Throw checked exceptions from side effects (#132)

sdk-java-blocking/src/main/java/dev/restate/sdk/blocking/RestateContext.java

@@ -7,7 +7,6 @@
 import io.grpc.MethodDescriptor;
 import java.time.Duration;
 import java.util.Optional;
-import java.util.function.Supplier;
 import javax.annotation.Nonnull;
 import javax.annotation.concurrent.NotThreadSafe;
 
@@ -104,8 +103,8 @@ <T extends MessageLite> void oneWayCall(
   <T extends MessageLite> void delayedCall(
       MethodDescriptor<T, ? extends MessageLite> methodDescriptor, T parameter, Duration delay);
 
-  /** Shorthand for {@link #sideEffect(TypeTag, Supplier)}. */
-  default <T> T sideEffect(Class<T> clazz, Supplier<T> action) {
+  /** Shorthand for {@link #sideEffect(TypeTag, ThrowingSupplier)}. */
+  default <T> T sideEffect(Class<T> clazz, ThrowingSupplier<T> action) {
     return sideEffect(TypeTag.ofClass(clazz), action);
   }
 
@@ -120,10 +119,10 @@ default <T> T sideEffect(Class<T> clazz, Supplier<T> action) {
    * @param <T> type of the return value.
    * @return value of the side effect operation.
    */
-  <T> T sideEffect(TypeTag<T> typeTag, Supplier<T> action);
+  <T> T sideEffect(TypeTag<T> typeTag, ThrowingSupplier<T> action);
 
-  /** Like {@link #sideEffect(TypeTag, Supplier)}, but without returning a value. */
-  default void sideEffect(Runnable runnable) {
+  /** Like {@link #sideEffect(TypeTag, ThrowingSupplier)}, but without returning a value. */
+  default void sideEffect(ThrowingRunnable runnable) {
     sideEffect(
         TypeTag.VOID,
         () -> {

sdk-java-blocking/src/main/java/dev/restate/sdk/blocking/RestateContextImpl.java

@@ -10,7 +10,6 @@
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
-import java.util.function.Supplier;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
 
@@ -72,7 +71,7 @@ public <T extends MessageLite> void delayedCall(
   }
 
   @Override
-  public <T> T sideEffect(TypeTag<T> typeTag, Supplier<T> action) {
+  public <T> T sideEffect(TypeTag<T> typeTag, ThrowingSupplier<T> action) {
     CompletableFuture<CompletableFuture<T>> enterFut = new CompletableFuture<>();
     syscalls.enterSideEffectBlock(
         typeTag,

sdk-java-blocking/src/main/java/dev/restate/sdk/blocking/ThrowingRunnable.java

@@ -0,0 +1,9 @@
+package dev.restate.sdk.blocking;
+
+/** Like {@link Runnable} but can throw checked exceptions. */
+@FunctionalInterface
+public interface ThrowingRunnable {
+
+  /** Run, potentially throwing an exception. */
+  void run() throws Throwable;
+}

sdk-java-blocking/src/main/java/dev/restate/sdk/blocking/ThrowingSupplier.java

@@ -0,0 +1,15 @@
+package dev.restate.sdk.blocking;
+
+import java.util.function.Supplier;
+
+/** Like {@link Supplier} but can throw checked exceptions. */
+@FunctionalInterface
+public interface ThrowingSupplier<T> {
+
+  /**
+   * Get a result, potentially throwing an exception.
+   *
+   * @return a result
+   */
+  T get() throws Throwable;
+}