Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 org.apache.tomcat.util; import java.io.File; import java.io.FilenameFilter; import java.io.IOException; import java.lang.reflect.InvocationTargetException; import java.lang.reflect.Method; import java.net.InetAddress; import java.net.MalformedURLException; import java.net.URL; import java.net.UnknownHostException; import java.util.Hashtable; import java.util.StringTokenizer; import java.util.Vector; // Depends: JDK1.1 /** * Utils for introspection and reflection */ public final class IntrospectionUtils { private static org.apache.commons.logging.Log log = org.apache.commons.logging.LogFactory .getLog(IntrospectionUtils.class); /** * Call execute() - any ant-like task should work */ public static void execute(Object proxy, String method) throws Exception { Method executeM = null; Class c = proxy.getClass(); Class params[] = new Class[0]; // params[0]=args.getClass(); executeM = findMethod(c, method, params); if (executeM == null) { throw new RuntimeException("No execute in " + proxy.getClass()); } executeM.invoke(proxy, (Object[]) null);//new Object[] { args }); } /** * Call void setAttribute( String ,Object ) */ public static void setAttribute(Object proxy, String n, Object v) throws Exception { if (proxy instanceof AttributeHolder) { ((AttributeHolder) proxy).setAttribute(n, v); return; } Method executeM = null; Class c = proxy.getClass(); Class params[] = new Class[2]; params[0] = String.class; params[1] = Object.class; executeM = findMethod(c, "setAttribute", params); if (executeM == null) { if (log.isDebugEnabled()) log.debug("No setAttribute in " + proxy.getClass()); return; } if (false) if (log.isDebugEnabled()) log.debug("Setting " + n + "=" + v + " in " + proxy); executeM.invoke(proxy, new Object[] { n, v }); return; } /** * Call void getAttribute( String ) */ public static Object getAttribute(Object proxy, String n) throws Exception { Method executeM = null; Class c = proxy.getClass(); Class params[] = new Class[1]; params[0] = String.class; executeM = findMethod(c, "getAttribute", params); if (executeM == null) { if (log.isDebugEnabled()) log.debug("No getAttribute in " + proxy.getClass()); return null; } return executeM.invoke(proxy, new Object[] { n }); } /** * Construct a URLClassLoader. Will compile and work in JDK1.1 too. */ public static ClassLoader getURLClassLoader(URL urls[], ClassLoader parent) { try { Class urlCL = Class.forName("java.net.URLClassLoader"); Class paramT[] = new Class[2]; paramT[0] = urls.getClass(); paramT[1] = ClassLoader.class; Method m = findMethod(urlCL, "newInstance", paramT); if (m == null) return null; ClassLoader cl = (ClassLoader) m.invoke(urlCL, new Object[] { urls, parent }); return cl; } catch (ClassNotFoundException ex) { // jdk1.1 return null; } catch (Exception ex) { ex.printStackTrace(); return null; } } public static String guessInstall(String installSysProp, String homeSysProp, String jarName) { return guessInstall(installSysProp, homeSysProp, jarName, null); } /** * Guess a product install/home by analyzing the class path. It works for * product using the pattern: lib/executable.jar or if executable.jar is * included in classpath by a shell script. ( java -jar also works ) * * Insures both "install" and "home" System properties are set. If either or * both System properties are unset, "install" and "home" will be set to the * same value. This value will be the other System property that is set, or * the guessed value if neither is set. */ public static String guessInstall(String installSysProp, String homeSysProp, String jarName, String classFile) { String install = null; String home = null; if (installSysProp != null) install = System.getProperty(installSysProp); if (homeSysProp != null) home = System.getProperty(homeSysProp); if (install != null) { if (home == null) System.getProperties().put(homeSysProp, install); return install; } // Find the directory where jarName.jar is located String cpath = System.getProperty("java.class.path"); String pathSep = System.getProperty("path.separator"); StringTokenizer