View Javadoc

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  package org.apache.logging.log4j.message;
18  
19  import java.text.SimpleDateFormat;
20  import java.util.Arrays;
21  import java.util.Collection;
22  import java.util.Date;
23  import java.util.HashSet;
24  import java.util.Map;
25  import java.util.Set;
26  
27  /**
28   * Handles messages that consist of a format string containing '{}' to represent each replaceable token, and
29   * the parameters.
30   * <p/>
31   * This class was originally written for Lillith (http://mac.freshmeat.net/projects/lilith-viewer) by
32   * Joern Huxhorn where it is licensed under the LGPL. It has been relicensed here with his permission
33   * providing that this attribution remain.
34   */
35  public class ParameterizedMessage implements Message {
36  
37      /**
38       * Prefix for recursion.
39       */
40      public static final String RECURSION_PREFIX = "[...";
41      /**
42       * Suffix for recursion.
43       */
44      public static final String RECURSION_SUFFIX = "...]";
45  
46      /**
47       * Prefix for errors.
48       */
49      public static final String ERROR_PREFIX = "[!!!";
50      /**
51       * Separator for errors.
52       */
53      public static final String ERROR_SEPARATOR = "=>";
54      /**
55       * Separator for error messages.
56       */
57      public static final String ERROR_MSG_SEPARATOR = ":";
58      /**
59       * Suffix for errors.
60       */
61      public static final String ERROR_SUFFIX = "!!!]";
62  
63      private static final long serialVersionUID = -665975803997290697L;
64  
65      private static final int HASHVAL = 31;
66  
67      private static final char DELIM_START = '{';
68      private static final char DELIM_STOP = '}';
69      private static final char ESCAPE_CHAR = '\\';
70  
71      private final String messagePattern;
72      private final String[] stringArgs;
73      private transient Object[] argArray;
74      private transient String formattedMessage;
75      private transient Throwable throwable;
76  
77      /**
78       * Creates a parameterized message.
79       * @param messagePattern The message "format" string. This will be a String containing "{}" placeholders
80       * where parameters should be substituted.
81       * @param stringArgs The arguments for substitution.
82       * @param throwable A Throwable.
83       */
84      public ParameterizedMessage(final String messagePattern, final String[] stringArgs, final Throwable throwable) {
85          this.messagePattern = messagePattern;
86          this.stringArgs = stringArgs;
87          this.throwable = throwable;
88      }
89  
90      /**
91       * Creates a parameterized message.
92       * @param messagePattern The message "format" string. This will be a String containing "{}" placeholders
93       * where parameters should be substituted.
94       * @param objectArgs The arguments for substitution.
95       * @param throwable A Throwable.
96       */
97      public ParameterizedMessage(final String messagePattern, final Object[] objectArgs, final Throwable throwable) {
98          this.messagePattern = messagePattern;
99          this.throwable = throwable;
100         this.stringArgs = parseArguments(objectArgs);
101     }
102 
103     /**
104      * <p>This method returns a ParameterizedMessage which contains the arguments converted to String
105      * as well as an optional Throwable.</p>
106      * <p/>
107      * <p>If the last argument is a Throwable and is NOT used up by a placeholder in the message pattern it is returned
108      * in ParameterizedMessage.getThrowable() and won't be contained in the created String[].<br/>
109      * If it is used up ParameterizedMessage.getThrowable() will return null even if the last argument was a
110      * Throwable!</p>
111      *
112      * @param messagePattern the message pattern that to be checked for placeholders.
113      * @param arguments      the argument array to be converted.
114      */
115     public ParameterizedMessage(final String messagePattern, final Object[] arguments) {
116         this.messagePattern = messagePattern;
117         this.stringArgs = parseArguments(arguments);
118     }
119 
120     /**
121      * Constructor with a pattern and a single parameter.
122      * @param messagePattern The message pattern.
123      * @param arg The parameter.
124      */
125     public ParameterizedMessage(final String messagePattern, final Object arg) {
126         this(messagePattern, new Object[]{arg});
127     }
128 
129     /**
130      * Constructor with a pattern and two parameters.
131      * @param messagePattern The message pattern.
132      * @param arg1 The first parameter.
133      * @param arg2 The second parameter.
