org.apache.logging.log4j.message.ParameterizedMessage Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.message;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Collection;
import java.util.Date;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
* Handles messages that consist of a format string containing '{}' to represent each replaceable token, and
* the parameters.
*
* This class was originally written for Lilith by Joern Huxhorn where it is
* licensed under the LGPL. It has been relicensed here with his permission providing that this attribution remain.
*
*/
public class ParameterizedMessage implements Message {
/**
* Prefix for recursion.
*/
public static final String RECURSION_PREFIX = "[...";
/**
* Suffix for recursion.
*/
public static final String RECURSION_SUFFIX = "...]";
/**
* Prefix for errors.
*/
public static final String ERROR_PREFIX = "[!!!";
/**
* Separator for errors.
*/
public static final String ERROR_SEPARATOR = "=>";
/**
* Separator for error messages.
*/
public static final String ERROR_MSG_SEPARATOR = ":";
/**
* Suffix for errors.
*/
public static final String ERROR_SUFFIX = "!!!]";
private static final long serialVersionUID = -665975803997290697L;
private static final int HASHVAL = 31;
private static final char DELIM_START = '{';
private static final char DELIM_STOP = '}';
private static final char ESCAPE_CHAR = '\\';
private final String messagePattern;
private final String[] stringArgs;
private transient Object[] argArray;
private transient String formattedMessage;
private transient Throwable throwable;
/**
* Creates a parameterized message.
* @param messagePattern The message "format" string. This will be a String containing "{}" placeholders
* where parameters should be substituted.
* @param stringArgs The arguments for substitution.
* @param throwable A Throwable.
*/
public ParameterizedMessage(final String messagePattern, final String[] stringArgs, final Throwable throwable) {
this.messagePattern = messagePattern;
this.stringArgs = stringArgs;
this.throwable = throwable;
}
/**
* Creates a parameterized message.
* @param messagePattern The message "format" string. This will be a String containing "{}" placeholders
* where parameters should be substituted.
* @param objectArgs The arguments for substitution.
* @param throwable A Throwable.
*/
public ParameterizedMessage(final String messagePattern, final Object[] objectArgs, final Throwable throwable) {
this.messagePattern = messagePattern;
this.throwable = throwable;
this.stringArgs = argumentsToStrings(objectArgs);
}
/**
* Constructs a ParameterizedMessage which contains the arguments converted to String as well as an optional
* Throwable.
*
* If the last argument is a Throwable and is NOT used up by a placeholder in the message pattern it is returned
* in {@link #getThrowable()} and won't be contained in the created String[].
* If it is used up {@link #getThrowable()} will return null even if the last argument was a Throwable!
*
* @param messagePattern the message pattern that to be checked for placeholders.
* @param arguments the argument array to be converted.
*/
public ParameterizedMessage(final String messagePattern, final Object[] arguments) {
this.messagePattern = messagePattern;
this.stringArgs = argumentsToStrings(arguments);
}
/**
* Constructor with a pattern and a single parameter.
* @param messagePattern The message pattern.
* @param arg The parameter.
*/
public ParameterizedMessage(final String messagePattern, final Object arg) {
this(messagePattern, new Object[]{arg});
}
/**
* Constructor with a pattern and two parameters.
* @param messagePattern The message pattern.
* @param arg1 The first parameter.
* @param arg2 The second parameter.
*/
public ParameterizedMessage(final String messagePattern, final Object arg1, final Object arg2) {
this(messagePattern, new Object[]{arg1, arg2});
}
private String[] argumentsToStrings(final Object[] arguments) {
if (arguments == null) {
return null;
}
final int argsCount = countArgumentPlaceholders(messagePattern);
int resultArgCount = arguments.length;
if (argsCount < arguments.length && throwable == null && arguments[arguments.length - 1] instanceof Throwable) {
throwable = (Throwable) arguments[arguments.length - 1];
resultArgCount--;
}
argArray = new Object[resultArgCount];
System.arraycopy(arguments, 0, argArray, 0, resultArgCount);
String[] strArgs;
if (argsCount == 1 && throwable == null && arguments.length > 1) {
// special case
strArgs = new String[1];
strArgs[0] = deepToString(arguments);
} else {
strArgs = new String[resultArgCount];
for (int i = 0; i < strArgs.length; i++) {
strArgs[i] = deepToString(arguments[i]);
}
}
return strArgs;
}
/**
* Returns the formatted message.
* @return the formatted message.
*/
@Override
public String getFormattedMessage() {
if (formattedMessage == null) {
formattedMessage = formatMessage(messagePattern, stringArgs);
}
return formattedMessage;
}
/**
* Returns the message pattern.
* @return the message pattern.
*/
@Override
public String getFormat() {
return messagePattern;
}
/**
* Returns the message parameters.
* @return the message parameters.
*/
@Override
public Object[] getParameters() {
if (argArray != null) {
return argArray;
}
return stringArgs;
}
/**
* Returns the Throwable that was given as the last argument, if any.
