Let on, then and orElse accept varargs, close #4486

Motivation:

So users can directly write:

```java
repeat(5).on(
   chain1,
   chain2
)
```

instead of

```java
repeat(5).on(
  exec(
    chain1,
    chain2
  )
)
```

or

```java
repeat(5).on(
    chain1
      .exec(chain2)
  )
)
```

gatling-core-java/src/main/java/io/gatling/javaapi/core/Choice.java

@@ -22,12 +22,14 @@
 public final class Choice {
   private Choice() {}
 
-  public static WithKey withKey(@NonNull Object key, @NonNull ChainBuilder chain) {
-    return new WithKey(key, chain);
+  public static WithKey withKey(
+      @NonNull Object key, @NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+    return new WithKey(key, chain.exec(chains));
   }
 
-  public static WithWeight withWeight(double weight, @NonNull ChainBuilder chain) {
-    return new WithWeight(weight, chain);
+  public static WithWeight withWeight(
+      double weight, @NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+    return new WithWeight(weight, chain.exec(chains));
   }
 
   /** A choice with an expected key */
@@ -39,7 +41,7 @@ public static final class WithKey {
      * @param key the expected key
      * @param chain the chain that will be triggered if the switch matches the expected key
      */
-    public WithKey(@NonNull Object key, @NonNull ChainBuilder chain) {
+    private WithKey(@NonNull Object key, @NonNull ChainBuilder chain) {
       this.key = key;
       this.chain = chain;
     }

gatling-core-java/src/main/java/io/gatling/javaapi/core/CoreDsl.java

@@ -2479,11 +2479,12 @@ public static RoundRobinSwitch.On<ChainBuilder> roundRobinSwitch() {
    * Errors#exitBlockOnFail(ChainBuilder)}.
    *
    * @param chain the chain to interrupt on error
+   * @param chains other chains
    * @return a new ChainBuilder
    */
   @NonNull
-  public static ChainBuilder exitBlockOnFail(@NonNull ChainBuilder chain) {
-    return ChainBuilder.EMPTY.exitBlockOnFail(chain);
+  public static ChainBuilder exitBlockOnFail(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+    return ChainBuilder.EMPTY.exitBlockOnFail(chain.exec(chains));
   }
 
   /**

gatling-core-java/src/main/java/io/gatling/javaapi/core/condition/DoIf.java

@@ -76,11 +76,12 @@ final class Then<T extends StructureBuilder<T, ?>> {
      * Define the chain to be executed when the condition is true
      *
      * @param chain the chain
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T then(@NonNull ChainBuilder chain) {
-      return wrapped.then_(chain);
+    public T then(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.then_(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/condition/DoIfEquals.java

@@ -129,11 +129,12 @@ final class Then<T extends StructureBuilder<T, ?>> {
      * Define the chain to be executed when the actual and expected values are equal
      *
      * @param chain the "then" chain
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T then(ChainBuilder chain) {
-      return wrapped.then_(chain);
+    public T then(ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.then_(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/condition/DoIfEqualsOrElse.java

@@ -137,11 +137,12 @@ final class Then<T extends StructureBuilder<T, ?>> {
      * Define the chain to be executed when the actual and expected values are equal
      *
      * @param chain the "then "chain
+     * @param chains other chains
      * @return the DSL component for defining the "else" block
      */
     @NonNull
-    public OrElse<T> then(@NonNull ChainBuilder chain) {
-      return new OrElse<>(wrapped.then_(chain));
+    public OrElse<T> then(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return new OrElse<>(wrapped.then_(chain.exec(chains)));
     }
   }
 
@@ -160,12 +161,13 @@ final class OrElse<T extends StructureBuilder<T, ?>> {
     /**
      * Define the chain to be executed when the actual and expected values are not equal
      *
-     * @param orElseChain the "then "chain
+     * @param chain the "then "chain
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T orElse(@NonNull ChainBuilder orElseChain) {
-      return wrapped.orElse(orElseChain);
+    public T orElse(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.orElse(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/condition/DoIfOrElse.java