st = new StringTokenizer(cpath, pathSep); while (st.hasMoreTokens()) { String path = st.nextToken(); // log( "path " + path ); if (path.endsWith(jarName)) { home = path.substring(0, path.length() - jarName.length()); try { if ("".equals(home)) { home = new File("./").getCanonicalPath(); } else if (home.endsWith(File.separator)) { home = home.substring(0, home.length() - 1); } File f = new File(home); String parentDir = f.getParent(); if (parentDir == null) parentDir = home; // unix style File f1 = new File(parentDir); install = f1.getCanonicalPath(); if (installSysProp != null) System.getProperties().put(installSysProp, install); if (home == null && homeSysProp != null) System.getProperties().put(homeSysProp, install); return install; } catch (Exception ex) { ex.printStackTrace(); } } else { String fname = path + (path.endsWith("/") ? "" : "/") + classFile; if (new File(fname).exists()) { try { File f = new File(path); String parentDir = f.getParent(); if (parentDir == null) parentDir = path; // unix style File f1 = new File(parentDir); install = f1.getCanonicalPath(); if (installSysProp != null) System.getProperties().put(installSysProp, install); if (home == null && homeSysProp != null) System.getProperties().put(homeSysProp, install); return install; } catch (Exception ex) { ex.printStackTrace(); } } } } // if install directory can't be found, use home as the default if (home != null) { System.getProperties().put(installSysProp, home); return home; } return null; } /** * Debug method, display the classpath */ public static void displayClassPath(String msg, URL[] cp) { if (log.isDebugEnabled()) { log.debug(msg); for (int i = 0; i < cp.length; i++) { log.debug(cp[i].getFile()); } } } public static String PATH_SEPARATOR = System.getProperty("path.separator"); /** * Adds classpath entries from a vector of URL's to the "tc_path_add" System * property. This System property lists the classpath entries common to web * applications. This System property is currently used by Jasper when its * JSP servlet compiles the Java file for a JSP. */ public static String classPathAdd(URL urls[], String cp) { if (urls == null) return cp; for (int i = 0; i < urls.length; i++) { if (cp != null) cp += PATH_SEPARATOR + urls[i].getFile(); else cp = urls[i].getFile(); } return cp; } /** * Find a method with the right name If found, call the method ( if param is * int or boolean we'll convert value to the right type before) - that means * you can have setDebug(1). */ public static void setProperty(Object o, String name, String value) { if (dbg > 1) d("setProperty(" + o.getClass() + " " + name + "=" + value + ")"); String setter = "set" + capitalize(name); try { Method methods[] = findMethods(o.getClass()); Method setPropertyMethod = null; // First, the ideal case - a setFoo( String ) method for (int i = 0; i < methods.length; i++) { Class paramT[] = methods[i].getParameterTypes(); if (setter.equals(methods[i].getName()) && paramT.length == 1 && "java.lang.String".equals(paramT[0].getName())) { methods[i].invoke(o, new Object[] { value }); return; } } // Try a setFoo ( int ) or ( boolean ) for (int i = 0; i < methods.length; i++) { boolean ok = true; if (setter.equals(methods[i].getName()) && methods[i].getParameterTypes().length == 1) { // match - find the type and invoke it Class paramType = methods[i].getParameterTypes()[0]; Object params[] = new Object[1]; // Try a setFoo ( int ) if ("java.lang.Integer".equals(paramType.getName()) || "int".equals(paramType.getName())) { try { params[0] = new Integer(value); } catch (NumberFormatException ex) { ok = false; } // Try a setFoo ( long ) } else if ("java.lang.Long".equals(paramType.getName()) || "long".equals(paramType.getName())) { try { params[0] = new Long(value); } catch (NumberFormatException ex) { ok = false; } // Try a setFoo ( boolean ) } else if ("java.lang.Boolean".equals(paramType.getName()) || "boolean".equals(paramType.getName())) { params[0] = new Boolean(value); // Try a setFoo ( InetAddress ) } else if ("java.net.InetAddress".equals(paramType.getName())) { try { params[0] = InetAddress.getByName(value); } catch (UnknownHostException exc) { d("Unable to resolve host name:" + value); ok = false; } // Unknown type } else { d("Unknown type " + paramType.getName()); } if (ok) { methods[i].invoke(o, params); return; } } // save "setProperty" for later if ("setProperty".equals(methods[i].getName())) { setPropertyMethod = methods[i]; } } // Ok, no setXXX found, try a setProperty("name", "value") if (setPropertyMethod != null) { Object params[] = new Object[2]; params[0] = name; params[1] = value; setPropertyMethod.invoke(o, params); } } catch (IllegalArgumentException ex2) { log.warn("IAE " + o + " " + name + " " + value, ex2); } catch (SecurityException ex1) { if (dbg > 0) d("SecurityException for " + o.getClass() + " " + name + "=" + value + ")"); if (dbg > 1) ex1.printStackTrace(); } catch (IllegalAccessException iae) { if (dbg > 0) d("IllegalAccessException for " + o.getClass() + " " + name + "=" + value + ")"); if (dbg > 1) iae.printStackTrace(); } catch (InvocationTargetException ie) { if (dbg > 0) d("InvocationTargetException for " + o.getClass() + " " + name + "=" + value + ")"); if (dbg > 1) ie.printStackTrace(); } } public static Object getProperty(Object o, String name) { String getter = "get" + capitalize(name); String isGetter = "is" + capitalize(name); try { Method methods[] = findMethods(o.getClass()); Method getPropertyMethod = null; // First, the ideal case - a getFoo() method for (int i = 0; i < methods.length; i++) { Class paramT[] = methods[i].getParameterTypes(); if (getter.equals(methods[i].getName()) && paramT.length == 0) { return methods[i].invoke(o, (Object[]) null); } if (isGetter.equals(methods[i].getName()) && paramT.length == 0) { return methods[i].invoke(o, (Object[]) null); } if ("getProperty".equals(methods[i].getName())) { getPropertyMethod = methods[i]; } } // Ok, no setXXX found, try a getProperty("name") if (getPropertyMethod != null) { Object params[] = new Object[1]; params[0] = name; return getPropertyMethod.invoke(o, params); } } catch (IllegalArgumentException ex2) { log.warn("IAE " + o + " " + name, ex2); } catch (SecurityException ex1) { if (dbg > 0) d("SecurityException for " + o.getClass() + " " + name + ")"); if (dbg > 1) ex1.printStackTrace(); } catch (IllegalAccessException iae) { if (dbg > 0) d("IllegalAccessException for " + o.getClass() + " " + name + ")"); if (dbg > 1) iae.printStackTrace(); } catch (InvocationTargetException ie) { if (dbg > 0) d("InvocationTargetException for " + o.getClass() + " " + name + ")"); if (dbg > 1) ie.printStackTrace(); } return null; } /** */ public static void setProperty(Object o, String name) { String setter = "set" + capitalize(name); try { Method methods[] = findMethods(o.getClass()); Method setPropertyMethod = null; // find setFoo() method for (int i = 0; i < methods.length; i++) { Class paramT[] = methods[i].getParameterTypes(); if (setter.equals(methods[i].getName()) && paramT.length == 0) { methods[i].invoke(o, new Object[] {}); return; } } } catch (Exception ex1) { if (dbg > 0) d("Exception for " + o.getClass() + " " + name); if (dbg > 1) ex1.printStackTrace(); } } /** * Replace ${NAME} with the property value * * @deprecated Use the explicit method */ public static String replaceProperties(String value, Object getter) { if (getter instanceof Hashtable) return replaceProperties(value, (Hashtable) getter, null); if (getter instanceof PropertySource) { PropertySource src[] = new PropertySource[] { (PropertySource) getter }; return replaceProperties(value, null, src); } return value; } /** * Replace ${NAME} with the property value */ public static String replaceProperties(String value, Hashtable staticProp, PropertySource dynamicProp[]) { StringBuffer sb = new StringBuffer(); int prev = 0; // assert value!