[ONOS-7732] Automating switch workflow: api, app, and sample workflows

Change-Id: Iee87d4fe6cf61c1f8904d1d77df5f913a712b64a
diff --git a/apps/workflow/api/src/main/java/org/onosproject/workflow/api/EventTimeoutTask.java b/apps/workflow/api/src/main/java/org/onosproject/workflow/api/EventTimeoutTask.java
new file mode 100644
index 0000000..92516d4
--- /dev/null
+++ b/apps/workflow/api/src/main/java/org/onosproject/workflow/api/EventTimeoutTask.java
@@ -0,0 +1,152 @@
+/*
+ * Copyright 2018-present Open Networking Foundation
+ *
+ * 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 org.onosproject.workflow.api;
+
+import com.google.common.base.MoreObjects;
+
+import java.util.Objects;
+
+/**
+ * Class for event timeout task.
+ */
+public final class EventTimeoutTask extends HandlerTask {
+
+    /**
+     * Event type (Class name of event).
+     */
+    private final String eventType;
+
+    /**
+     * Event hint value for finding target event.
+     */
+    private final String eventHint;
+
+    /**
+     * Constructor of EventTimeoutTask.
+     * @param builder builder of EventTimeoutTask
+     */
+    private EventTimeoutTask(Builder builder) {
+        super(builder);
+        this.eventType = builder.eventType;
+        this.eventHint = builder.eventHint;
+    }
+
+    /**
+     * Gets event type (Class name of event).
+     * @return event type
+     */
+    public String eventType() {
+        return eventType;
+    }
+
+    /**
+     * Gets event hint value for finding target event.
+     * @return event hint string
+     */
+    public String eventHint() {
+        return eventHint;
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.toString());
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        }
+        if (!(obj instanceof EventTask)) {
+            return false;
+        }
+        return Objects.equals(this.eventType(), ((EventTask) obj).eventType())
+                && Objects.equals(this.eventHint(), ((EventTask) obj).eventHint());
+    }
+
+    @Override
+    public String toString() {
+        return MoreObjects.toStringHelper(getClass())
+                .add("context", context())
+                .add("workletType", workletType())
+                .add("eventType", eventType())
+                .add("eventHint", eventHint())
+                .toString();
+    }
+
+    /**
+     * Gets a instance of builder.
+     * @return instance of builder
+     */
+    public static Builder builder() {
+        return new Builder();
+    }
+
+    /**
+     * Builder of EventTimeoutTask.
+     */
+    public static class Builder extends HandlerTask.Builder {
+        /**
+         * Event type (Class name of event).
+         */
+        private String eventType;
+
+        /**
+         * Event hint value for finding target event.
+         */
+        private String eventHint;
+
+        /**
+         * Sets Event type (Class name of event).
+         * @param eventType event type
+         * @return builder of EventTimeoutTask
+         */
+        public Builder eventType(String eventType) {
+            this.eventType = eventType;
+            return this;
+        }
+
+        /**
+         * Sets event hint string for finding target event.
+         * @param eventHint event hint string
+         * @return builder of EventTimeoutTask
+         */
+        public Builder eventHint(String eventHint) {
+            this.eventHint = eventHint;
+            return this;
+        }
+
+        @Override
+        public Builder context(WorkflowContext context) {
+            super.context(context);
+            return this;
+        }
+
+        @Override
+        public Builder workletType(String workletType) {
+            super.workletType(workletType);
+            return this;
+        }
+
+        /**
+         * Builds EventTimeoutTask.
+         * @return instance of EventTimeoutTask
+         */
+        public EventTimeoutTask build() {
+            return new EventTimeoutTask(this);
+        }
+    }
+}