134      */
135     public ParameterizedMessage(final String messagePattern, final Object arg1, final Object arg2) {
136         this(messagePattern, new Object[]{arg1, arg2});
137     }
138 
139     private String[] parseArguments(final Object[] arguments) {
140         if (arguments == null) {
141             return null;
142         }
143         final int argsCount = countArgumentPlaceholders(messagePattern);
144         int resultArgCount = arguments.length;
145         if (argsCount < arguments.length && throwable == null && arguments[arguments.length - 1] instanceof Throwable) {
146             throwable = (Throwable) arguments[arguments.length - 1];
147             resultArgCount--;
148         }
149         argArray = new Object[resultArgCount];
150         for (int i = 0; i < resultArgCount; ++i) {
151             argArray[i] = arguments[i];
152         }
153 
154         String[] strArgs;
155         if (argsCount == 1 && throwable == null && arguments.length > 1) {
156             // special case
157             strArgs = new String[1];
158             strArgs[0] = deepToString(arguments);
159         } else {
160             strArgs = new String[resultArgCount];
161             for (int i = 0; i < strArgs.length; i++) {
162                 strArgs[i] = deepToString(arguments[i]);
163             }
164         }
165         return strArgs;
166     }
167 
168     /**
169      * Returns the formatted message.
170      * @return the formatted message.
171      */
172     @Override
173     public String getFormattedMessage() {
174         if (formattedMessage == null) {
175             formattedMessage = formatMessage(messagePattern, stringArgs);
176         }
177         return formattedMessage;
178     }
179 
180     /**
181      * Returns the message pattern.
182      * @return the message pattern.
183      */
184     @Override
185     public String getFormat() {
186         return messagePattern;
187     }
188 
189     /**
190      * Returns the message parameters.
191      * @return the message parameters.
192      */
193     @Override
194     public Object[] getParameters() {
195         if (argArray != null) {
196             return argArray;
197         }
198         return stringArgs;
199     }
200 
201     /**
202      * Returns the Throwable that was given as the last argument, if any.
203      * It will not survive serialization. The Throwable exists as part of the message
204      * primarily so that it can be extracted from the end of the list of parameters
205      * and then be added to the LogEvent. As such, the Throwable in the event should
206      * not be used once the LogEvent has been constructed.
207      *
208      * @return the Throwable, if any.
209      */
210     @Override
211     public Throwable getThrowable() {
212         return throwable;
213     }
214 
215     protected String formatMessage(final String msgPattern, final String[] sArgs) {
216         return format(msgPattern, sArgs);
217     }
218 
219     @Override
220     public boolean equals(final Object o) {
221         if (this == o) {
222             return true;
223         }
224         if (o == null || getClass() != o.getClass()) {
225             return false;
226         }
227 
228         final ParameterizedMessage that = (ParameterizedMessage) o;
229 
230         if (messagePattern != null ? !messagePattern.equals(that.messagePattern) : that.messagePattern != null) {
231             return false;
232         }
233         if (!Arrays.equals(stringArgs, that.stringArgs)) {
234             return false;
235         }
236         //if (throwable != null ? !throwable.equals(that.throwable) : that.throwable != null) return false;
237 
238         return true;
239     }
240 
241     @Override
242     public int hashCode() {
243         int result = messagePattern != null ? messagePattern.hashCode() : 0;
244         result = HASHVAL * result + (stringArgs != null ? Arrays.hashCode(stringArgs) : 0);
245         return result;
246     }
247 
248     /**
249      * Replace placeholders in the given messagePattern with arguments.
250      *
251      * @param messagePattern the message pattern containing placeholders.
252      * @param arguments      the arguments to be used to replace placeholders.
253      * @return the formatted message.
254      */
255     public static String format(final String messagePattern, final Object[] arguments) {
256         if (messagePattern == null || arguments == null || arguments.length == 0) {
257             return messagePattern;
258         }
259 
260         final StringBuilder result = new StringBuilder();
261         int escapeCounter = 0;
262         int currentArgument = 0;
263         for (int i = 0; i < messagePattern.length(); i++) {
264             final char curChar = messagePattern.charAt(i);
265             if (curChar == ESCAPE_CHAR) {
266                 escapeCounter++;
267             } else {
268                 if (curChar == DELIM_START && i < messagePattern.length() - 1
269                         && messagePattern.charAt(i + 1) == DELIM_STOP) {
270                     // write escaped escape chars
271                     final int escapedEscapes = escapeCounter / 2;
272                     for (int j = 0; j < escapedEscapes; j++) {
273                         result.append(ESCAPE_CHAR);
274                     }
275 
276                     if (escapeCounter % 2 == 1) {
277                         // i.e. escaped
278                         // write escaped escape chars
279                         result.append(DELIM_START);
280                         result.append(DELIM_STOP);
281                     } else {
282                         // unescaped
283                         if (currentArgument < arguments.length) {
284                             result.append(arguments[currentArgument]);
285                         } else {
286                             result.append(DELIM_START).append(DELIM_STOP);
287                         }
288                         currentArgument++;
289                     }
290                     i++;
291                     escapeCounter = 0;
292                     continue;
293                 }
294                 // any other char beside ESCAPE or DELIM_START/STOP-combo
295                 // write unescaped escape chars
296                 if (escapeCounter > 0) {
297                     for (int j = 0; j < escapeCounter; j++) {
298                         result.append(ESCAPE_CHAR);
299                     }
300                     escapeCounter = 0;
301                 }
302                 result.append(curChar);
303             }
304         }
305         return result.toString();
306     }
307 
308     /**
309      * Counts the number of unescaped placeholders in the given messagePattern.