=nil int pos; while ((pos = value.indexOf("$", prev)) >= 0) { if (pos > 0) { sb.append(value.substring(prev, pos)); } if (pos == (value.length() - 1)) { sb.append('$'); prev = pos + 1; } else if (value.charAt(pos + 1) != '{') { sb.append('$'); prev = pos + 1; // XXX } else { int endName = value.indexOf('}', pos); if (endName < 0) { sb.append(value.substring(pos)); prev = value.length(); continue; } String n = value.substring(pos + 2, endName); String v = null; if (staticProp != null) { v = (String) ((Hashtable) staticProp).get(n); } if (v == null && dynamicProp != null) { for (int i = 0; i < dynamicProp.length; i++) { v = dynamicProp[i].getProperty(n); if (v != null) { break; } } } if (v == null) v = "${" + n + "}"; sb.append(v); prev = endName + 1; } } if (prev < value.length()) sb.append(value.substring(prev)); return sb.toString(); } /** * Reverse of Introspector.decapitalize */ public static String capitalize(String name) { if (name == null || name.length() == 0) { return name; } char chars[] = name.toCharArray(); chars[0] = Character.toUpperCase(chars[0]); return new String(chars); } public static String unCapitalize(String name) { if (name == null || name.length() == 0) { return name; } char chars[] = name.toCharArray(); chars[0] = Character.toLowerCase(chars[0]); return new String(chars); } // -------------------- Class path tools -------------------- /** * Add all the jar files in a dir to the classpath, represented as a Vector * of URLs. */ public static void addToClassPath(Vector cpV, String dir) { try { String cpComp[] = getFilesByExt(dir, ".jar"); if (cpComp != null) { int jarCount = cpComp.length; for (int i = 0; i < jarCount; i++) { URL url = getURL(dir, cpComp[i]); if (url != null) cpV.addElement(url); } } } catch (Exception ex) { ex.printStackTrace(); } } public static void addToolsJar(Vector v) { try { // Add tools.jar in any case File f = new File(System.getProperty("java.home") + "/../lib/tools.jar"); if (!f.exists()) { // On some systems java.home gets set to the root of jdk. // That's a bug, but we can work around and be nice. f = new File(System.getProperty("java.home") + "/lib/tools.jar"); if (f.exists()) { if (log.isDebugEnabled()) log.debug("Detected strange java.home value " + System.getProperty("java.home") + ", it should point to jre"); } } URL url = new URL("file", "", f.getAbsolutePath()); v.addElement(url); } catch (MalformedURLException ex) { ex.printStackTrace(); } } /** * Return all files with a given extension in a dir */ public static String[] getFilesByExt(String ld, String ext) { File dir = new File(ld); String[] names = null; final String lext = ext; if (dir.isDirectory()) { names = dir.list(new FilenameFilter() { public boolean accept(File d, String name) { if (name.endsWith(lext)) { return true; } return false; } }); } return names; } /** * Construct a file url from a file, using a base dir */ public static URL getURL(String base, String file) { try { File baseF = new File(base); File f = new File(baseF, file); String path = f.getCanonicalPath(); if (f.isDirectory()) { path += "/"; } if (!f.exists()) return null; return new URL("file", "", path); } catch (Exception ex) { ex.printStackTrace(); return null; } } /** * Add elements from the classpath <i>cp </i> to a Vector <i>jars </i> as * file URLs (We use Vector for JDK 1.1 compat). * <p> * * @param jars The jar list * @param cp a String classpath of directory or jar file elements * separated by path.separator delimiters. * @throws IOException If an I/O error occurs * @throws MalformedURLException Doh ;) */ public static void addJarsFromClassPath(Vector jars, String cp) throws IOException, MalformedURLException { String sep = System.getProperty("path.separator"); String token; StringTokenizer st; if (cp != null) { st = new StringTokenizer(cp, sep); while (st.hasMoreTokens()) { File f = new File(st.nextToken()); String path = f.getCanonicalPath(); if (f.isDirectory()) { path += "/"; } URL url = new URL("file", "", path); if (!jars.contains(url)) { jars.addElement(url); } } } } /** * Return a URL[] that can be used to construct a class loader */ public static URL[] getClassPath(Vector v) { URL[] urls = new URL[v.size()]; for (int i = 0; i < v.size(); i++) { urls[i] = (URL) v.elementAt(i); } return urls; } /** * Construct a URL classpath from files in a directory, a cpath property, * and tools.jar. */ public