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1 /**
2  * Copyright (c) 2004-2011 QOS.ch
3  * All rights reserved.
4  *
5  * Permission is hereby granted, free  of charge, to any person obtaining
6  * a  copy  of this  software  and  associated  documentation files  (the
7  * "Software"), to  deal in  the Software without  restriction, including
8  * without limitation  the rights to  use, copy, modify,  merge, publish,
9  * distribute,  sublicense, and/or sell  copies of  the Software,  and to
10  * permit persons to whom the Software  is furnished to do so, subject to
11  * the following conditions:
12  *
13  * The  above  copyright  notice  and  this permission  notice  shall  be
14  * included in all copies or substantial portions of the Software.
15  *
16  * THE  SOFTWARE IS  PROVIDED  "AS  IS", WITHOUT  WARRANTY  OF ANY  KIND,
17  * EXPRESS OR  IMPLIED, INCLUDING  BUT NOT LIMITED  TO THE  WARRANTIES OF
18  * MERCHANTABILITY,    FITNESS    FOR    A   PARTICULAR    PURPOSE    AND
19  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
20  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
21  * OF CONTRACT, TORT OR OTHERWISE,  ARISING FROM, OUT OF OR IN CONNECTION
22  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23  *
24  */
25 package org.slf4j.agent;
26 
27 import java.io.ByteArrayInputStream;
28 import java.io.IOException;
29 import java.lang.instrument.Instrumentation;
30 import java.util.Date;
31 import java.util.Properties;
32 
33 import org.slf4j.instrumentation.LogTransformer;
34 
35 /**
36  * Entry point for slf4j-ext when used as a Java agent.
37  *
38  */
39 public class AgentPremain {
40 
41     /**
42      * JavaAgent premain entry point as specified in the MANIFEST.MF file. See
43      * {@link http
44      * ://java.sun.com/javase/6/docs/api/java/lang/instrument/package-
45      * summary.html} for details.
46      *
47      * @param agentArgument
48      *            string provided after "=" up to first space
49      * @param instrumentation
50      *            instrumentation environment provided by the JVM
51      */
premain(String agentArgument, Instrumentation instrumentation)52     public static void premain(String agentArgument, Instrumentation instrumentation) {
53 
54         // We cannot do sanity checks for slf4j here as the jars loaded
55         // by the application are not visible here.
56 
57         LogTransformer.Builder builder = new LogTransformer.Builder();
58         builder = builder.addEntryExit(true);
59 
60         if (agentArgument != null) {
61             Properties args = parseArguments(agentArgument, ",");
62 
63             if (args.containsKey(AgentOptions.VERBOSE)) {
64                 builder = builder.verbose(true);
65             }
66 
67             if (args.containsKey(AgentOptions.TIME)) {
68                 printStartStopTimes();
69             }
70 
71             if (args.containsKey(AgentOptions.IGNORE)) {
72                 String ignore = args.getProperty(AgentOptions.IGNORE);
73                 builder = builder.ignore(ignore.split(":"));
74             }
75 
76             if (args.containsKey(AgentOptions.LEVEL)) {
77                 builder = builder.level(args.getProperty(AgentOptions.LEVEL));
78             }
79         }
80 
81         instrumentation.addTransformer(builder.build());
82     }
83 
84     /**
85      * Consider the argument string to be a property file (by converting the
86      * splitter character to line feeds), and then reading it like any other
87      * property file.
88      *
89      *
90      * @param agentArgument
91      *            string given by instrumentation framework
92      * @param separator
93      *            String to convert to line feeds
94      * @return argument converted to properties
95      */
parseArguments(String agentArgument, String separator)96     private static Properties parseArguments(String agentArgument, String separator) {
97         Properties p = new Properties();
98         try {
99             String argumentAsLines = agentArgument.replaceAll(separator, "\n");
100             p.load(new ByteArrayInputStream(argumentAsLines.getBytes()));
101         } catch (IOException e) {
102             String s = "Could not load arguments as properties";
103             throw new RuntimeException(s, e);
104         }
105         return p;
106     }
107 
108     /**
109      * Print the start message to System.err with the time NOW, and register a
110      * shutdown hook which will print the stop message to System.err with the
111      * time then and the number of milliseconds passed since.
112      *
113      */
printStartStopTimes()114     private static void printStartStopTimes() {
115         final long start = System.currentTimeMillis();
116 
117         System.err.println("Start at " + new Date());
118 
119         Thread hook = new Thread() {
120             @Override
121             public void run() {
122                 long timePassed = System.currentTimeMillis() - start;
123                 System.err.println("Stop at " + new Date() + ", execution time = " + timePassed + " ms");
124             }
125         };
126         Runtime.getRuntime().addShutdownHook(hook);
127     }
128 }