Java tutorial
/* * $Header: /home/cvs/jakarta-tomcat-connectors/util/java/org/apache/tomcat/util/compat/JdkCompat.java,v 1.10 2003/08/14 06:36:02 billbarker Exp $ * $Revision: 1.10 $ * $Date: 2003/08/14 06:36:02 $ * ==================================================================== * * The Apache Software License, Version 1.1 * * Copyright (c) 1999 The Apache Software Foundation. All rights * reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * 2. 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. * * 3. The end-user documentation included with the redistribution, if * any, must include the following acknowlegement: * "This product includes software developed by the * Apache Software Foundation (http://www.apache.org/)." * Alternately, this acknowlegement may appear in the software itself, * if and wherever such third-party acknowlegements normally appear. * * 4. The names "The Jakarta Project", "Tomcat", and "Apache Software * Foundation" must not be used to endorse or promote products derived * from this software without prior written permission. For written * permission, please contact apache@apache.org. * * 5. Products derived from this software may not be called "Apache" * nor may "Apache" appear in their names without prior written * permission of the Apache Group. * * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR * ITS 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. * ==================================================================== * * This software consists of voluntary contributions made by many * individuals on behalf of the Apache Software Foundation. For more * information on the Apache Software Foundation, please see * <http://www.apache.org/>. * * [Additional notices, if required by prior licensing conditions] * */ package org.apache.tomcat.util.compat; import java.io.File; import java.io.IOException; import java.net.URL; import java.net.MalformedURLException; import java.util.Vector; import java.io.PrintWriter; import java.io.StringWriter; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; /** * General-purpose utility to provide backward-compatibility and JDK * independence. This allow use of JDK1.3 ( or higher ) facilities if * available, while maintaining the code compatible with older VMs. * * The goal is to make backward-compatiblity reasonably easy. * * The base class supports JDK1.3 behavior. * * @author Tim Funk */ public class JdkCompat { // ------------------------------------------------------- Static Variables /** * class providing java2 support */ static final String JAVA14_SUPPORT = "org.apache.tomcat.util.compat.Jdk14Compat"; /** * Commons logger wrapper */ static Log logger = LogFactory.getLog(JdkCompat.class); /** Return java version as a string */ public static String getJavaVersion() { return javaVersion; } public static boolean isJava2() { return java2; } public static boolean isJava14() { return java14; } // -------------------- Implementation -------------------- // from ant public static final String JAVA_1_0 = "1.0"; public static final String JAVA_1_1 = "1.1"; public static final String JAVA_1_2 = "1.2"; public static final String JAVA_1_3 = "1.3"; public static final String JAVA_1_4 = "1.4"; static String javaVersion; static boolean java2 = false; static boolean java14 = false; static JdkCompat jdkCompat; static { init(); } private static void init() { try { javaVersion = JAVA_1_0; Class.forName("java.lang.Void"); javaVersion = JAVA_1_1; Class.forName("java.lang.ThreadLocal"); java2 = true; javaVersion = JAVA_1_2; Class.forName("java.lang.StrictMath"); javaVersion = JAVA_1_3; Class.forName("java.lang.CharSequence"); javaVersion = JAVA_1_4; java14 = true; } catch (ClassNotFoundException cnfe) { // swallow as we've hit the max class version that we have } if (java14) { try { Class c = Class.forName(JAVA14_SUPPORT); jdkCompat = (JdkCompat) c.newInstance(); } catch (Exception ex) { jdkCompat = new JdkCompat(); } } else { jdkCompat = new JdkCompat(); // Install jar handler if none installed } } // ----------------------------------------------------------- Constructors /** * Default no-arg constructor */ protected JdkCompat() { } // --------------------------------------------------------- Public Methods /** * Get a compatibiliy helper class. */ public static JdkCompat getJdkCompat() { return jdkCompat; } /** * Return the URI for the given file. Originally created for * o.a.c.loader.WebappClassLoader * * @param File to wrap into URI * @return A URI as a URL */ public URL getURI(File file) throws MalformedURLException { File realFile = file; try { realFile = realFile.getCanonicalFile(); } catch (IOException e) { // Ignore } return realFile.toURL(); } /** * Return the maximum amount of memory the JVM will attempt to use. */ public long getMaxMemory() { return (-1L); } /** * Print out a partial servlet stack trace (truncating at the last * occurrence of javax.servlet.). */ public String getPartialServletStackTrace(Throwable t) { StringWriter stackTrace = new StringWriter(); t.printStackTrace(new PrintWriter(stackTrace)); String st = stackTrace.toString(); int i = st.lastIndexOf("org.apache.catalina.core.ApplicationFilterChain.internalDoFilter"); if (i > -1) { return st.substring(0, i - 4); } else { return st; } } /** * Splits a string into it's components. * @param path String to split * @param pat Pattern to split at * @return the components of the path */ public String[] split(String path, String pat) { Vector comps = new Vector(); int pos = path.indexOf(pat); int start = 0; while (pos >= 0) { if (pos > start) { String comp = path.substring(start, pos); comps.add(comp); } start = pos + pat.length(); pos = path.indexOf(pat, start); } if (start < path.length()) { comps.add(path.substring(start)); } String[] result = new String[comps.size()]; for (int i = 0; i < comps.size(); i++) { result[i] = (String) comps.elementAt(i); } return result; } }