static URL[] getClassPath(String dir, String cpath, String cpathProp, boolean addTools) throws IOException, MalformedURLException { Vector jarsV = new Vector(); if (dir != null) { // Add dir/classes first, if it exists URL url = getURL(dir, "classes"); if (url != null) jarsV.addElement(url); addToClassPath(jarsV, dir); } if (cpath != null) addJarsFromClassPath(jarsV, cpath); if (cpathProp != null) { String cpath1 = System.getProperty(cpathProp); addJarsFromClassPath(jarsV, cpath1); } if (addTools) addToolsJar(jarsV); return getClassPath(jarsV); } // -------------------- Mapping command line params to setters public static boolean processArgs(Object proxy, String args[]) throws Exception { String args0[] = null; if (null != findMethod(proxy.getClass(), "getOptions1", new Class[] {})) { args0 = (String[]) callMethod0(proxy, "getOptions1"); } if (args0 == null) { //args0=findVoidSetters(proxy.getClass()); args0 = findBooleanSetters(proxy.getClass()); } Hashtable h = null; if (null != findMethod(proxy.getClass(), "getOptionAliases", new Class[] {})) { h = (Hashtable) callMethod0(proxy, "getOptionAliases"); } return processArgs(proxy, args, args0, null, h); } public static boolean processArgs(Object proxy, String args[], String args0[], String args1[], Hashtable aliases) throws Exception { for (int i = 0; i < args.length; i++) { String arg = args[i]; if (arg.startsWith("-")) arg = arg.substring(1); if (aliases != null && aliases.get(arg) != null) arg = (String) aliases.get(arg); if (args0 != null) { boolean set = false; for (int j = 0; j < args0.length; j++) { if (args0[j].equalsIgnoreCase(arg)) { setProperty(proxy, args0[j], "true"); set = true; break; } } if (set) continue; } if (args1 != null) { for (int j = 0; j < args1.length; j++) { if (args1[j].equalsIgnoreCase(arg)) { i++; if (i >= args.length) return false; setProperty(proxy, arg, args[i]); break; } } } else { // if args1 is not specified,assume all other options have param i++; if (i >= args.length) return false; setProperty(proxy, arg, args[i]); } } return true; } // -------------------- other utils -------------------- public static void clear() { objectMethods.clear(); } public static String[] findVoidSetters(Class c) { Method m[] = findMethods(c); if (m == null) return null; Vector v = new Vector(); for (int i = 0; i < m.length; i++) { if (m[i].getName().startsWith("set") && m[i].getParameterTypes().length == 0) { String arg = m[i].getName().substring(3); v.addElement(unCapitalize(arg)); } } String s[] = new String[v.size()]; for (int i = 0; i < s.length; i++) { s[i] = (String) v.elementAt(i); } return s; } public static String[] findBooleanSetters(Class c) { Method m[] = findMethods(c); if (m == null) return null; Vector v = new Vector(); for (int i = 0; i < m.length; i++) { if (m[i].getName().startsWith("set") && m[i].getParameterTypes().length == 1 && "boolean".equalsIgnoreCase(m[i].getParameterTypes()[0].getName())) { String arg = m[i].getName().substring(3); v.addElement(unCapitalize(arg)); } } String s[] = new String[v.size()]; for (int i = 0; i < s.length; i++) { s[i] = (String) v.elementAt(i); } return s; } static Hashtable objectMethods = new Hashtable(); public static Method[] findMethods(Class c) { Method methods[] = (Method[]) objectMethods.get(c); if (methods != null) return methods; methods = c.getMethods(); objectMethods.put(c, methods); return methods; } public static Method findMethod(Class c, String name, Class params[]) { Method methods[] = findMethods(c); if (methods == null) return null; for (int i = 0; i < methods.length; i++) { if (methods[i].getName().equals(name)) { Class methodParams[] = methods[i].getParameterTypes(); if (methodParams == null) if (params == null || params.length == 0) return methods[i]; if (params == null) if (methodParams == null || methodParams.length == 0) return methods[i]; if (params.length != methodParams.length) continue; boolean found = true; for (int j = 0; j < params.length; j++) { if (params[j] != methodParams[j]) { found = false; break; } } if (found) return methods[i]; } } return null; } /** Test