/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* 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 com.badlogic.gdx.utils;
import java.util.Locale;
/** {@code TextFormatter} is used by {@link I18NBundle} to perform argument replacement.
* <p>
* This class partially emulates its counterpart in the core package. See {@link #format(String, Object...)}
*
* @author davebaol */
public class TextFormatter {
private StringBuilder buffer = new StringBuilder();
public TextFormatter (Locale locale, boolean useMessageFormat) {
// both arguments are meaningless for GWT
}
/** Formats the given {@code pattern} replacing any placeholder of the form {0}, {1}, {2} and so on with the corresponding
* object from {@code args} converted to a string with {@code toString()}, so without taking into account the locale.
* <p>
* This method only implements a small subset of the grammar supported by {@link java.text.MessageFormat}. Especially,
* placeholder are only made up of an index; neither the type nor the style are supported.
* <p>
* If nothing has been replaced this implementation returns the pattern itself.
*
* @param pattern the pattern
* @param args the arguments
* @return the formatted pattern
* @exception IllegalArgumentException if the pattern is invalid */
public String format (String pattern, Object... args) {
buffer.setLength(0);
boolean changed = false;
int placeholder = -1;
int patternLength = pattern.length();
for (int i = 0; i < patternLength; ++i) {
char ch = pattern.charAt(i);
if (placeholder < 0) { // processing constant part
if (ch == '{') {
changed = true;
if (i + 1 < patternLength && pattern.charAt(i + 1) == '{') {
buffer.append(ch); // handle escaped '{'
++i;
} else {
placeholder = 0; // switch to placeholder part
}
} else {
buffer.append(ch);
}
} else { // processing placeholder part
if (ch == '}') {
if (placeholder >= args.length)
throw new IllegalArgumentException("Argument index out of bounds: " + placeholder);
if (pattern.charAt(i - 1) == '{')
throw new IllegalArgumentException("Missing argument index after a left curly brace");
if (args[placeholder] == null)
buffer.append("null"); // append null argument
else
buffer.append(args[placeholder].toString()); // append actual argument
placeholder = -1; // switch to constant part
} else {
if (ch < '0' || ch > '9')
throw new IllegalArgumentException("Unexpected '" + ch + "' while parsing argument index");
placeholder = placeholder * 10 + (ch - '0');
}
}
}
if (placeholder >= 0) throw new IllegalArgumentException("Unmatched braces in the pattern.");
return changed ? buffer.toString() : pattern;
}
}