org.apache.log4j.helpers.MessageFormatter Maven / Gradle / Ivy
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/*
* Copyright 1999,2005 The Apache Software Foundation.
*
* Licensed 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.log4j.helpers;
/**
* Formats messages according to very simple rules.
* See {@link #format(String, Object)} and
* {@link #format(String, Object, Object)} 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.".
*
* The {} pair is called the formatting element. It serves to designate the
* location where the argument needs to be inserted within the pattern.
*
* @param messagePattern The message pattern which will be parsed and formatted
* @param argument The argument to be inserted instead of the formatting element
* @return The formatted message
*/
public static String format(String messagePattern, Object argument) {
int j = messagePattern.indexOf(DELIM_START);
int len = messagePattern.length();
char escape = 'x';
// if there are no { characters or { is the last character of the messsage
// then we just return messagePattern
if (j == -1 || (j + 1 == len)) {
return messagePattern;
} else {
if (j + 1 == len) {
}
char delimStop = messagePattern.charAt(j + 1);
if (j > 0) {
escape = messagePattern.charAt(j - 1);
}
if ((delimStop != DELIM_STOP) || (escape == '\\')) {
// invalid DELIM_START/DELIM_STOP pair or espace character is
// present
return messagePattern;
} else {
StringBuffer sbuf = new StringBuffer(len + 20);
sbuf.append(messagePattern.substring(0, j));
sbuf.append(argument);
sbuf.append(messagePattern.substring(j + 2));
return sbuf.toString();
}
}
}
/**
* /**
* Performs a two argument substitution for the 'messagePattern' passed as
* parameter.
*
* For example, MessageFormatter.format("Hi {}. My name is {}.",
* "there", "David"); will return the string "Hi there. My name is David.".
*
* The '{}' pair is called a formatting element. It serves to designate the
* location where the arguments need to be inserted within the message pattern.
*
* @param messagePattern The message pattern which will be parsed and formatted
* @param arg1 The first argument to replace the first formatting element
* @param arg2 The second argument to replace the second formatting element
* @return The formatted message
*/
public static String format(String messagePattern, Object arg1, Object arg2) {
int i = 0;
int patternLength = messagePattern.length();
int j = messagePattern.indexOf(DELIM_START);
StringBuffer sbuf = new StringBuffer(patternLength + 50);
for (int L = 0; L < 2; L++) {
j = messagePattern.indexOf(DELIM_START, i);
if (j == -1 || (j + 1 == patternLength)) {
// 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, patternLength));
return sbuf.toString();
}
} else {
char delimStop = messagePattern.charAt(j + 1);
if ((delimStop != DELIM_STOP)) {
// invalid DELIM_START/DELIM_STOP pair
sbuf.append(messagePattern.substring(i, patternLength));
return sbuf.toString();
}
sbuf.append(messagePattern.substring(i, j));
sbuf.append((L == 0) ? arg1 : arg2);
i = j + 2;
}
}
// append the characters following the second {} pair.
sbuf.append(messagePattern.substring(i, patternLength));
return sbuf.toString();
}
}