310      *
311      * @param messagePattern the message pattern to be analyzed.
312      * @return the number of unescaped placeholders.
313      */
314     public static int countArgumentPlaceholders(final String messagePattern) {
315         if (messagePattern == null) {
316             return 0;
317         }
318 
319         final int delim = messagePattern.indexOf(DELIM_START);
320 
321         if (delim == -1) {
322             // special case, no placeholders at all.
323             return 0;
324         }
325         int result = 0;
326         boolean isEscaped = false;
327         for (int i = 0; i < messagePattern.length(); i++) {
328             final char curChar = messagePattern.charAt(i);
329             if (curChar == ESCAPE_CHAR) {
330                 isEscaped = !isEscaped;
331             } else if (curChar == DELIM_START) {
332                 if (!isEscaped && i < messagePattern.length() - 1 && messagePattern.charAt(i + 1) == DELIM_STOP) {
333                     result++;
334                     i++;
335                 }
336                 isEscaped = false;
337             } else {
338                 isEscaped = false;
339             }
340         }
341         return result;
342     }
343 
344     /**
345      * This method performs a deep toString of the given Object.
346      * Primitive arrays are converted using their respective Arrays.toString methods while
347      * special handling is implemented for "container types", i.e. Object[], Map and Collection because those could
348      * contain themselves.
349      * <p/>
350      * It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a
351      * behavior. They only check if the container is directly contained in itself, but not if a contained container
352      * contains the original one. Because of that, Arrays.toString(Object[]) isn't safe either.
353      * Confusing? Just read the last paragraph again and check the respective toString() implementation.
354      * <p/>
355      * This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o)
356      * would produce a relatively hard-to-debug StackOverflowError.
357      * @param o The object.
358      * @return The String representation.
359      */
360     public static String deepToString(final Object o) {
361         if (o == null) {
362             return null;
363         }
364         if (o instanceof String) {
365             return (String) o;
366         }
367         final StringBuilder str = new StringBuilder();
368         final Set<String> dejaVu = new HashSet<String>(); // that's actually a neat name ;)
369         recursiveDeepToString(o, str, dejaVu);
370         return str.toString();
371     }
372 
373     /**
374      * This method performs a deep toString of the given Object.
375      * Primitive arrays are converted using their respective Arrays.toString methods while
376      * special handling is implemented for "container types", i.e. Object[], Map and Collection because those could
377      * contain themselves.
378      * <p/>
379      * dejaVu is used in case of those container types to prevent an endless recursion.
380      * <p/>
381      * It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a
382      * behavior.
383      * They only check if the container is directly contained in itself, but not if a contained container contains the
384      * original one. Because of that, Arrays.toString(Object[]) isn't safe either.
385      * Confusing? Just read the last paragraph again and check the respective toString() implementation.
386      * <p/>
387      * This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o)
388      * would produce a relatively hard-to-debug StackOverflowError.
389      *
390      * @param o      the Object to convert into a String
391      * @param str    the StringBuilder that o will be appended to
392      * @param dejaVu a list of container identities that were already used.
