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* Copyright (c) 2000, 2006, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package java.util.logging;
/**
* A Formatter provides support for formatting LogRecords.
* <p>
* Typically each logging Handler will have a Formatter associated
* with it. The Formatter takes a LogRecord and converts it to
* a string.
* <p>
* Some formatters (such as the XMLFormatter) need to wrap head
* and tail strings around a set of formatted records. The getHeader
* and getTail methods can be used to obtain these strings.
*
* @since 1.4
*/
public abstract class Formatter {
/**
* Construct a new formatter.
*/
protected Formatter() {
}
/**
* Format the given log record and return the formatted string.
* <p>
* The resulting formatted String will normally include a
* localized and formated version of the LogRecord's message field.
* It is recommended to use the {@link Formatter#formatMessage}
* convenience method to localize and format the message field.
*
* @param record the log record to be formatted.
* @return the formatted log record
*/
public abstract String format(LogRecord record);
/**
* Return the header string for a set of formatted records.
* <p>
* This base class returns an empty string, but this may be
* overriden by subclasses.
*
* @param h The target handler (can be null)
* @return header string
*/
public String getHead(Handler h) {
return "";
}
/**
* Return the tail string for a set of formatted records.
* <p>
* This base class returns an empty string, but this may be
* overriden by subclasses.
*
* @param h The target handler (can be null)
* @return tail string
*/
public String getTail(Handler h) {
return "";
}
/**
* Localize and format the message string from a log record. This
* method is provided as a convenience for Formatter subclasses to
* use when they are performing formatting.
* <p>
* The message string is first localized to a format string using
* the record's ResourceBundle. (If there is no ResourceBundle,
* or if the message key is not found, then the key is used as the
* format string.) The format String uses java.text style
* formatting.
* <ul>
* <li>If there are no parameters, no formatter is used.
* <li>Otherwise, if the string contains "{0" then
* java.text.MessageFormat is used to format the string.
* <li>Otherwise no formatting is performed.
* </ul>
* <p>
*
* @param record the log record containing the raw message
* @return a localized and formatted message
*/
public synchronized String formatMessage(LogRecord record) {
String format = record.getMessage();
java.util.ResourceBundle catalog = record.getResourceBundle();
if (catalog != null) {
try {
format = catalog.getString(record.getMessage());
} catch (java.util.MissingResourceException ex) {
// Drop through. Use record message as format
format = record.getMessage();
}
}
// Do the formatting.
try {
Object parameters[] = record.getParameters();
if (parameters == null || parameters.length == 0) {
// No parameters. Just return format string.
return format;
}
// Is it a java.text style format?
// Ideally we could match with
// Pattern.compile("\\{\\d").matcher(format).find())
// However the cost is 14% higher, so we cheaply check for
// 1 of the first 4 parameters
if (format.indexOf("{0") >= 0 || format.indexOf("{1") >=0 ||
format.indexOf("{2") >=0|| format.indexOf("{3") >=0) {
return java.text.MessageFormat.format(format, parameters);
}
return format;
} catch (Exception ex) {
// Formatting failed: use localized format string.
return format;
}
}
}