Java tutorial
/* * ============================================================================= * Simplified BSD License, see http://www.opensource.org/licenses/ * ----------------------------------------------------------------------------- * Copyright (c) 2008-2009, Marco Terzer, Zurich, Switzerland * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the Swiss Federal Institute of Technology Zurich * nor the names of its contributors may be used to endorse or promote * products derived from this software without specific prior written * permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ============================================================================= */ package ch.javasoft.xml.config; import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.PrintStream; import java.lang.reflect.Constructor; import java.net.URL; import java.util.logging.Level; import java.util.logging.Logger; import org.dom4j.Element; /** * Parses stream elements (or other enclosing elements with a type attribute) * of the following types: * <pre> <stream type="console"> <console type="err"/> </stream> <stream type="console"> <console type="out"/> </stream> <stream type="file"> <file name="{work-dir}/{-log[2]}"/> </stream> <stream type="logger"> <logger name="" level="INFO"/> </stream> * </pre> */ public class StreamConfigParser { private static final String LOG_PRINT_STREAM_CLASSNAME = "ch.javasoft.util.logging.LogPrintStream"; public static enum XmlElement implements XmlNode { stream, console, file, url, logger; public String getXmlName() { return name(); } } public static enum XmlAttribute implements XmlNode { name, type, value, level; public String getXmlName() { return name(); } } public static enum XmlOutputStreamType { file, console, logger; public String xmlName() { return name(); } public static XmlOutputStreamType find(String typeAttributeValue) { for (XmlOutputStreamType type : values()) { if (type.xmlName().equals(typeAttributeValue)) return type; } return null; } } public static enum XmlInputStreamType { file, url; public String xmlName() { return name(); } public static XmlInputStreamType find(String typeAttributeValue) { for (XmlInputStreamType type : values()) { if (type.xmlName().equals(typeAttributeValue)) return type; } return null; } } public static enum ConsoleType { out, err; public static ConsoleType find(String typeAttributeValue) { for (ConsoleType type : ConsoleType.values()) { if (type.name().equalsIgnoreCase(typeAttributeValue)) return type; } return null; } public PrintStream getStream() { return this == err ? System.err : System.out; } } /** * Parses an output stream of any type, see class comments * (stream element can be named differently). */ public static OutputStream parseOutputStream(Element streamElement) throws XmlConfigException { String typeName = streamElement.attributeValue(XmlAttribute.type.getXmlName()); XmlOutputStreamType type = XmlOutputStreamType.find(typeName); if (type == null) { throw new XmlConfigException("unknown stream type '" + typeName + "'", streamElement); } switch (type) { case file: return parseFileOutputStream(streamElement); case console: return parseConsolePrintStream(streamElement); case logger: return parseLoggerStream(streamElement); default: //should not happen throw new XmlConfigException("internal error, unknown stream type " + type, streamElement); } } /** * Parses (stream element can be named differently): * <pre> <stream type="file"> <file name="{work-dir}/{-out[2]}"/> </stream> * </pre> */ public static FileOutputStream parseFileOutputStream(Element streamElement) throws XmlConfigException { Element elFile = XmlUtil.getRequiredSingleChildElement(streamElement, XmlElement.file); File file = FileConfigParser.parseFile(elFile); try { return new FileOutputStream(file); } catch (IOException ex) { throw new XmlConfigException("cannot open file output stream for file '" + file.getAbsolutePath() + "'", streamElement, ex); } } /** * Parses (stream element can be named differently): * <pre> <stream type="console"> <console type="out"/> </stream> * </pre> */ public static PrintStream parseConsolePrintStream(Element streamElement) throws XmlConfigException { Element elConsole = XmlUtil.getRequiredSingleChildElement(streamElement, XmlElement.console); String consoleName = elConsole.attributeValue(XmlAttribute.type.getXmlName()); ConsoleType type = ConsoleType.find(consoleName); if (type == null) { throw new XmlConfigException("Unknown console type '" + consoleName + "' for " + XmlElement.console.getXmlName() + " element", streamElement); } return type.getStream(); } /** * Parses (stream element can be named differently): * <pre> <stream type="logger"> <logger name="" level="INFO"/> </stream> * </pre> */ public static PrintStream parseLoggerStream(Element streamElement) throws XmlConfigException { Element elLogLevel = XmlUtil.getRequiredSingleChildElement(streamElement, XmlElement.logger); String loggerName = elLogLevel.attributeValue(XmlAttribute.name.getXmlName()); String levelName = elLogLevel.attributeValue(XmlAttribute.level.getXmlName()); Level logLevel; try { logLevel = Level.parse(levelName); } catch (Exception ex) { throw new XmlConfigException("invalid log level: " + levelName, elLogLevel); } Logger logger = Logger.getLogger(loggerName == null ? "" : loggerName); try { Class<?> streamClass = Class.forName(LOG_PRINT_STREAM_CLASSNAME); Constructor cons = streamClass.getConstructor(new Class[] { Logger.class, Level.class }); return (PrintStream) cons.newInstance(new Object[] { logger, logLevel }); } catch (Exception ex) { throw new XmlConfigException("cannot instantiate log print stream, e=" + ex, elLogLevel); } } /** * Parses (stream element can be named differently): * <pre> <stream type="file"> <file name="{work-dir}/{-out[2]}"/> </stream> <stream type="url"> <url name="http://..."/> </stream> <input type="file"> <file name="{work-dir}/{-out[2]}"/> </input> * </pre> */ public static InputStream parseInputStream(Element streamElement) throws XmlConfigException { String typeName = streamElement.attributeValue(XmlAttribute.type.getXmlName()); XmlInputStreamType type = XmlInputStreamType.find(typeName); if (type == null) { throw new XmlConfigException("unknown stream type '" + typeName + "'", streamElement); } switch (type) { case file: return parseFileInputStream(streamElement); case url: return parseURLInputStream(streamElement); default: //should not happen throw new XmlConfigException("internal error, unknown stream type " + type, streamElement); } } /** * Parses (stream element can be named differently): * <pre> <stream type="file"> <file name="{work-dir}/{-out[2]}"/> </stream> * </pre> */ public static FileInputStream parseFileInputStream(Element streamElement) throws XmlConfigException { Element elFile = XmlUtil.getRequiredSingleChildElement(streamElement, XmlElement.file); File file = FileConfigParser.parseFile(elFile); try { return new FileInputStream(file); } catch (IOException ex) { throw new XmlConfigException("cannot open file input stream for file '" + file.getAbsolutePath() + "'", streamElement, ex); } } /** * Parses (stream element can be named differently): * <pre> <stream type="url"> <url name="{work-dir}/{-out[2]}"/> </stream> * </pre> */ public static InputStream parseURLInputStream(Element streamElement) throws XmlConfigException { Element elURL = XmlUtil.getRequiredSingleChildElement(streamElement, XmlElement.url); URL url = URLConfigParser.parseURL(elURL); try { return url.openStream(); } catch (IOException ex) { throw new XmlConfigException("cannot open URL input stream url '" + url.toExternalForm() + "', e=" + ex, streamElement, ex); } } // no instances private StreamConfigParser() { } }