* It will not survive serialization. The Throwable exists as part of the message
* primarily so that it can be extracted from the end of the list of parameters
* and then be added to the LogEvent. As such, the Throwable in the event should
* not be used once the LogEvent has been constructed.
*
* @return the Throwable, if any.
*/
@Override
public Throwable getThrowable() {
return throwable;
}
protected String formatMessage(final String msgPattern, final String[] sArgs) {
return format(msgPattern, sArgs);
}
@Override
public boolean equals(final Object o) {
if (this == o) {
return true;
}
if (o == null || getClass() != o.getClass()) {
return false;
}
final ParameterizedMessage that = (ParameterizedMessage) o;
if (messagePattern != null ? !messagePattern.equals(that.messagePattern) : that.messagePattern != null) {
return false;
}
if (!Arrays.equals(stringArgs, that.stringArgs)) {
return false;
}
//if (throwable != null ? !throwable.equals(that.throwable) : that.throwable != null) return false;
return true;
}
@Override
public int hashCode() {
int result = messagePattern != null ? messagePattern.hashCode() : 0;
result = HASHVAL * result + (stringArgs != null ? Arrays.hashCode(stringArgs) : 0);
return result;
}
/**
* Replace placeholders in the given messagePattern with arguments.
*
* @param messagePattern the message pattern containing placeholders.
* @param arguments the arguments to be used to replace placeholders.
* @return the formatted message.
*/
public static String format(final String messagePattern, final Object[] arguments) {
if (messagePattern == null || arguments == null || arguments.length == 0) {
return messagePattern;
}
final StringBuilder result = new StringBuilder();
int escapeCounter = 0;
int currentArgument = 0;
for (int i = 0; i < messagePattern.length(); i++) {
final char curChar = messagePattern.charAt(i);
if (curChar == ESCAPE_CHAR) {
escapeCounter++;
} else {
if (curChar == DELIM_START && i < messagePattern.length() - 1
&& messagePattern.charAt(i + 1) == DELIM_STOP) {
// write escaped escape chars
final int escapedEscapes = escapeCounter / 2;
for (int j = 0; j < escapedEscapes; j++) {
result.append(ESCAPE_CHAR);
}
if (escapeCounter % 2 == 1) {
// i.e. escaped
// write escaped escape chars
result.append(DELIM_START);
result.append(DELIM_STOP);
} else {
// unescaped
if (currentArgument < arguments.length) {
result.append(arguments[currentArgument]);
} else {
result.append(DELIM_START).append(DELIM_STOP);
}
currentArgument++;
}
i++;
escapeCounter = 0;
continue;
}
// any other char beside ESCAPE or DELIM_START/STOP-combo
// write unescaped escape chars
if (escapeCounter > 0) {
for (int j = 0; j < escapeCounter; j++) {
result.append(ESCAPE_CHAR);
}
escapeCounter = 0;
}
result.append(curChar);
}
}
return result.toString();
}
/**
* Counts the number of unescaped placeholders in the given messagePattern.
*
* @param messagePattern the message pattern to be analyzed.
* @return the number of unescaped placeholders.
*/
public static int countArgumentPlaceholders(final String messagePattern) {
if (messagePattern == null) {
return 0;
}
final int delim = messagePattern.indexOf(DELIM_START);
if (delim == -1) {
// special case, no placeholders at all.
return 0;
}
int result = 0;
boolean isEscaped = false;
for (int i = 0; i < messagePattern.length(); i++) {
final char curChar = messagePattern.charAt(i);
if (curChar == ESCAPE_CHAR) {
isEscaped = !isEscaped;
} else if (curChar == DELIM_START) {
if (!isEscaped && i < messagePattern.length() - 1 && messagePattern.charAt(i + 1) == DELIM_STOP) {
result++;
i++;
}
isEscaped = false;
} else {
isEscaped = false;
}
}
return result;
}
/**
* This method performs a deep toString of the given Object.
* Primitive arrays are converted using their respective Arrays.toString methods while
* special handling is implemented for "container types", i.e. Object[], Map and Collection because those could
* contain themselves.
*
* It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a
* behavior. They only check if the container is directly contained in itself, but not if a contained container
* contains the original one. Because of that, Arrays.toString(Object[]) isn't safe either.
* Confusing? Just read the last paragraph again and check the respective toString() implementation.
*
*
* This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o)
* would produce a relatively hard-to-debug StackOverflowError.
*
* @param o The object.
* @return The String representation.
*/
public static String deepToString(final Object o) {
if (o == null) {
return null;
}
if (o instanceof String) {
return (String) o;
}
final StringBuilder str = new StringBuilder();
final Set dejaVu = new HashSet(); // that's actually a neat name ;)
recursiveDeepToString(o, str, dejaVu);
return str.toString();
}
/**
* This method performs a deep toString of the given Object.
* Primitive arrays are converted using their respective Arrays.toString methods while
* special handling is implemented for "container types", i.e. Object[], Map and Collection because those could
* contain themselves.
*
* dejaVu is used in case of those container types to prevent an endless recursion.