if the object implements a particular * method */ public static boolean hasHook(Object obj, String methodN) { try { Method myMethods[] = findMethods(obj.getClass()); for (int i = 0; i < myMethods.length; i++) { if (methodN.equals(myMethods[i].getName())) { // check if it's overriden Class declaring = myMethods[i].getDeclaringClass(); Class parentOfDeclaring = declaring.getSuperclass(); // this works only if the base class doesn't extend // another class. // if the method is declared in a top level class // like BaseInterceptor parent is Object, otherwise // parent is BaseInterceptor or an intermediate class if (!"java.lang.Object".equals(parentOfDeclaring.getName())) { return true; } } } } catch (Exception ex) { ex.printStackTrace(); } return false; } public static void callMain(Class c, String args[]) throws Exception { Class p[] = new Class[1]; p[0] = args.getClass(); Method m = c.getMethod("main", p); m.invoke(c, new Object[] { args }); } public static Object callMethod1(Object target, String methodN, Object param1, String typeParam1, ClassLoader cl) throws Exception { if (target == null || param1 == null) { d("Assert: Illegal params " + target + " " + param1); } if (dbg > 0) d("callMethod1 " + target.getClass().getName() + " " + param1.getClass().getName() + " " + typeParam1); Class params[] = new Class[1]; if (typeParam1 == null) params[0] = param1.getClass(); else params[0] = cl.loadClass(typeParam1); Method m = findMethod(target.getClass(), methodN, params); if (m == null) throw new NoSuchMethodException(target.getClass().getName() + " " + methodN); return m.invoke(target, new Object[] { param1 }); } public static Object callMethod0(Object target, String methodN) throws Exception { if (target == null) { d("Assert: Illegal params " + target); return null; } if (dbg > 0) d("callMethod0 " + target.getClass().getName() + "." + methodN); Class params[] = new Class[0]; Method m = findMethod(target.getClass(), methodN, params); if (m == null) throw new NoSuchMethodException(target.getClass().getName() + " " + methodN); return m.invoke(target, emptyArray); } static Object[] emptyArray = new Object[] {}; public static Object callMethodN(Object target, String methodN, Object params[], Class typeParams[]) throws Exception { Method m = null; m = findMethod(target.getClass(), methodN, typeParams); if (m == null) { d("Can't find method " + methodN + " in " + target + " CLASS " + target.getClass()); return null; } Object o = m.invoke(target, params); if (dbg > 0) { // debug StringBuffer sb = new StringBuffer(); sb.append("" + target.getClass().getName() + "." + methodN + "( "); for (int i = 0; i < params.length; i++) { if (i > 0) sb.append(", "); sb.append(params[i]); } sb.append(")"); d(sb.toString()); } return o; } public static Object convert(String object, Class paramType) { Object result = null; if ("java.lang.String".equals(paramType.getName())) { result = object; } else if ("java.lang.Integer".equals(paramType.getName()) || "int".equals(paramType.getName())) { try { result = new Integer(object); } catch (NumberFormatException ex) { } // Try a setFoo ( boolean ) } else if ("java.lang.Boolean".equals(paramType.getName()) || "boolean".equals(paramType.getName())) { result = new Boolean(object); // Try a setFoo ( InetAddress ) } else if ("java.net.InetAddress".equals(paramType.getName())) { try { result = InetAddress.getByName(object); } catch (UnknownHostException exc) { d("Unable to resolve host name:" + object); } // Unknown type } else { d("Unknown type " + paramType.getName()); } if (result == null) { throw new IllegalArgumentException("Can't convert argument: " + object); } return result; } // -------------------- Get property -------------------- // This provides a layer of abstraction public static interface PropertySource { public String getProperty(String key); } public static interface AttributeHolder { public void setAttribute(String key, Object o); } // debug -------------------- static final int dbg = 0; static void d(String s) { if (log.isDebugEnabled()) log.debug("IntrospectionUtils: " + s); } }