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	/*
	* Copyright (c) 2000, 2015, 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
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/


	package java.util.logging;

	import java.nio.charset.Charset;
	import java.time.Instant;
	import java.time.format.DateTimeFormatter;
	import java.util.*;

	/**
	* Format a LogRecord into a standard XML format.
	* <p>
	* The DTD specification is provided as Appendix A to the
	* Java Logging APIs specification.
	* <p>
	* The XMLFormatter can be used with arbitrary character encodings,
	* but it is recommended that it normally be used with UTF-8. The
	* character encoding can be set on the output Handler.
	*
	* @implSpec Since JDK 9, instances of {@linkplain LogRecord} contain
	* an {@link LogRecord#getInstant() Instant} which can have nanoseconds below
	* the millisecond resolution.
	* The DTD specification has been updated to allow for an optional
	* {@code <nanos>} element. By default, the XMLFormatter will compute the
	* nanosecond adjustment below the millisecond resolution (using
	* {@code LogRecord.getInstant().getNano() % 1000_000}) - and if this is not 0,
	* this adjustment value will be printed in the new {@code <nanos>} element.
	* The event instant can then be reconstructed using
	* {@code Instant.ofEpochSecond(millis/1000L, (millis % 1000L) * 1000_000L + nanos)}
	* where {@code millis} and {@code nanos} represent the numbers serialized in
	* the {@code <millis>} and {@code <nanos>} elements, respectively.
	* <br>
	* The {@code <date>} element will now contain the whole instant as formatted
	* by the {@link DateTimeFormatter#ISO_INSTANT DateTimeFormatter.ISO_INSTANT}
	* formatter.
	* <p>
	* For compatibility with old parsers, XMLFormatters can
	* be configured to revert to the old format by specifying a
	* {@code <xml-formatter-fully-qualified-class-name>.useInstant = false}
	* {@linkplain LogManager#getProperty(java.lang.String) property} in the
	* logging configuration. When {@code useInstant} is {@code false}, the old
	* formatting will be preserved. When {@code useInstant} is {@code true}
	* (the default), the {@code <nanos>} element will be printed and the
	* {@code <date>} element will contain the {@linkplain
	* DateTimeFormatter#ISO_INSTANT formatted} instant.
	* <p>
	* For instance, in order to configure plain instances of XMLFormatter to omit
	* the new {@code <nano>} element,
	* {@code java.util.logging.XMLFormatter.useInstant = false} can be specified
	* in the logging configuration.
	*
	* @since 1.4
	*/

	public class XMLFormatter extends Formatter {
	private final LogManager manager = LogManager.getLogManager();
	private final boolean useInstant;

	/**
	* Creates a new instance of XMLFormatter.
	*
	* @implSpec
	* Since JDK 9, the XMLFormatter will print out the record {@linkplain
	* LogRecord#getInstant() event time} as an Instant. This instant
	* has the best resolution available on the system. The {@code <date>}
	* element will contain the instant as formatted by the {@link
	* DateTimeFormatter#ISO_INSTANT}.
	* In addition, an optional {@code <nanos>} element containing a
	* nanosecond adjustment will be printed if the instant contains some
	* nanoseconds below the millisecond resolution.
	* <p>
	* This new behavior can be turned off, and the old formatting restored,
	* by specifying a property in the {@linkplain
	* LogManager#getProperty(java.lang.String) logging configuration}.
	* If {@code LogManager.getLogManager().getProperty(
	* this.getClass().getName()+".useInstant")} is {@code "false"} or
	* {@code "0"}, the old formatting will be restored.
	*/
	public XMLFormatter() {
	useInstant = (manager == null)
	\|\| manager.getBooleanProperty(
	this.getClass().getName()+".useInstant", true);
	}

	// Append a two digit number.
	private void a2(StringBuilder sb, int x) {
	if (x < 10) {
	sb.append('0');
	}
	sb.append(x);
	}

	// Append the time and date in ISO 8601 format
	private void appendISO8601(StringBuilder sb, long millis) {
	GregorianCalendar cal = new GregorianCalendar();
	cal.setTimeInMillis(millis);
	sb.append(cal.get(Calendar.YEAR));
	sb.append('-');
	a2(sb, cal.get(Calendar.MONTH) + 1);
	sb.append('-');
	a2(sb, cal.get(Calendar.DAY_OF_MONTH));
	sb.append('T');
	a2(sb, cal.get(Calendar.HOUR_OF_DAY));
	sb.append(':');
	a2(sb, cal.get(Calendar.MINUTE));
	sb.append(':');
	a2(sb, cal.get(Calendar.SECOND));
	}

	// Append to the given StringBuilder an escaped version of the
	// given text string where XML special characters have been escaped.
	// For a null string we append "<null>"
	private void escape(StringBuilder sb, String text) {
	if (text == null) {
	text = "<null>";
	}
	for (int i = 0; i < text.length(); i++) {
	char ch = text.charAt(i);
	if (ch == '<') {
	sb.append("<");
	} else if (ch == '>') {
	sb.append(">");
	} else if (ch == '&') {
	sb.append("&");
	} else {
	sb.append(ch);
	}
	}
	}

