1 /*
   2  * Copyright (c) 2019, 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 com.sun.tools.javac.code;
  27 
  28 import com.sun.source.util.ParameterNameProvider;
  29 import com.sun.tools.javac.code.Symbol.ParamSymbol;
  30 import com.sun.tools.javac.util.Context;
  31 import com.sun.tools.javac.util.Name;
  32 import com.sun.tools.javac.util.Names;
  33 
  34 /**
  35  * A Context class, that can return additional useful information for Symbols, currently
  36  * parameter names. It does so by calling user-supplied {@link ParameterNameProvider}.
  37  *
  38  * <p><b>This is NOT part of any supported API.
  39  * If you write code that depends on this, you do so at your own risk.
  40  * This code and its internal interfaces are subject to change or
  41  * deletion without notice.</b>
  42  */
  43 public class MissingInfoHandler {
  44     protected static final Context.Key<MissingInfoHandler> missingInfoHandlerWrapperKey = new Context.Key<>();
  45 
  46     public static MissingInfoHandler instance(Context context) {
  47         MissingInfoHandler instance = context.get(missingInfoHandlerWrapperKey);
  48         if (instance == null)
  49             instance = new MissingInfoHandler(context);
  50         return instance;
  51     }
  52 
  53     private final Names names;
  54     private ParameterNameProvider parameterNameProvider;
  55 
  56     protected MissingInfoHandler(Context context) {
  57         context.put(missingInfoHandlerWrapperKey, this);
  58         names = Names.instance(context);
  59     }
  60 
  61     public Name getParameterName(ParamSymbol parameter) {
  62         if (parameterNameProvider != null) {
  63             CharSequence name = parameterNameProvider.getParameterName(parameter);
  64             if (name != null) {
  65                 return names.fromString(name.toString());
  66             }
  67         }
  68 
  69         return null;
  70     }
  71 
  72     public void setDelegate(ParameterNameProvider delegate) {
  73         this.parameterNameProvider = delegate;
  74     }
  75 }