@@ -76,11 +76,12 @@ final class Then<T extends StructureBuilder<T, ?>> {
      * Define the chain to be executed when the condition is true
      *
      * @param chain the chain
+     * @param chains other chains
      * @return the DSL component for defining the "else" block
      */
     @NonNull
-    public OrElse<T> then(@NonNull ChainBuilder chain) {
-      return new OrElse<>(wrapped.then_(chain));
+    public OrElse<T> then(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return new OrElse<>(wrapped.then_(chain.exec(chains)));
     }
   }
 
@@ -99,12 +100,13 @@ final class OrElse<T extends StructureBuilder<T, ?>> {
     /**
      * Define the chain to be executed when the condition is false
      *
-     * @param orElseChain the "then "chain
+     * @param chain the "then "chain
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T orElse(@NonNull ChainBuilder orElseChain) {
-      return wrapped.orElse(orElseChain);
+    public T orElse(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.orElse(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/condition/DoSwitchOrElse.java

@@ -114,12 +114,13 @@ final class OrElse<T extends StructureBuilder<T, ?>> {
     /**
      * Define the "else" block
      *
-     * @param orElseChain the chain to execute if the actual value doesn't match any of the choices
+     * @param chain the chain to execute if the actual value doesn't match any of the choices
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T orElse(@NonNull ChainBuilder orElseChain) {
-      return wrapped.orElse(orElseChain);
+    public T orElse(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.orElse(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/condition/RandomSwitchOrElse.java

@@ -101,12 +101,13 @@ final class OrElse<T extends StructureBuilder<T, ?>> {
      * Define the chain to be executed when the random number falls into the gap between 100% and
      * the sum of the weights of the choices.
      *
-     * @param orElseChain the "then "chain
+     * @param chain the "then "chain
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T orElse(@NonNull ChainBuilder orElseChain) {
-      return wrapped.orElse(orElseChain);
+    public T orElse(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.orElse(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/error/Errors.java

@@ -45,12 +45,13 @@ public interface Errors<
   /**
    * Define a block that is interrupted for a given virtual user if it experiences a failure.
    *
-   * @param chain the block to be eventually interrupted
+   * @param chain the chain to interrupt on error
+   * @param chains other chains
    * @return a new {@link StructureBuilder}
    */
   @NonNull
-  default T exitBlockOnFail(@NonNull ChainBuilder chain) {
-    return make(wrapped -> wrapped.exitBlockOnFail(chain.wrapped));
+  default T exitBlockOnFail(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+    return make(wrapped -> wrapped.exitBlockOnFail(chain.exec(chains).wrapped));
   }
 
   /**
@@ -147,12 +148,13 @@ final class TryMax<T extends StructureBuilder<T, ?>> {
     /**
      * Define the tried block
      *
-     * @param chain the tried block
+     * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.trying(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.trying(chain.exec(chains));
     }
   }
 

gatling-core-java/src/main/java/io/gatling/javaapi/core/group/Groups.java

@@ -79,11 +79,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the wrapped block
      *
      * @param chain the wrapped block
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.grouping(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.grouping(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/AsLongAs.java

@@ -156,11 +156,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/AsLongAsDuring.java

@@ -512,11 +512,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/DoWhile.java

@@ -108,11 +108,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/DoWhileDuring.java

@@ -516,11 +516,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/During.java

@@ -273,11 +273,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/ForEach.java

@@ -135,11 +135,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/Forever.java

@@ -75,11 +75,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }

gatling-core-java/src/main/java/io/gatling/javaapi/core/loop/Repeat.java

@@ -128,11 +128,12 @@ final class On<T extends StructureBuilder<T, ?>> {
      * Define the loop content
      *
      * @param chain the loop content
+     * @param chains other chains
      * @return a new {@link StructureBuilder}
      */
     @NonNull
-    public T on(@NonNull ChainBuilder chain) {
-      return wrapped.loop(chain);
+    public T on(@NonNull ChainBuilder chain, @NonNull ChainBuilder... chains) {
+      return wrapped.loop(chain.exec(chains));
     }
   }
 }