/* * Copyright (c) 1999, 2004, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation.  Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code 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 General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package javax.naming; import java.util.Vector;import java.util.Enumeration; /**  * This class represents a reference to an object that is found outside of  * the naming/directory system.  *<p>  * Reference provides a way of recording address information about  * objects which themselves are not directly bound to the naming/directory system.  *<p>  * A Reference consists of an ordered list of addresses and class information  * about the object being referenced.  * Each address in the list identifies a communications endpoint  * for the same conceptual object.  The "communications endpoint"  * is information that indicates how to contact the object. It could  * be, for example, a network address, a location in memory on the  * local machine, another process on the same machine, etc.  * The order of the addresses in the list may be of significance  * to object factories that interpret the reference.  *<p>  * Multiple addresses may arise for  * various reasons, such as replication or the object offering interfaces  * over more than one communication mechanism.  The addresses are indexed  * starting with zero.  *<p>  * A Reference also contains information to assist in creating an instance  * of the object to which this Reference refers.  It contains the class name  * of that object, and the class name and location of the factory to be used  * to create the object.  * The class factory location is a space-separated list of URLs representing  * the class path used to load the factory.  When the factory class (or  * any class or resource upon which it depends) needs to be loaded,  * each URL is used (in order) to attempt to load the class.  *<p>  * A Reference instance is not synchronized against concurrent access by multiple  * threads. Threads that need to access a single Reference concurrently should  * synchronize amongst themselves and provide the necessary locking.  *  * @author Rosanna Lee  * @author Scott Seligman  *  * @see RefAddr  * @see StringRefAddr  * @see BinaryRefAddr  * @since 1.3  */   /*<p>  * The serialized form of a Reference object consists of the class  * name of the object being referenced (a String), a Vector of the  * addresses (each a RefAddr), the name of the class factory (a  * String), and the location of the class factory (a String).*/  public class Reference implements Cloneable, java.io.Serializable {    /**     * Contains the fully-qualified name of the class of the object to which     * this Reference refers.     * @serial     * @see java.lang.Class#getName     */    protected String className;    /**     * Contains the addresses contained in this Reference.     * Initialized by constructor.     * @serial     */    protected Vector<RefAddr> addrs = null;     /**     * Contains the name of the factory class for creating     * an instance of the object to which this Reference refers.     * Initialized to null.     * @serial     */    protected String classFactory = null;     /**     * Contains the location of the factory class.     * Initialized to null.     * @serial     */    protected String classFactoryLocation = null;     /**      * Constructs a new reference for an object with class name 'className'.      * Class factory and class factory location are set to null.      * The newly created reference contains zero addresses.      *      * @param className The non-null class name of the object to which      * this reference refers.      */    public Reference(String className) {        this.className  = className;        addrs = new Vector();    }     /**      * Constructs a new reference for an object with class name 'className' and      * an address.      * Class factory and class factory location are set to null.      *      * @param className The non-null class name of the object to      * which this reference refers.      * @param addr The non-null address of the object.      */    public Reference(String className, RefAddr addr) {        this.className = className;        addrs = new Vector();        addrs.addElement(addr);    }     /**      * Constructs a new reference for an object with class name 'className',      * and the class name and location of the object's factory.      *      * @param className The non-null class name of the object to which      *                         this reference refers.      * @param factory  The possibly null class name of the object's factory.      * @param factoryLocation      *         The possibly null location from which to load      *         the factory (e.g. URL)      * @see javax.naming.spi.ObjectFactory      * @see javax.naming.spi.NamingManager#getObjectInstance      */    public Reference(String className, String factory, String factoryLocation) {        this(className);        classFactory = factory;        classFactoryLocation = factoryLocation;    }     /**      * Constructs a new reference for an object with class name 'className',      * the class name and location of the object's factory, and the address for      * the object.      *      * @param className The non-null class name of the object to      *         which this reference refers.      * @param factory  The possibly null class name of the object's factory.      * @param factoryLocation  The possibly null location from which      *                         to load the factory (e.g. URL)      * @param addr     The non-null address of the object.      * @see javax.naming.spi.ObjectFactory      * @see javax.naming.spi.NamingManager#getObjectInstance      */    public Reference(String className, RefAddr addr,                     String factory, String factoryLocation) {        this(className, addr);        classFactory = factory;        classFactoryLocation = factoryLocation;    }     /**      * Retrieves the class name of the object to which this reference refers.      *      * @return The non-null fully-qualified class name of the object.      *         (e.g. "java.lang.String")      */    public String getClassName() {        return className;    }     /**      * Retrieves the class name of the factory of the object      * to which this reference refers.      *      * @return The possibly null fully-qualified class name of the factory.      *         (e.g. "java.lang.String")      */    public String getFactoryClassName() {        return classFactory;    }     /**      * Retrieves the location of the factory of the object      * to which this reference refers.      * If it is a codebase, then it is an ordered list of URLs,      * separated by spaces, listing locations from where the factory      * class definition should be loaded.      *      * @return The possibly null string containing the      *                 location for loading in the factory's class.      */    public String getFactoryClassLocation() {        return classFactoryLocation;    }     /**      * Retrieves the first address that has the address type 'addrType'.      * String.compareTo() is used to test the equality of the address types.      *      * @param addrType The non-null address type for which to find the address.      * @return The address in this reference with address type 'addrType;      *         null if no such address exist.      */    public RefAddr get(String addrType) {        int len = addrs.size();        RefAddr addr;        for (int i = 0; i < len; i++) {            addr = (RefAddr) addrs.elementAt(i);            if (addr.getType().compareTo(addrType) == 0)                return addr;        }        return null;    }     /**      * Retrieves the address at index posn.      * @param posn The index of the address to retrieve.      * @return The address at the 0-based index posn. It must be in the      *         range [0,getAddressCount()).      * @exception ArrayIndexOutOfBoundsException If posn not in the specified      *         range.      */    public RefAddr get(int posn) {        return ((RefAddr) addrs.elementAt(posn));    }     /**      * Retrieves an enumeration of the addresses in this reference.      * When addresses are added, changed or removed from this reference,      * its effects on this enumeration are undefined.      *      * @return An non-null enumeration of the addresses      *         (<tt>RefAddr</tt>) in this reference.      *         If this reference has zero addresses, an enumeration with      *         zero elements is returned.      */    public Enumeration<RefAddr> getAll() {        return addrs.elements();    }     /**      * Retrieves the number of addresses in this reference.      *      * @return The nonnegative number of addresses in this reference.      */    public int size() {        return addrs.size();    }     /**      * Adds an address to the end of the list of addresses.      *      * @param addr The non-null address to add.      */    public void add(RefAddr addr) {        addrs.addElement(addr);    }     /**      * Adds an address to the list of addresses at index posn.      * All addresses at index posn or greater are shifted up      * the list by one (away from index 0).      *      * @param posn The 0-based index of the list to insert addr.      * @param addr The non-null address to add.      * @exception ArrayIndexOutOfBoundsException If posn not in the specified      *         range.      */    public void add(int posn, RefAddr addr) {        addrs.insertElementAt(addr, posn);    }     /**      * Deletes the address at index posn from the list of addresses.      * All addresses at index greater than posn are shifted down      * the list by one (towards index 0).      *      * @param posn The 0-based index of in address to delete.      * @return The address removed.      * @exception ArrayIndexOutOfBoundsException If posn not in the specified      *         range.      */    public Object remove(int posn) {        Object r = addrs.elementAt(posn);        addrs.removeElementAt(posn);        return r;    }     /**      * Deletes all addresses from this reference.      */    public void clear() {        addrs.setSize(0);    }     /**      * Determines whether obj is a reference with the same addresses      * (in same order) as this reference.      * The addresses are checked using RefAddr.equals().      * In addition to having the same addresses, the Reference also needs to      * have the same class name as this reference.      * The class factory and class factory location are not checked.      * If obj is null or not an instance of Reference, null is returned.      *      * @param obj The possibly null object to check.      * @return true if obj is equal to this reference; false otherwise.      */    public boolean equals(Object obj) {        if ((obj != null) && (obj instanceof Reference)) {            Reference target = (Reference)obj;            // ignore factory information            if (target.className.equals(this.className) &&                target.size() ==  this.size()) {                Enumeration mycomps = getAll();                Enumeration comps = target.getAll();                while (mycomps.hasMoreElements())                    if (!(mycomps.nextElement().equals(comps.nextElement())))                        return false;                return true;            }        }        return false;    }     /**      * Computes the hash code of this reference.      * The hash code is the sum of the hash code of its addresses.      *      * @return A hash code of this reference as an int.      */    public int hashCode() {        int hash = className.hashCode();        for (Enumeration e = getAll(); e.hasMoreElements();)            hash += e.nextElement().hashCode();        return hash;    }     /**      * Generates the string representation of this reference.      * The string consists of the class name to which this reference refers,      * and the string representation of each of its addresses.      * This representation is intended for display only and not to be parsed.      *      * @return The non-null string representation of this reference.      */    public String toString() {        StringBuffer buf = new StringBuffer("Reference Class Name: " +                                            className + "\n");        int len = addrs.size();        for (int i = 0; i < len; i++)            buf.append(get(i).toString());         return buf.toString();    }     /**     * Makes a copy of this reference using its class name     * list of addresses, class factory name and class factory location.     * Changes to the newly created copy does not affect this Reference     * and vice versa.     */    public Object clone() {        Reference r = new Reference(className, classFactory, classFactoryLocation);        Enumeration<RefAddr> a = getAll();        r.addrs = new Vector();         while (a.hasMoreElements())            r.addrs.addElement(a.nextElement());        return r;    }    /**     * Use serialVersionUID from JNDI 1.1.1 for interoperability     */    private static final long serialVersionUID = -1673475790065791735L;};