[Feature] AbstractCommandExecutor.commandType difficult to understand (#1833)

issue: https://github.com/apache/incubator-dolphinscheduler/issues/1831

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/AbstractCommandExecutor.java

@@ -207,7 +207,7 @@ public abstract class AbstractCommandExecutor {
         // merge error information to standard output stream
         processBuilder.redirectErrorStream(true);
         // setting up user to run commands
-        processBuilder.command("sudo", "-u", tenantCode, commandType(), commandFile);
+        processBuilder.command("sudo", "-u", tenantCode, commandInterpreter(), commandFile);
 
         process = processBuilder.start();
 
@@ -561,7 +561,7 @@ public abstract class AbstractCommandExecutor {
 
 
     protected abstract String buildCommandFilePath();
-    protected abstract String commandType();
+    protected abstract String commandInterpreter();
     protected abstract boolean checkFindApp(String line);
     protected abstract void createCommandFileIfNotExists(String execCommand, String commandFile) throws IOException;
 }

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/PythonCommandExecutor.java

@@ -113,7 +113,7 @@ public class PythonCommandExecutor extends AbstractCommandExecutor {
      * @return python home
      */
     @Override
-    protected String commandType() {
+    protected String commandInterpreter() {
         String pythonHome = getPythonHome(envFile);
         if (StringUtils.isEmpty(pythonHome)){
             return PYTHON;

dolphinscheduler-server/src/main/java/org/apache/dolphinscheduler/server/worker/task/ShellCommandExecutor.java

@@ -74,7 +74,7 @@ public class ShellCommandExecutor extends AbstractCommandExecutor {
      * @return command type
      */
     @Override
-    protected String commandType() {
+    protected String commandInterpreter() {
         return SH;
     }