Java tutorial
/* * JBoss, Home of Professional Open Source * Copyright 2005, JBoss Inc., and individual contributors as indicated * by the @authors tag. See the copyright.txt in the distribution for a * full listing of individual contributors. * * This is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as * published by the Free Software Foundation; either version 2.1 of * the License, or (at your option) any later version. * * This software 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 * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this software; if not, write to the Free * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA * 02110-1301 USA, or see the FSF site: http://www.fsf.org. */ import javax.naming.Context; import javax.naming.InitialContext; import javax.naming.LinkRef; import javax.naming.Name; import javax.naming.NameNotFoundException; import javax.naming.NamingException; /** * A static utility class for common JNDI operations. * * @author Scott.Stark@jboss.org * @author adrian@jboss.com * @version $Revision: 2787 $ */ @SuppressWarnings("unchecked") public class Util { /** * Create a subcontext including any intermediate contexts. * * @param ctx * the parent JNDI Context under which value will be bound * @param name * the name relative to ctx of the subcontext. * @return The new or existing JNDI subcontext * @throws javax.naming.NamingException * on any JNDI failure */ public static Context createSubcontext(Context ctx, String name) throws NamingException { Name n = ctx.getNameParser("").parse(name); return createSubcontext(ctx, n); } /** * Create a subcontext including any intermediate contexts. * * @param ctx * the parent JNDI Context under which value will be bound * @param name * the name relative to ctx of the subcontext. * @return The new or existing JNDI subcontext * @throws NamingException * on any JNDI failure */ public static Context createSubcontext(Context ctx, Name name) throws NamingException { Context subctx = ctx; for (int pos = 0; pos < name.size(); pos++) { String ctxName = name.get(pos); try { subctx = (Context) ctx.lookup(ctxName); } catch (NameNotFoundException e) { subctx = ctx.createSubcontext(ctxName); } // The current subctx will be the ctx for the next name component ctx = subctx; } return subctx; } /** * Bind val to name in ctx, and make sure that all intermediate contexts exist * * @param ctx * the parent JNDI Context under which value will be bound * @param name * the name relative to ctx where value will be bound * @param value * the value to bind. * @throws NamingException * for any error */ public static void bind(Context ctx, String name, Object value) throws NamingException { Name n = ctx.getNameParser("").parse(name); bind(ctx, n, value); } /** * Bind val to name in ctx, and make sure that all intermediate contexts exist * * @param ctx * the parent JNDI Context under which value will be bound * @param name * the name relative to ctx where value will be bound * @param value * the value to bind. * @throws NamingException * for any error */ public static void bind(Context ctx, Name name, Object value) throws NamingException { int size = name.size(); String atom = name.get(size - 1); Context parentCtx = createSubcontext(ctx, name.getPrefix(size - 1)); parentCtx.bind(atom, value); } /** * Rebind val to name in ctx, and make sure that all intermediate contexts * exist * * @param ctx * the parent JNDI Context under which value will be bound * @param name * the name relative to ctx where value will be bound * @param value * the value to bind. * @throws NamingException * for any error */ public static void rebind(Context ctx, String name, Object value) throws NamingException { Name n = ctx.getNameParser("").parse(name); rebind(ctx, n, value); } /** * Rebind val to name in ctx, and make sure that all intermediate contexts * exist * * @param ctx * the parent JNDI Context under which value will be bound * @param name * the name relative to ctx where value will be bound * @param value * the value to bind. * @throws NamingException * for any error */ public static void rebind(Context ctx, Name name, Object value) throws NamingException { int size = name.size(); String atom = name.get(size - 1); Context parentCtx = createSubcontext(ctx, name.getPrefix(size - 1)); parentCtx.rebind(atom, value); } /** * Unbinds a name from ctx, and removes parents if they are empty * * @param ctx * the parent JNDI Context under which the name will be unbound * @param name * The name to unbind * @throws NamingException * for any error */ public static void unbind(Context ctx, String name) throws NamingException { unbind(ctx, ctx.getNameParser("").parse(name)); } /** * Unbinds a name from ctx, and removes parents if they are empty * * @param ctx * the parent JNDI Context under which the name will be unbound * @param name * The name to unbind * @throws NamingException * for any error */ public static void unbind(Context ctx, Name name) throws NamingException { ctx.unbind(name); // unbind the end node in the name int sz = name.size(); // walk the tree backwards, stopping at the domain while (--sz > 0) { Name pname = name.getPrefix(sz); try { ctx.destroySubcontext(pname); } catch (NamingException e) { System.out.println("Unable to remove context " + pname + e); break; } } } /** * Lookup an object in the default initial context * * @param name * the name to lookup * @param clazz * the expected type * @return the object * @throws Exception * for any error */ public static Object lookup(String name, Class<?