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
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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 =
47         new Context.Key<DeferredLintHandler>();
48 
instance(Context context)49     public static DeferredLintHandler instance(Context context) {
50         DeferredLintHandler instance = context.get(deferredLintHandlerKey);
51         if (instance == null)
52             instance = new DeferredLintHandler(context);
53         return instance;
54     }
55 
DeferredLintHandler(Context context)56     protected DeferredLintHandler(Context context) {
57         context.put(deferredLintHandlerKey, this);
58         this.currentPos = IMMEDIATE_POSITION;
59     }
60 
61     /**An interface for deferred lint reporting - loggers passed to
62      * {@link #report(LintLogger) } will be called when
63      * {@link #flush(DiagnosticPosition) } is invoked.
64      */
65     public interface LintLogger {
report()66         void report();
67     }
68 
69     private DiagnosticPosition currentPos;
70     private Map<DiagnosticPosition, ListBuffer<LintLogger>> loggersQueue = new HashMap<DiagnosticPosition, ListBuffer<LintLogger>>();
71 
72     /**Associate the given logger with the current position as set by {@link #setPos(DiagnosticPosition) }.
73      * Will be invoked when {@link #flush(DiagnosticPosition) } will be invoked with the same position.
74      * <br>
75      * Will invoke the logger synchronously if {@link #immediate() } was called
76      * instead of {@link #setPos(DiagnosticPosition) }.
77      */
report(LintLogger logger)78     public void report(LintLogger logger) {
79         if (currentPos == IMMEDIATE_POSITION) {
80             logger.report();
81         } else {
82             ListBuffer<LintLogger> loggers = loggersQueue.get(currentPos);
83             if (loggers == null) {
84                 loggersQueue.put(currentPos, loggers = new ListBuffer<>());
85             }
86             loggers.append(logger);
87         }
88     }
89 
90     /**Invoke all {@link LintLogger}s that were associated with the provided {@code pos}.
91      */
flush(DiagnosticPosition pos)92     public void flush(DiagnosticPosition pos) {
93         ListBuffer<LintLogger> loggers = loggersQueue.get(pos);
94         if (loggers != null) {
95             for (LintLogger lintLogger : loggers) {
96                 lintLogger.report();
97             }
98             loggersQueue.remove(pos);
99         }
100     }
101 
102     /**Sets the current position to the provided {@code currentPos}. {@link LintLogger}s
103      * passed to subsequent invocations of {@link #report(LintLogger) } will be associated
104      * with the given position.
105      */
setPos(DiagnosticPosition currentPos)106     public DiagnosticPosition setPos(DiagnosticPosition currentPos) {
107         DiagnosticPosition prevPosition = this.currentPos;
108         this.currentPos = currentPos;
109         return prevPosition;
110     }
111 
112     /**{@link LintLogger}s passed to subsequent invocations of
113      * {@link #report(LintLogger) } will be invoked immediately.
114      */
immediate()115     public DiagnosticPosition immediate() {
116         return setPos(IMMEDIATE_POSITION);
117     }
118 
119     private static final DiagnosticPosition IMMEDIATE_POSITION = new DiagnosticPosition() {
120         @Override
121         public JCTree getTree() {
122             Assert.error();
123             return null;
124         }
125 
126         @Override
127         public int getStartPosition() {
128             Assert.error();
129             return -1;
130         }
131 
132         @Override
133         public int getPreferredPosition() {
134             Assert.error();
135             return -1;
136         }
137 
138         @Override
139         public int getEndPosition(EndPosTable endPosTable) {
140             Assert.error();
141             return -1;
142         }
143     };
144 }
145