Back to index...

	/*
	* Copyright (c) 1999, 2011, 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 = 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 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<RefAddr> mycomps = getAll();
	Enumeration<RefAddr> 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<RefAddr> 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;
	};

Back to index...