Tomcat example source code file (DirContextURLStreamHandler.java)

This example Tomcat source code file (DirContextURLStreamHandler.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

classloader, classloader, dircontext, dircontext, dircontexturlconnection, dircontexturlstreamhandler, dircontexturlstreamhandler, hashtable, hashtable, illegalstateexception, io, ioexception, net, network, string, stringbuffer, urlconnection, util

The Tomcat DirContextURLStreamHandler.java source code

/*
 * 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.naming.resources;

import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.util.Hashtable;

import javax.naming.directory.DirContext;

/**
 * Stream handler to a JNDI directory context.
 * 
 * @author <a href="mailto:remm@apache.org">Remy Maucherat
 * @version $Revision: 467222 $
 */
public class DirContextURLStreamHandler 
    extends URLStreamHandler {
    
    
    // ----------------------------------------------------------- Constructors
    
    
    public DirContextURLStreamHandler() {
    }
    
    
    public DirContextURLStreamHandler(DirContext context) {
        this.context = context;
    }
    
    
    // -------------------------------------------------------------- Variables
    
    
    /**
     * Bindings class loader - directory context. Keyed by CL id.
     */
    private static Hashtable clBindings = new Hashtable();
    
    
    /**
     * Bindings thread - directory context. Keyed by thread id.
     */
    private static Hashtable threadBindings = new Hashtable();
    
    
    // ----------------------------------------------------- Instance Variables
    
    
    /**
     * Directory context.
     */
    protected DirContext context = null;
    
    
    // ------------------------------------------------------------- Properties
    
    
    // ----------------------------------------------- URLStreamHandler Methods
    
    
    /**
     * Opens a connection to the object referenced by the <code>URL 
     * argument.
     */
    protected URLConnection openConnection(URL u) 
        throws IOException {
        DirContext currentContext = this.context;
        if (currentContext == null)
            currentContext = get();
        return new DirContextURLConnection(currentContext, u);
    }
    
    
    // ------------------------------------------------------------ URL Methods
    
    
    /**
     * Override as part of the fix for 36534, to ensure toString is correct.
     */
    protected String toExternalForm(URL u) {
        // pre-compute length of StringBuffer
        int len = u.getProtocol().length() + 1;
        if (u.getPath() != null) {
            len += u.getPath().length();
        }
        if (u.getQuery() != null) {
            len += 1 + u.getQuery().length();
        }
        if (u.getRef() != null) 
            len += 1 + u.getRef().length();
        StringBuffer result = new StringBuffer(len);
        result.append(u.getProtocol());
        result.append(":");
        if (u.getPath() != null) {
            result.append(u.getPath());
        }
        if (u.getQuery() != null) {
            result.append('?');
            result.append(u.getQuery());
        }
        if (u.getRef() != null) {
            result.append("#");
            result.append(u.getRef());
        }
        return result.toString();
    }


    // --------------------------------------------------------- Public Methods
    
    
    /**
     * Set the java.protocol.handler.pkgs system property.
     */
    public static void setProtocolHandler() {
        String value = System.getProperty(Constants.PROTOCOL_HANDLER_VARIABLE);
        if (value == null) {
            value = Constants.Package;
            System.setProperty(Constants.PROTOCOL_HANDLER_VARIABLE, value);
        } else if (value.indexOf(Constants.Package) == -1) {
            value += "|" + Constants.Package;
            System.setProperty(Constants.PROTOCOL_HANDLER_VARIABLE, value);
        }
    }
    
    
    /**
     * Returns true if the thread or the context class loader of the current 
     * thread is bound.
     */
    public static boolean isBound() {
        return (clBindings.containsKey
                (Thread.currentThread().getContextClassLoader()))
            || (threadBindings.containsKey(Thread.currentThread()));
    }
    
    
    /**
     * Binds a directory context to a class loader.
     */
    public static void bind(DirContext dirContext) {
        ClassLoader currentCL = 
            Thread.currentThread().getContextClassLoader();
        if (currentCL != null)
            clBindings.put(currentCL, dirContext);
    }
    
    
    /**
     * Unbinds a directory context to a class loader.
     */
    public static void unbind() {
        ClassLoader currentCL = 
            Thread.currentThread().getContextClassLoader();
        if (currentCL != null)
            clBindings.remove(currentCL);
    }
    
    
    /**
     * Binds a directory context to a thread.
     */
    public static void bindThread(DirContext dirContext) {
        threadBindings.put(Thread.currentThread(), dirContext);
    }
    
    
    /**
     * Unbinds a directory context to a thread.
     */
    public static void unbindThread() {
        threadBindings.remove(Thread.currentThread());
    }
    
    
    /**
     * Get the bound context.
     */
    public static DirContext get() {

        DirContext result = null;

        Thread currentThread = Thread.currentThread();
        ClassLoader currentCL = currentThread.getContextClassLoader();

        // Checking CL binding
        result = (DirContext) clBindings.get(currentCL);
        if (result != null)
            return result;

        // Checking thread biding
        result = (DirContext) threadBindings.get(currentThread);

        // Checking parent CL binding
        currentCL = currentCL.getParent();
        while (currentCL != null) {
            result = (DirContext) clBindings.get(currentCL);
            if (result != null)
                return result;
            currentCL = currentCL.getParent();
        }

        if (result == null)
            throw new IllegalStateException("Illegal class loader binding");

        return result;

    }
    
    
    /**
     * Binds a directory context to a class loader.
     */
    public static void bind(ClassLoader cl, DirContext dirContext) {
        clBindings.put(cl, dirContext);
    }
    
    
    /**
     * Unbinds a directory context to a class loader.
     */
    public static void unbind(ClassLoader cl) {
        clBindings.remove(cl);
    }
    
    
    /**
     * Get the bound context.
     */
    public static DirContext get(ClassLoader cl) {
        return (DirContext) clBindings.get(cl);
    }
    
    
    /**
     * Get the bound context.
     */
    public static DirContext get(Thread thread) {
        return (DirContext) threadBindings.get(thread);
    }
    
    
}