*
*
* It should be noted that neither AbstractMap.toString() nor AbstractCollection.toString() implement such a
* behavior.
* They only check if the container is directly contained in itself, but not if a contained container contains the
* original one. Because of that, Arrays.toString(Object[]) isn't safe either.
* Confusing? Just read the last paragraph again and check the respective toString() implementation.
*
*
* This means, in effect, that logging would produce a usable output even if an ordinary System.out.println(o)
* would produce a relatively hard-to-debug StackOverflowError.
*
*
* @param o the Object to convert into a String
* @param str the StringBuilder that o will be appended to
* @param dejaVu a list of container identities that were already used.
*/
private static void recursiveDeepToString(final Object o, final StringBuilder str, final Set dejaVu) {
if (o == null) {
str.append("null");
return;
}
if (o instanceof String) {
str.append(o);
return;
}
final Class oClass = o.getClass();
if (oClass.isArray()) {
if (oClass == byte[].class) {
str.append(Arrays.toString((byte[]) o));
} else if (oClass == short[].class) {
str.append(Arrays.toString((short[]) o));
} else if (oClass == int[].class) {
str.append(Arrays.toString((int[]) o));
} else if (oClass == long[].class) {
str.append(Arrays.toString((long[]) o));
} else if (oClass == float[].class) {
str.append(Arrays.toString((float[]) o));
} else if (oClass == double[].class) {
str.append(Arrays.toString((double[]) o));
} else if (oClass == boolean[].class) {
str.append(Arrays.toString((boolean[]) o));
} else if (oClass == char[].class) {
str.append(Arrays.toString((char[]) o));
} else {
// special handling of container Object[]
final String id = identityToString(o);
if (dejaVu.contains(id)) {
str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
} else {
dejaVu.add(id);
final Object[] oArray = (Object[]) o;
str.append('[');
boolean first = true;
for (final Object current : oArray) {
if (first) {
first = false;
} else {
str.append(", ");
}
recursiveDeepToString(current, str, new HashSet(dejaVu));
}
str.append(']');
}
//str.append(Arrays.deepToString((Object[]) o));
}
} else if (o instanceof Map) {
// special handling of container Map
final String id = identityToString(o);
if (dejaVu.contains(id)) {
str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
} else {
dejaVu.add(id);
final Map oMap = (Map) o;
str.append('{');
boolean isFirst = true;
for (final Object o1 : oMap.entrySet()) {
final Map.Entry current = (Map.Entry) o1;
if (isFirst) {
isFirst = false;
} else {
str.append(", ");
}
final Object key = current.getKey();
final Object value = current.getValue();
recursiveDeepToString(key, str, new HashSet(dejaVu));
str.append('=');
recursiveDeepToString(value, str, new HashSet(dejaVu));
}
str.append('}');
}
} else if (o instanceof Collection) {
// special handling of container Collection
final String id = identityToString(o);
if (dejaVu.contains(id)) {
str.append(RECURSION_PREFIX).append(id).append(RECURSION_SUFFIX);
} else {
dejaVu.add(id);
final Collection oCol = (Collection) o;
str.append('[');
boolean isFirst = true;
for (final Object anOCol : oCol) {
if (isFirst) {
isFirst = false;
} else {
str.append(", ");
}
recursiveDeepToString(anOCol, str, new HashSet(dejaVu));
}
str.append(']');
}
} else if (o instanceof Date) {
final Date date = (Date) o;
final SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSZ");
// I'll leave it like this for the moment... this could probably be optimized using ThreadLocal...
str.append(format.format(date));
} else {
// it's just some other Object, we can only use toString().
try {
str.append(o.toString());
} catch (final Throwable t) {
str.append(ERROR_PREFIX);
str.append(identityToString(o));
str.append(ERROR_SEPARATOR);
final String msg = t.getMessage();
final String className = t.getClass().getName();
str.append(className);
if (!className.equals(msg)) {
str.append(ERROR_MSG_SEPARATOR);
str.append(msg);
}
str.append(ERROR_SUFFIX);
}
}
}
/**
* This method returns the same as if Object.toString() would not have been
* overridden in obj.
*
* Note that this isn't 100% secure as collisions can always happen with hash codes.
*
*
* Copied from Object.hashCode():
*
*
* As much as is reasonably practical, the hashCode method defined by
* class {@code Object} does return distinct integers for distinct
* objects. (This is typically implemented by converting the internal
* address of the object into an integer, but this implementation
* technique is not required by the Java™ programming language.)
*
*
* @param obj the Object that is to be converted into an identity string.
* @return the identity string as also defined in Object.toString()
*/
public static String identityToString(final Object obj) {
if (obj == null) {
return null;
}
return obj.getClass().getName() + '@' + Integer.toHexString(System.identityHashCode(obj));
}
@Override
public String toString() {
return "ParameterizedMessage[messagePattern=" + messagePattern + ", stringArgs=" +
Arrays.toString(stringArgs) + ", throwable=" + throwable + ']';
}
}