Merge pull request #2 from F0Xde/master

Allow catching of exceptions in chained runnables

.gitignore

@@ -5,3 +5,5 @@ gradle/
 .gradle/
 logs/
 gradle.properties
+gradlew
+gradlew.bat

src/main/kotlin/net/axay/kspigot/runnables/ChainableRunnables.kt

@@ -4,6 +4,7 @@ package net.axay.kspigot.runnables
 
 import net.axay.kspigot.main.KSpigotMainInstance
 import org.bukkit.Bukkit
+import kotlin.reflect.KClass
 
 abstract class ChainedRunnablePart<T, R>(
     val sync: Boolean
@@ -11,15 +12,43 @@ abstract class ChainedRunnablePart<T, R>(
 
     var next: ChainedRunnablePart<R, *>? = null
 
-    abstract fun execute()
-    
     protected abstract fun invoke(data: T): R
 
+    abstract fun execute()
+
+    abstract fun <E : Exception> executeCatching(
+            @Suppress("UNCHECKED_CAST") exceptionClass: KClass<E> = Exception::class as KClass<E>,
+            exceptionHandler: ((E) -> Unit)? = null,
+    )
+
     protected fun start(data: T) {
-        val realRunnable = Runnable {
+        this.run {
             val result = invoke(data)
             next?.start(result)
         }
+    }
+
+    protected fun <E : Exception> startCatching(
+        data: T,
+        exceptionClass: KClass<E>,
+        exceptionHandler: ((E) -> Unit)?
+    ) {
+        this.run {
+            val result = try {
+                invoke(data)
+            } catch (e: Exception) {
+                if (exceptionClass.isInstance(e)) {
+                    @Suppress("UNCHECKED_CAST")
+                    exceptionHandler?.invoke(e as E)
+                    null
+                } else throw e
+            }
+            if (result != null)
+                next?.startCatching(result, exceptionClass, exceptionHandler)
+        }
+    }
+
+    private fun run(realRunnable: () -> Unit) {
         if (sync)
             Bukkit.getScheduler().runTask(KSpigotMainInstance, realRunnable)
         else
@@ -33,7 +62,11 @@ class ChainedRunnablePartFirst<R>(
     sync: Boolean
 ) : ChainedRunnablePart<Unit, R>(sync) {
 
-    override fun execute() = start(Unit)
+    override fun execute()
+            = start(Unit)
+
+    override fun <E : Exception> executeCatching(exceptionClass: KClass<E>, exceptionHandler: ((E) -> Unit)?)
+            = startCatching(Unit, exceptionClass, exceptionHandler)
 
     override fun invoke(data: Unit) = runnable.invoke()
 
@@ -45,14 +78,19 @@ class ChainedRunnablePartThen<T, R>(
     val previous: ChainedRunnablePart<*, T>
 ) : ChainedRunnablePart<T, R>(sync) {
 
-    override fun execute() = previous.execute()
+    override fun execute()
+            = previous.execute()
+
+    override fun <E : Exception> executeCatching(exceptionClass: KClass<E>, exceptionHandler: ((E) -> Unit)?)
+            = previous.executeCatching(exceptionClass, exceptionHandler)
 
     override fun invoke(data: T) = runnable.invoke(data)
 
 }
 
 // FIRST
-fun <R> firstDo(sync: Boolean, runnable: () -> R) = ChainedRunnablePartFirst(runnable, sync)
+fun <R> firstDo(sync: Boolean, runnable: () -> R)
+        = ChainedRunnablePartFirst(runnable, sync)
 fun <R> firstSync(runnable: () -> R) = firstDo(true, runnable)
 fun <R> firstAsync(runnable: () -> R) = firstDo(false, runnable)