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/*
* Copyright (c) 2004-2005 SLF4J.ORG
* Copyright (c) 2004-2005 QOS.ch
*
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
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* to whom the Software is furnished to do so, provided that the above
* copyright notice(s) and this permission notice appear in all copies of
* the Software and that both the above copyright notice(s) and this
* permission notice appear in supporting documentation.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
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package org.slf4j.impl;
/**
* Formats messages according to very simple substitution rules. Substitutions can be
* made 1, 2 or more arguments.
*
* For example,
*
MessageFormatter.format("Hi {}.", "there"); will
* return the string "Hi there.".
*
* The {} pair is called the formatting anchor. It serves to designate the
* location where arguments need to be substituted within the message pattern.
*
* In the rare case where you need to place the '{' or '}' in the message pattern
* itself but do not want them to be interpreted as a formatting anchors, you can
* espace the '{' character with '\', that is the backslash character. Only the
* '{' character should be escaped. There is no need to escape the '}' character.
* For example,
MessageFormatter.format("File name is \\{{}}.", "App folder.zip");
* will return the string "File name is {App folder.zip}.".
*
* See {@link #format(String, Object)}, {@link #format(String, Object, Object)}
* and {@link #arrayFormat(String, Object[])} methods for more details.
*
* @author Ceki Gülcü
*/
public class MessageFormatter {
static final char DELIM_START = '{';
static final char DELIM_STOP = '}';
/**
* Performs single argument substitution for the 'messagePattern' passed as
* parameter.
*
* For example,
MessageFormatter.format("Hi {}.", "there"); will
* return the string "Hi there.".
*
* @param messagePattern The message pattern which will be parsed and formatted
* @param argument The argument to be substituted in place of the formatting anchor
* @return The formatted message
*/
public static String format(String messagePattern, Object arg) {
return arrayFormat(messagePattern, new Object[] {arg});
}
/**
*
* Performs a two argument substitution for the 'messagePattern' passed as
* parameter.
*
* For example,
*
MessageFormatter.format("Hi {}. My name is {}.", "Alice", "Bob"); will
* return the string "Hi Alice. My name is Bob.".
*
* @param messagePattern The message pattern which will be parsed and formatted
* @param arg1 The argument to be substituted in place of the first formatting anchor
* @param arg2 The argument to be substituted in place of the second formatting anchor
* @return The formatted message
*/
public static String format(String messagePattern, Object arg1, Object arg2) {
return arrayFormat(messagePattern, new Object[] {arg1, arg2});
}
/**
* Same principle as the {@link #format(String, Object)} and
* {@link #format(String, Object, Object)} methods except that
* any number of arguments can be passed in an array.
*
* @param messagePattern The message pattern which will be parsed and formatted
* @param argArray An array of arguments to be substituted in place of formatting anchors
* @return The formatted message
*/
public static String arrayFormat(String messagePattern, Object[] argArray) {
if(messagePattern == null) {
return null;
}
int i = 0;
int len = messagePattern.length();
int j = messagePattern.indexOf(DELIM_START);
StringBuffer sbuf = new StringBuffer(messagePattern.length() + 50);
for (int L = 0; L < argArray.length; L++) {
char escape = 'x';
j = messagePattern.indexOf(DELIM_START, i);
if (j == -1 || (j+1 == len)) {
// no more variables
if (i == 0) { // this is a simple string
return messagePattern;
} else { // add the tail string which contains no variables and return the result.
sbuf.append(messagePattern.substring(i, messagePattern.length()));
return sbuf.toString();
}
} else {
char delimStop = messagePattern.charAt(j + 1);
if (j > 0) {
escape = messagePattern.charAt(j - 1);
}
if(escape == '\\') {
L--; // DELIM_START was escaped, thus should not be incremented
sbuf.append(messagePattern.substring(i, j-1));
sbuf.append(DELIM_START);
i = j + 1;
} else if ((delimStop != DELIM_STOP)) {
// invalid DELIM_START/DELIM_STOP pair
sbuf.append(messagePattern.substring(i, messagePattern.length()));
return sbuf.toString();
} else {
// normal case
sbuf.append(messagePattern.substring(i, j));
sbuf.append(argArray[L]);
i = j + 2;
}
}
}
// append the characters following the second {} pair.
sbuf.append(messagePattern.substring(i, messagePattern.length()));
return sbuf.toString();
}
}