrue() {
         //when
-        val result = Value.<String>where(true).orNot(false)
+        val result = Value.<String>where(true).orNot(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -227,7 +228,7 @@ public class ValueTest {
     @Test
     public void valueWhereFalseOrNotTrueIsFalse() {
         //when
-        val result = Value.<String>where(false).orNot(true)
+        val result = Value.<String>where(false).orNot(() -> true)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
@@ -237,10 +238,54 @@ public class ValueTest {
     @Test
     public void valueWhereFalseOrNotFalseIsTrue() {
         //when
-        val result = Value.<String>where(false).orNot(false)
+        val result = Value.<String>where(false).orNot(() -> false)
                 .then(() -> TRUE)
                 .otherwise(() -> FALSE);
         //then
         assertThat(result).isEqualTo(TRUE);
     }
+
+    @Test
+    public void valueWhereTrueThenIsNotEmpty() {
+        //given
+        final Optional<Object> result = Value.where(true).then(() -> "value").optional();
+        //then
+        assertThat(result).contains("value");
+    }
+
+    @Test
+    public void valueWhereFalseThenIsEmpty() {
+        //given
+        final Optional<Object> result = Value.where(false).then(() -> "value").optional();
+        //when
+        assertThat(result).isEmpty();
+    }
+
+    @Test
+    public void shortCurcuitOr() {
+        //given
+        final AtomicInteger atomicInteger = new AtomicInteger();
+        //when
+        final Optional<String> result = Value.<String>where(true)
+                .or(() -> atomicInteger.compareAndSet(0, 2))
+                .then(() -> "Pass")
+                .optional();
+        //then
+        assertThat(result).contains("Pass");
+        assertThat(atomicInteger).hasValue(0);
+    }
+
+    @Test
+    public void shortCurcuitAnd() {
+        //given
+        final AtomicInteger atomicInteger = new AtomicInteger();
+        //when
+        final Optional<String> result = Value.<String>where(false)
+                .and(() -> atomicInteger.compareAndSet(0, 2))
+                .then(() -> "Pass")
+                .optional();
+        //then
+        assertThat(result).isEmpty();
+        assertThat(atomicInteger).hasValue(0);
+    }
 }