Merge pull request #149 from jglick/StepExecutions

Improved `StepExecutions`, available outside test scope

src/main/java/org/jenkinsci/plugins/workflow/steps/StepExecutions.java

@@ -0,0 +1,134 @@
+/*
+ * The MIT License
+ *
+ * Copyright 2019 CloudBees, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+package org.jenkinsci.plugins.workflow.steps;
+
+/**
+ * Builder for simple {@link StepExecution} implementations.
+ * Convenient for use from {@link Step#start} when a permanent serial form is unimportant.
+ * Use {@link StepContext#get} to access contextual objects as usual.
+ * <p>The lambda arguments may refer to {@link Step} parameter fields directly.
+ */
+public class StepExecutions {
+
+    @FunctionalInterface
+    public interface SynchronousBody {
+        Object call(StepContext context) throws Exception;
+    }
+
+    @FunctionalInterface
+    public interface SynchronousBodyVoid {
+        void call(StepContext context) throws Exception;
+        default SynchronousBody asReturn() {
+            return c -> {
+                call(c);
+                return null;
+            };
+        }
+    }
+
+    /**
+     * Creates a {@link SynchronousStepExecution} running a given block with a return value.
+     */
+    public static StepExecution synchronous(StepContext context, SynchronousBody body) {
+        return new SynchronousImpl(context, body);
+    }
+
+    /**
+     * Creates a {@link SynchronousStepExecution} running a given block.
+     */
+    public static StepExecution synchronousVoid(StepContext context, SynchronousBodyVoid body) {
+        return new SynchronousImpl(context, body.asReturn());
+    }
+
+    private static class SynchronousImpl extends SynchronousStepExecution<Object> {
+        private static final long serialVersionUID = 1;
+        private transient final SynchronousBody body;
+        SynchronousImpl(StepContext context, SynchronousBody body) {
+            super(context);
+            this.body = body;
+        }
+        @Override protected Object run() throws Exception {
+            return body.call(getContext());
+        }
+    }
+
+    /**
+     * Creates a {@link SynchronousNonBlockingStepExecution} running a given block with a return value.
+     */
+    public static StepExecution synchronousNonBlocking(StepContext context, SynchronousBody body) {
+        return new SynchronousNonBlockingImpl(context, body);
+    }
+
+    /**
+     * Creates a {@link SynchronousNonBlockingStepExecution} running a given block.
+     */
+    public static StepExecution synchronousNonBlockingVoid(StepContext context, SynchronousBodyVoid body) {
+        return new SynchronousNonBlockingImpl(context, body.asReturn());
+    }
+
+    private static class SynchronousNonBlockingImpl extends SynchronousNonBlockingStepExecution<Object> {
+        private static final long serialVersionUID = 1;
+        private transient final SynchronousBody body;
+        SynchronousNonBlockingImpl(StepContext context, SynchronousBody body) {
+            super(context);
+            this.body = body;
+        }
+        @Override protected Object run() throws Exception {
+            return body.call(getContext());
+        }
+    }
+
+    @FunctionalInterface
+    public interface BlockBody {
+        void call(StepContext context, BodyInvoker invoker) throws Exception;
+    }
+
+    /**
+     * Creates a block-scoped execution allowing various initial actions including {@link BodyInvoker#withContext}.
+     * There is no pluggable final action, since {@link BodyExecutionCallback#wrap} is used, so it is a simple tail call.
+     */
+    public static StepExecution block(StepContext context, BlockBody body) {
+        return new BlockImpl(context, body);
+    }
+
+    private static class BlockImpl extends StepExecution {
+        private static final long serialVersionUID = 1;
+        private transient final BlockBody body;
+        BlockImpl(StepContext context, BlockBody body) {
+            super(context);
+            this.body = body;
+        }
+        @Override public boolean start() throws Exception {
+            StepContext context = getContext();
+            BodyInvoker invoker = context.newBodyInvoker();
+            body.call(context, invoker);
+            invoker.withCallback(BodyExecutionCallback.wrap(context)).start();
+            return false;
+        }
+    }
+
+    private StepExecutions() {}
+
+}