Code polish for the shell executors

src/dorkbox/util/process/ShellAsyncExecutor.java

@@ -1,10 +1,22 @@
+/*
+ * Copyright 2017 dorkbox, llc
+ *
+ * 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 dorkbox.util.process;
 
-/**
- *
- */
 public
-class ShellAsyncExecutor {
+class ShellAsyncExecutor extends ShellExecutor {
     /**
      * This is a convenience method to easily create a default process. Will immediately return, and does not wait for the process to finish
      *
@@ -13,12 +25,21 @@ class ShellAsyncExecutor {
      *
      * @return true if the process ran successfully (exit value was 0), otherwise false
      */
-    public static void run(String executableName, String... args) {
+    public static
+    boolean run(String executableName, String... args) {
         ShellExecutor shell = new ShellExecutor();
         shell.setExecutable(executableName);
         shell.addArguments(args);
         shell.createReadWriterThreads();
 
-        shell.start(false);
+        return shell.start(false) == 0;
+    }
+
+    @Override
+    public
+    int start() {
+        // always have to make sure separate threads are started, otherwise the calling process can hang.
+        createReadWriterThreads();
+        return super.start(false);
     }
 }

src/dorkbox/util/process/ShellExecutor.java

@@ -71,7 +71,7 @@ class ShellExecutor {
     private List<String> fullCommand;
 
     /**
-     * This is a convenience method to easily create a default ShellExecutor. Will block until the process is finished running
+     * This is a convenience method to easily create a default process. Will block until the process is finished running
      *
      * @param executableName the name of the executable to run
      * @param args the arguments for the executable