Merge pull request #51 from palantir/feature/enable-extra-way-of-gene…

…rating-success-or-failure

Generate success or failure from lambda

src/main/java/com/palantir/docker/compose/connection/waiting/Attempt.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2016 Palantir Technologies, Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.palantir.docker.compose.connection.waiting;
+
+@FunctionalInterface
+public interface Attempt {
+    boolean attempt() throws Exception;
+}

src/main/java/com/palantir/docker/compose/connection/waiting/SuccessOrFailure.java

@@ -22,6 +22,14 @@
 
 @Value.Immutable
 public abstract class SuccessOrFailure {
+    public static SuccessOrFailure onResultOf(Attempt attempt) {
+        try {
+            return fromBoolean(attempt.attempt(), "Attempt to complete healthcheck failed");
+        } catch(Exception e) {
+            return fromException(e);
+        }
+    }
+
     @Value.Parameter protected abstract Optional<String> optionalFailureMessage();
 
     public static SuccessOrFailure success() {

src/test/java/com/palantir/docker/compose/connection/waiting/SuccessOrFailureShould.java

@@ -50,4 +50,30 @@ public void fail_from_an_exception() {
                 containsString("oh no")
             ))));
     }
+
+    @Test
+    public void succeed_on_a_lambda_that_returns_true() {
+        SuccessOrFailure successFromLambda = SuccessOrFailure.onResultOf(() -> true);
+        assertThat(successFromLambda, is(successful()));
+    }
+
+    @Test
+    public void fail_on_a_lambda_that_throws_an_exception() {
+        SuccessOrFailure failureFromLambda = SuccessOrFailure.onResultOf(() -> {
+            throw new IllegalArgumentException("oh no");
+        });
+
+        assertThat(failureFromLambda,
+                is(failureWithMessage(both(
+                        containsString("IllegalArgumentException")).and(
+                        containsString("oh no")
+                ))));
+    }
+
+    @Test
+    public void fail_on_a_lambda_that_returns_false() {
+        SuccessOrFailure failureFromLambda = SuccessOrFailure.onResultOf(() -> false);
+
+        assertThat(failureFromLambda, is(failureWithMessage("Attempt to complete healthcheck failed")));
+    }
 }