393      */
394     private static void recursiveDeepToString(final Object o, final StringBuilder str, final Set<String> dejaVu) {
395         if (o == null) {
396             str.append("null");
397             return;
398         }
399         if (o instanceof String) {
400             str.append(o);
401             return;
402         }
403 
404         final Class<?> oClass = o.getClass();
405         if (oClass.isArray()) {
406             if (oClass == byte[].class) {
407                 str.append(Arrays.toString((byte[]) o));
408             } else if (oClass == short[].class) {
409                 str.append(Arrays.toString((short[]) o));
410             } else if (oClass == int[].class) {
411                 str.append(Arrays.toString((int[]) o));
412             } else if (oClass == long[].class) {
413                 str.append(Arrays.toString((long[]) o));
414             } else if (oClass == float[].class) {
415                 str.append(Arrays.toString((float[]) o));
416             } else if (oClass == double[].class) {
417                 str.append(Arrays.toString((double[]) o));
418             } else if (oClass == boolean[].class) {
419                 str.append(Arrays.toString((boolean[]) o));
420             } else if (oClass == char[].class) {
421                 str.append(Arrays.toString((char[]) o));
422             } else {
423                 // special handling of container Object[]
424                 final String id = identityToString(o);
425                 if (dejaVu.contains(id)) {
426                     str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
427                 } else {
428                     dejaVu.add(id);
429                     final Object[] oArray = (Object[]) o;
430                     str.append('[');
431                     boolean first = true;
432                     for (final Object current : oArray) {
433                         if (first) {
434                             first = false;
435                         } else {
436                             str.append(", ");
437                         }
438                         recursiveDeepToString(current, str, new HashSet<String>(dejaVu));
439                     }
440                     str.append(']');
441                 }
442                 //str.append(Arrays.deepToString((Object[]) o));
443             }
444         } else if (o instanceof Map) {
445             // special handling of container Map
446             final String id = identityToString(o);
447             if (dejaVu.contains(id)) {
448                 str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
449             } else {
450                 dejaVu.add(id);
451                 final Map<?, ?> oMap = (Map<?, ?>) o;
452                 str.append('{');
453                 boolean isFirst = true;
454                 for (final Object o1 : oMap.entrySet()) {
455                     final Map.Entry<?, ?> current = (Map.Entry<?, ?>) o1;
456                     if (isFirst) {
457                         isFirst = false;
458                     } else {
459                         str.append(", ");
460                     }
461                     final Object key = current.getKey();
462                     final Object value = current.getValue();
463                     recursiveDeepToString(key, str, new HashSet<String>(dejaVu));
464                     str.append('=');
465                     recursiveDeepToString(value, str, new HashSet<String>(dejaVu));
466                 }
467                 str.append('}');
468             }
469         } else if (o instanceof Collection) {
470             // special handling of container Collection
471             final String id = identityToString(o);
472             if (dejaVu.contains(id)) {
473                 str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
474             } else {
475                 dejaVu.add(id);
476                 final Collection<?> oCol = (Collection<?>) o;
477                 str.append('[');
478                 boolean isFirst = true;
479                 for (final Object anOCol : oCol) {
480                     if (isFirst) {
481                         isFirst = false;
482                     } else {
483                         str.append(", ");
484                     }
485                     recursiveDeepToString(anOCol, str, new HashSet<String>(dejaVu));
486                 }
487                 str.append(']');
488             }
489         } else if (o instanceof Date) {
490             final Date date = (Date) o;
491             final SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
492             // I'll leave it like this for the moment... this could probably be optimized using ThreadLocal...
493             str.append(format.format(date));
494         } else {
495             // it's just some other Object, we can only use toString().
496             try {
497                 str.append(o.toString());
498             } catch (final Throwable t) {
499                 str.append(ERROR_PREFIX);
500                 str.append(identityToString(o));
501                 str.append(ERROR_SEPARATOR);
502                 final String msg = t.getMessage();
503                 final String className = t.getClass().getName();
504                 str.append(className);
505                 if (!className.equals(msg)) {
506                     str.append(ERROR_MSG_SEPARATOR);
507                     str.append(msg);
508                 }
509                 str.append(ERROR_SUFFIX);
510             }
511         }
512     }
513 
514     /**
515      * This method returns the same as if Object.toString() would not have been
516      * overridden in obj.
517      * <p/>
518      * Note that this isn't 100% secure as collisions can always happen with hash codes.
519      * <p/>
520      * Copied from Object.hashCode():
521      * As much as is reasonably practical, the hashCode method defined by
522      * class <tt>Object</tt> does return distinct integers for distinct
523      * objects. (This is typically implemented by converting the internal
524      * address of the object into an integer, but this implementation
525      * technique is not required by the
526      * Java<font size="-2"><sup>TM</sup></font>
527      * programming language.)
528      *
529      * @param obj the Object that is to be converted into an identity string.
530      * @return the identity string as also defined in Object.toString()
531      */
532     public static String identityToString(final Object obj) {
533         if (obj == null) {
534             return null;
535         }
536         return obj.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(obj));
537     }
538 
539     @Override
540     public String toString() {
541         return "ParameterizedMessage[messagePattern=" + messagePattern + ", stringArgs=" +
542             Arrays.toString(stringArgs) + ", throwable=" + throwable + ']';
543     }
544 }