> clazz) throws Exception { InitialContext ctx = new InitialContext(); try { return lookup(ctx, name, clazz); } finally { ctx.close(); } } /** * Lookup an object in the default initial context * * @param name * the name to lookup * @param clazz * the expected type * @return the object * @throws Exception * for any error */ public static Object lookup(Name name, Class<?> clazz) throws Exception { InitialContext ctx = new InitialContext(); try { return lookup(ctx, name, clazz); } finally { ctx.close(); } } /** * Lookup an object in the given context * * @param context * the context * @param name * the name to lookup * @param clazz * the expected type * @return the object * @throws Exception * for any error */ public static Object lookup(Context context, String name, Class clazz) throws Exception { Object result = context.lookup(name); checkObject(context, name, result, clazz); return result; } /** * Lookup an object in the given context * * @param context * the context * @param name * the name to lookup * @param clazz * the expected type * @return the object * @throws Exception * for any error */ public static Object lookup(Context context, Name name, Class clazz) throws Exception { Object result = context.lookup(name); checkObject(context, name.toString(), result, clazz); return result; } /** * Create a link * * @param fromName * the from name * @param toName * the to name * @throws NamingException * for any error */ public static void createLinkRef(String fromName, String toName) throws NamingException { InitialContext ctx = new InitialContext(); createLinkRef(ctx, fromName, toName); } /** * Create a link * * @param ctx * the context * @param fromName * the from name * @param toName * the to name * @throws NamingException * for any error */ public static void createLinkRef(Context ctx, String fromName, String toName) throws NamingException { LinkRef link = new LinkRef(toName); Context fromCtx = ctx; Name name = ctx.getNameParser("").parse(fromName); String atom = name.get(name.size() - 1); for (int n = 0; n < name.size() - 1; n++) { String comp = name.get(n); try { fromCtx = (Context) fromCtx.lookup(comp); } catch (NameNotFoundException e) { fromCtx = fromCtx.createSubcontext(comp); } } System.out.println("atom: " + atom); System.out.println("link: " + link); fromCtx.rebind(atom, link); System.out.println("Bound link " + fromName + " to " + toName); } /** * Remove the link ref * * @param name * the name of the link binding * @throws NamingException * for any error */ public static void removeLinkRef(String name) throws NamingException { InitialContext ctx = new InitialContext(); removeLinkRef(ctx, name); } /** * Remove the link ref * * @param ctx * the context * @param name * the name of the link binding * @throws NamingException * for any error */ public static void removeLinkRef(Context ctx, String name) throws NamingException { System.out.println("Unbinding link " + name); ctx.unbind(name); } /** * Checks an object implements the given class * * @param context * the context * @param name * the name to lookup * @param object * the object * @param clazz * the expected type * @throws Exception * for any error */ protected static void checkObject(Context context, String name, Object object, Class clazz) throws Exception { Class objectClass = object.getClass(); if (clazz.isAssignableFrom(objectClass) == false) { StringBuffer buffer = new StringBuffer(100); buffer.append("Object at '").append(name); buffer.append("' in context ").append(context.getEnvironment()); buffer.append(" is not an instance of "); appendClassInfo(buffer, clazz); buffer.append(" object class is "); appendClassInfo(buffer, object.getClass()); throw new ClassCastException(buffer.toString()); } } /** * Append Class Info * * @param buffer * the buffer to append to * @param clazz * the class to describe */ protected static void appendClassInfo(StringBuffer buffer, Class clazz) { buffer.append("[class=").append(clazz.getName()); buffer.append(" classloader=").append(clazz.getClassLoader()); buffer.append(" interfaces={"); Class[] interfaces = clazz.getInterfaces(); for (int i = 0; i < interfaces.length; ++i) { if (i > 0) buffer.append(", "); buffer.append("interface=").append(interfaces[i].getName()); buffer.append(" classloader=").append(interfaces[i].getClassLoader()); } buffer.append("}]"); } }