	/**
	* Format the given message to XML.
	* <p>
	* This method can be overridden in a subclass.
	* 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 a formatted log record
	*/
	@Override
	public String format(LogRecord record) {
	StringBuilder sb = new StringBuilder(500);
	sb.append("<record>\n");

	final Instant instant = record.getInstant();

	sb.append(" <date>");
	if (useInstant) {
	// If useInstant is true - we will print the instant in the
	// date field, using the ISO_INSTANT formatter.
	DateTimeFormatter.ISO_INSTANT.formatTo(instant, sb);
	} else {
	// If useInstant is false - we will keep the 'old' formating
	appendISO8601(sb, instant.toEpochMilli());
	}
	sb.append("</date>\n");

	sb.append(" <millis>");
	sb.append(instant.toEpochMilli());
	sb.append("</millis>\n");

	final int nanoAdjustment = instant.getNano() % 1000_000;
	if (useInstant && nanoAdjustment != 0) {
	sb.append(" <nanos>");
	sb.append(nanoAdjustment);
	sb.append("</nanos>\n");
	}

	sb.append(" <sequence>");
	sb.append(record.getSequenceNumber());
	sb.append("</sequence>\n");

	String name = record.getLoggerName();
	if (name != null) {
	sb.append(" <logger>");
	escape(sb, name);
	sb.append("</logger>\n");
	}

	sb.append(" <level>");
	escape(sb, record.getLevel().toString());
	sb.append("</level>\n");

	if (record.getSourceClassName() != null) {
	sb.append(" <class>");
	escape(sb, record.getSourceClassName());
	sb.append("</class>\n");
	}

	if (record.getSourceMethodName() != null) {
	sb.append(" <method>");
	escape(sb, record.getSourceMethodName());
	sb.append("</method>\n");
	}

	sb.append(" <thread>");
	sb.append(record.getThreadID());
	sb.append("</thread>\n");

	if (record.getMessage() != null) {
	// Format the message string and its accompanying parameters.
	String message = formatMessage(record);
	sb.append(" <message>");
	escape(sb, message);
	sb.append("</message>");
	sb.append("\n");
	}

	// If the message is being localized, output the key, resource
	// bundle name, and params.
	ResourceBundle bundle = record.getResourceBundle();
	try {
	if (bundle != null && bundle.getString(record.getMessage()) != null) {
	sb.append(" <key>");
	escape(sb, record.getMessage());
	sb.append("</key>\n");
	sb.append(" <catalog>");
	escape(sb, record.getResourceBundleName());
	sb.append("</catalog>\n");
	}
	} catch (Exception ex) {
	// The message is not in the catalog. Drop through.
	}

	Object parameters[] = record.getParameters();
	// Check to see if the parameter was not a messagetext format
	// or was not null or empty
	if (parameters != null && parameters.length != 0
	&& record.getMessage().indexOf('{') == -1 ) {
	for (Object parameter : parameters) {
	sb.append(" <param>");
	try {
	escape(sb, parameter.toString());
	} catch (Exception ex) {
	sb.append("???");
	}
	sb.append("</param>\n");
	}
	}

	if (record.getThrown() != null) {
	// Report on the state of the throwable.
	Throwable th = record.getThrown();
	sb.append(" <exception>\n");
	sb.append(" <message>");
	escape(sb, th.toString());
	sb.append("</message>\n");
	StackTraceElement trace[] = th.getStackTrace();
	for (StackTraceElement frame : trace) {
	sb.append(" <frame>\n");
	sb.append(" <class>");
	escape(sb, frame.getClassName());
	sb.append("</class>\n");
	sb.append(" <method>");
	escape(sb, frame.getMethodName());
	sb.append("</method>\n");
	// Check for a line number.
	if (frame.getLineNumber() >= 0) {
	sb.append(" <line>");
	sb.append(frame.getLineNumber());
	sb.append("</line>\n");
	}
	sb.append(" </frame>\n");
	}
	sb.append(" </exception>\n");
	}

	sb.append("</record>\n");
	return sb.toString();
	}

	/**
	* Return the header string for a set of XML formatted records.
	*
	* @param h The target handler (can be null)
	* @return a valid XML string
	*/
	@Override
	public String getHead(Handler h) {
	StringBuilder sb = new StringBuilder();
	String encoding;
	sb.append("<?xml version=\"1.0\"");

	if (h != null) {
	encoding = h.getEncoding();
	} else {
	encoding = null;
	}

	if (encoding == null) {
	// Figure out the default encoding.
	encoding = java.nio.charset.Charset.defaultCharset().name();
	}
	// Try to map the encoding name to a canonical name.
	try {
	Charset cs = Charset.forName(encoding);
	encoding = cs.name();
	} catch (Exception ex) {
	// We hit problems finding a canonical name.
	// Just use the raw encoding name.
	}

	sb.append(" encoding=\"");
	sb.append(encoding);
	sb.append("\"");
	sb.append(" standalone=\"no\"?>\n");

	sb.append("<!DOCTYPE log SYSTEM \"logger.dtd\">\n");
	sb.append("<log>\n");
	return sb.toString();
	}

	/**
	* Return the tail string for a set of XML formatted records.
	*
	* @param h The target handler (can be null)
	* @return a valid XML string
	*/
	@Override
	public String getTail(Handler h) {
	return "</log>\n";
	}
	}

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