001 /* 002 * JBoss, Home of Professional Open Source. 003 * Copyright 2008, Red Hat Middleware LLC, and individual contributors 004 * as indicated by the @author tags. See the copyright.txt file in the 005 * distribution for a full listing of individual contributors. 006 * 007 * This is free software; you can redistribute it and/or modify it 008 * under the terms of the GNU Lesser General Public License as 009 * published by the Free Software Foundation; either version 2.1 of 010 * the License, or (at your option) any later version. 011 * 012 * This software is distributed in the hope that it will be useful, 013 * but WITHOUT ANY WARRANTY; without even the implied warranty of 014 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 015 * Lesser General Public License for more details. 016 * 017 * You should have received a copy of the GNU Lesser General Public 018 * License along with this software; if not, write to the Free 019 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 020 * 02110-1301 USA, or see the FSF site: http://www.fsf.org. 021 */ 022 package org.jboss.dna.graph.properties; 023 024 import java.util.Set; 025 import net.jcip.annotations.Immutable; 026 import net.jcip.annotations.ThreadSafe; 027 028 /** 029 * Registry of namespaces, which are used to provide isolated and independent domains for {@link Name names}. 030 * 031 * @author Randall Hauch 032 */ 033 @ThreadSafe 034 public interface NamespaceRegistry { 035 036 /** 037 * Return the namespace URI that is currently mapped to the empty prefix, or null if there is no current default namespace. 038 * 039 * @return the namespace URI that represents the default namespace, or null if there is no default namespace 040 */ 041 String getDefaultNamespaceUri(); 042 043 /** 044 * Get the namespace URI for the supplied prefix. 045 * 046 * @param prefix the namespace prefix 047 * @return the namespace URI for the supplied prefix, or null if there is no namespace currently registered to use that prefix 048 * @throws IllegalArgumentException if the prefix is null 049 */ 050 String getNamespaceForPrefix( String prefix ); 051 052 /** 053 * Return the prefix used for the supplied namespace URI. 054 * 055 * @param namespaceUri the namespace URI 056 * @param generateIfMissing true if the namespace URI has not already been registered and the method should auto-register the 057 * namespace with a generated prefix, or false if the method should never auto-register the namespace 058 * @return the prefix currently being used for the namespace, or <code>null</code> if the namespace has not been registered 059 * and <code>generateIfMissing</code> is <code>false</code> 060 * @throws IllegalArgumentException if the namespace URI is null 061 * @see #isRegisteredNamespaceUri(String) 062 */ 063 String getPrefixForNamespaceUri( String namespaceUri, 064 boolean generateIfMissing ); 065 066 /** 067 * Return whether there is a registered prefix for the supplied namespace URI. 068 * 069 * @param namespaceUri the namespace URI 070 * @return true if the supplied namespace has been registered with a prefix, or false otherwise 071 * @throws IllegalArgumentException if the namespace URI is null 072 */ 073 boolean isRegisteredNamespaceUri( String namespaceUri ); 074 075 /** 076 * Register a new namespace using the supplied prefix, returning the namespace URI previously registered under that prefix. 077 * 078 * @param prefix the prefix for the namespace, or null if a namesapce prefix should be generated automatically 079 * @param namespaceUri the namespace URI 080 * @return the namespace URI that was previously registered with the supplied prefix, or null if the prefix was not previously 081 * bound to a namespace URI 082 * @throws IllegalArgumentException if the namespace URI is null 083 */ 084 String register( String prefix, 085 String namespaceUri ); 086 087 /** 088 * Unregister the namespace with the supplied URI. 089 * 090 * @param namespaceUri the namespace URI 091 * @return true if the namespace was removed, or false if the namespace was not registered 092 * @throws IllegalArgumentException if the namespace URI is null 093 * @throws NamespaceException if there is a problem unregistering the namespace 094 */ 095 boolean unregister( String namespaceUri ); 096 097 /** 098 * Obtain the set of namespaces that are registered. 099 * 100 * @return the set of 101 */ 102 Set<String> getRegisteredNamespaceUris(); 103 104 /** 105 * Obtain a snapshot of all of the {@link Namespace namespaces} registered at the time this method is called. The resulting 106 * set is immutable, and will <i>not</i> reflect changes made to the registry. 107 * 108 * @return an immutable set of {@link Namespace} objects reflecting a snapshot of the registry; never null 109 */ 110 Set<Namespace> getNamespaces(); 111 112 /** 113 * Representation of a single namespace at a single point in time. This object does not change to reflect changes made to the 114 * {@link NamespaceRegistry registry}. 115 * 116 * @see NamespaceRegistry#getNamespaces() 117 * @author Randall Hauch 118 */ 119 @Immutable 120 interface Namespace { 121 /** 122 * Get the prefix for the namespace 123 * 124 * @return the prefix; never null but possibly the empty string 125 */ 126 String getPrefix(); 127 128 /** 129 * Get the URI for the namespace 130 * 131 * @return the namespace URI; never null but possibly the empty string 132 */ 133 String getNamespaceUri(); 134 } 135 136 }