1 /*
2  * Copyright (c) 2011, 2013, 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 java.util.HashMap;
29 import java.util.Map;
30 
31 import com.sun.tools.javac.tree.EndPosTable;
32 import com.sun.tools.javac.tree.JCTree;
33 import com.sun.tools.javac.util.Assert;
34 import com.sun.tools.javac.util.Context;
35 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
36 import com.sun.tools.javac.util.ListBuffer;
37 
38 /**
39  *
40  * <p><b>This is NOT part of any supported API.
41  * If you write code that depends on this, you do so at your own risk.
42  * This code and its internal interfaces are subject to change or
43  * deletion without notice.</b>
44  */
45 public class DeferredLintHandler {
46     protected static final Context.Key<DeferredLintHandler> deferredLintHandlerKey = new Context.Key<>();
47 
instance(Context context)48     public static DeferredLintHandler instance(Context context) {
49         DeferredLintHandler instance = context.get(deferredLintHandlerKey);
50         if (instance == null)
51             instance = new DeferredLintHandler(context);
52         return instance;
53     }
54 
DeferredLintHandler(Context context)55     protected DeferredLintHandler(Context context) {
56         context.put(deferredLintHandlerKey, this);
57         this.currentPos = IMMEDIATE_POSITION;
58     }
59 
60     /**An interface for deferred lint reporting - loggers passed to
61      * {@link #report(LintLogger) } will be called when
62      * {@link #flush(DiagnosticPosition) } is invoked.
63      */
64     public interface LintLogger {
report()65         void report();
66     }
67 
68     private DiagnosticPosition currentPos;
69     private Map<DiagnosticPosition, ListBuffer<LintLogger>> loggersQueue = new HashMap<>();
70 
71     /**Associate the given logger with the current position as set by {@link #setPos(DiagnosticPosition) }.
72      * Will be invoked when {@link #flush(DiagnosticPosition) } will be invoked with the same position.
73      * <br>
74      * Will invoke the logger synchronously if {@link #immediate() } was called
75      * instead of {@link #setPos(DiagnosticPosition) }.
76      */
report(LintLogger logger)77     public void report(LintLogger logger) {
78         if (currentPos == IMMEDIATE_POSITION) {
79             logger.report();
80         } else {
81             ListBuffer<LintLogger> loggers = loggersQueue.get(currentPos);
82             if (loggers == null) {
83                 loggersQueue.put(currentPos, loggers = new ListBuffer<>());
84             }
85             loggers.append(logger);
86         }
87     }
88 
89     /**Invoke all {@link LintLogger}s that were associated with the provided {@code pos}.
90      */
flush(DiagnosticPosition pos)91     public void flush(DiagnosticPosition pos) {
92         ListBuffer<LintLogger> loggers = loggersQueue.get(pos);
93         if (loggers != null) {
94             for (LintLogger lintLogger : loggers) {
95                 lintLogger.report();
96             }
97             loggersQueue.remove(pos);
98         }
99     }
100 
101     /**Sets the current position to the provided {@code currentPos}. {@link LintLogger}s
102      * passed to subsequent invocations of {@link #report(LintLogger) } will be associated
103      * with the given position.
104      */
setPos(DiagnosticPosition currentPos)105     public DiagnosticPosition setPos(DiagnosticPosition currentPos) {
106         DiagnosticPosition prevPosition = this.currentPos;
107         this.currentPos = currentPos;
108         return prevPosition;
109     }
110 
111     /**{@link LintLogger}s passed to subsequent invocations of
112      * {@link #report(LintLogger) } will be invoked immediately.
113      */
immediate()114     public DiagnosticPosition immediate() {
115         return setPos(IMMEDIATE_POSITION);
116     }
117 
118     private static final DiagnosticPosition IMMEDIATE_POSITION = new DiagnosticPosition() {
119         @Override
120         public JCTree getTree() {
121             Assert.error();
122             return null;
123         }
124 
125         @Override
126         public int getStartPosition() {
127             Assert.error();
128             return -1;
129         }
130 
131         @Override
132         public int getPreferredPosition() {
133             Assert.error();
134             return -1;
135         }
136 
137         @Override
138         public int getEndPosition(EndPosTable endPosTable) {
139             Assert.error();
140             return -1;
141         }
142     };
143 }
144