1 /*
   2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package jdk.packager.services;
  27 
  28 import jdk.packager.services.userjvmoptions.PreferencesUserJvmOptions;
  29 import java.util.Iterator;
  30 import java.util.Map;
  31 import java.util.ServiceLoader;
  32 
  33 /**
  34  * Runtime access to the UserJVMOptions.
  35  *
  36  * This class is not typically available in the Java Runtime, you must
  37  * explicitly include the 'jdk.packager.services' module from the jmod directory
  38  * of the JDK as part of your application bundle.
  39  *
  40  * @since 9
  41  */
  42 public interface UserJvmOptionsService {
  43 
  44     /**
  45      * Get the instance of UserJvmOptionService to use.  Which one to use is
  46      * configured by the packager and the launcher.  Do not directly
  47      * instantiate any instance of this interface, use this method to get
  48      * an appropriate instance.
  49      *
  50      * @return the instance of UserJvmOptionsService for your application.
  51      */
  52     static UserJvmOptionsService getUserJVMDefaults() {
  53         ServiceLoader<UserJvmOptionsService> loader = ServiceLoader.load(UserJvmOptionsService.class);
  54         Iterator<UserJvmOptionsService> iter = loader.iterator();
  55         if (iter.hasNext()) {
  56             return iter.next();
  57         } else {
  58             return new PreferencesUserJvmOptions();
  59         }
  60     }
  61 
  62     /**
  63      * The "current" set of UserJVMOptions.
  64      *
  65      * This will take effect on the next application start, and this may not
  66      * reflect the current set of UserJVMOptions used to start this application.
  67      *
  68      * @return A map of the keys and values.  Alterations to this map will not
  69      *         change the stored UserJVMOptions
  70      */
  71     Map<String, String> getUserJVMOptions();
  72 
  73     /**
  74      * Sets the passed in options as the UserJVMOptions.
  75      *
  76      * If the application has specified default values and those keys are not
  77      * in this map, they will be replaced by the default values.
  78      *
  79      * No validation or error checking is performed on these values.  It is
  80      * entirely possible that you may provide a set of UserJVMOptions that
  81      * may prevent the normal startup of your application and may require
  82      * manual intervention to resolve.
  83      *
  84      * @param options The UserJVMOptions to set.
  85      */
  86     void setUserJVMOptions(Map<String, String> options);
  87 
  88     /**
  89      * The "default" set of UserJVMOptions.
  90      *
  91      * This returns the default set of keys and values that the application has
  92      * been configured to use.
  93      *
  94      * @return the keys and values of the default UserJVMOptions.
  95      * @throws UnsupportedOperationException if the defaults cannot be calculated.
  96      */
  97     Map<String, String> getUserJVMOptionDefaults();
  98 }