1/*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements.  See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License.  You may obtain a copy of the License at
8 *
9 *     http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17
18package java.util.logging;
19
20import java.text.MessageFormat;
21import java.util.Date;
22import java.util.ResourceBundle;
23
24/**
25 * Formatter to convert a {@link LogRecord} into an XML string. The DTD
26 * specified in Appendix A to the Java Logging APIs specification is used.
27 * {@code XMLFormatter} uses the output handler's encoding if it is specified,
28 * otherwise the default platform encoding is used instead. UTF-8 is the
29 * recommended encoding.
30 */
31public class XMLFormatter extends Formatter {
32
33    private static final String indent = "    ";
34
35    /**
36     * Constructs a new {@code XMLFormatter}.
37     */
38    public XMLFormatter() {
39    }
40
41    /**
42     * Converts a {@code LogRecord} into an XML string.
43     *
44     * @param r
45     *            the log record to be formatted.
46     * @return the log record formatted as an XML string.
47     */
48    @Override
49    public String format(LogRecord r) {
50        // call a method of LogRecord to ensure not null
51        long time = r.getMillis();
52        // format to date
53        String date = MessageFormat.format("{0, date} {0, time}", new Object[] { new Date(time) });
54        String nl = System.lineSeparator();
55
56        StringBuilder sb = new StringBuilder();
57        sb.append("<record>").append(nl);
58        append(sb, 1, "date", date);
59        append(sb, 1, "millis", time);
60        append(sb, 1, "sequence", r.getSequenceNumber());
61        if (r.getLoggerName() != null) {
62            append(sb, 1, "logger", r.getLoggerName());
63        }
64        append(sb, 1, "level", r.getLevel().getName());
65        if (r.getSourceClassName() != null) {
66            append(sb, 1, "class", r.getSourceClassName());
67        }
68        if (r.getSourceMethodName() != null) {
69            append(sb, 1, "method", r.getSourceMethodName());
70        }
71        append(sb, 1, "thread", r.getThreadID());
72        formatMessages(r, sb);
73        Object[] params = r.getParameters();
74        if (params != null) {
75            for (Object element : params) {
76                append(sb, 1, "param", element);
77            }
78        }
79        formatThrowable(r, sb);
80        sb.append("</record>").append(nl);
81        return sb.toString();
82    }
83
84    private void formatMessages(LogRecord r, StringBuilder sb) {
85        // get localized message if has, but don't call Formatter.formatMessage
86        // to parse pattern string
87        ResourceBundle rb = r.getResourceBundle();
88        String pattern = r.getMessage();
89        if (rb != null && pattern != null) {
90            String message;
91            try {
92                message = rb.getString(pattern);
93            } catch (Exception e) {
94                message = null;
95            }
96
97            if (message == null) {
98                message = pattern;
99                append(sb, 1, "message", message);
100            } else {
101                append(sb, 1, "message", message);
102                append(sb, 1, "key", pattern);
103                append(sb, 1, "catalog", r.getResourceBundleName());
104            }
105        } else if (pattern != null) {
106            append(sb, 1, "message", pattern);
107        } else {
108            sb.append(indent).append("<message/>");
109        }
110    }
111
112    private void formatThrowable(LogRecord r, StringBuilder sb) {
113        Throwable t;
114        if ((t = r.getThrown()) != null) {
115            String nl = System.lineSeparator();
116            sb.append(indent).append("<exception>").append(nl);
117            append(sb, 2, "message", t.toString());
118            // format throwable's stack trace
119            StackTraceElement[] elements = t.getStackTrace();
120            for (StackTraceElement e : elements) {
121                sb.append(indent).append(indent).append("<frame>").append(nl);
122                append(sb, 3, "class", e.getClassName());
123                append(sb, 3, "method", e.getMethodName());
124                append(sb, 3, "line", e.getLineNumber());
125                sb.append(indent).append(indent).append("</frame>").append(nl);
126            }
127            sb.append(indent).append("</exception>").append(nl);
128        }
129    }
130
131    private static void append(StringBuilder sb, int indentCount, String tag, Object value) {
132        for (int i = 0; i < indentCount; ++i) {
133            sb.append(indent);
134        }
135        sb.append("<").append(tag).append(">");
136        sb.append(value);
137        sb.append("</").append(tag).append(">");
138        sb.append(System.lineSeparator());
139    }
140
141    /**
142     * Returns the header string for a set of log records formatted as XML
143     * strings, using the output handler's encoding if it is defined, otherwise
144     * using the default platform encoding.
145     *
146     * @param h
147     *            the output handler, may be {@code null}.
148     * @return the header string for log records formatted as XML strings.
149     */
150    @Override
151    public String getHead(Handler h) {
152        String encoding = null;
153        if (h != null) {
154            encoding = h.getEncoding();
155        }
156        if (encoding == null) {
157            encoding = System.getProperty("file.encoding");
158        }
159        StringBuilder sb = new StringBuilder();
160        sb.append("<?xml version=\"1.0\" encoding=\"").append(encoding).append("\" standalone=\"no\"?>");
161        sb.append(System.lineSeparator());
162        sb.append("<!DOCTYPE log SYSTEM \"logger.dtd\">");
163        sb.append(System.lineSeparator());
164        sb.append("<log>");
165        return sb.toString();
166    }
167
168    /**
169     * Returns the tail string for a set of log records formatted as XML
170     * strings.
171     *
172     * @param h
173     *            the output handler, may be {@code null}.
174     * @return the tail string for log records formatted as XML strings.
175     */
176    @Override
177    public String getTail(Handler h) {
178        return "</log>";
179    }
180}
181