001    /*
002     * JBoss DNA (http://www.jboss.org/dna)
003     * See the COPYRIGHT.txt file distributed with this work for information
004     * regarding copyright ownership.  Some portions may be licensed
005     * to Red Hat, Inc. under one or more contributor license agreements.
006     * See the AUTHORS.txt file in the distribution for a full listing of 
007     * individual contributors. 
008     *
009     * JBoss DNA is free software. Unless otherwise indicated, all code in JBoss DNA
010     * is licensed to you under the terms of the GNU Lesser General Public License as
011     * published by the Free Software Foundation; either version 2.1 of
012     * the License, or (at your option) any later version.
013     *
014     * JBoss DNA is distributed in the hope that it will be useful,
015     * but WITHOUT ANY WARRANTY; without even the implied warranty of
016     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
017     * Lesser General Public License for more details.
018     *
019     * You should have received a copy of the GNU Lesser General Public
020     * License along with this software; if not, write to the Free
021     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
022     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
023     */
024    package org.jboss.dna.graph.property.basic;
025    
026    import java.text.DecimalFormat;
027    import java.util.ArrayList;
028    import java.util.Collections;
029    import java.util.HashMap;
030    import java.util.HashSet;
031    import java.util.List;
032    import java.util.Map;
033    import java.util.Set;
034    import net.jcip.annotations.NotThreadSafe;
035    import org.jboss.dna.common.util.CheckArg;
036    import org.jboss.dna.graph.property.NamespaceRegistry;
037    
038    /**
039     * A simple {@link NamespaceRegistry} implementation that is not thread-safe, but that provides all the basic functionality.
040     * 
041     * @author Randall Hauch
042     */
043    @NotThreadSafe
044    public class SimpleNamespaceRegistry implements NamespaceRegistry {
045    
046        public static final String DEFAULT_NAMESPACE_URI = "";
047        public static final String DEFAULT_PREFIX_TEMPLATE = "ns##000";
048        public static final String DEFAULT_PREFIX_NUMBER_FORMAT = "##000";
049    
050        private final Map<String, String> namespacesByPrefix = new HashMap<String, String>();
051        private final Map<String, String> prefixesByNamespace = new HashMap<String, String>();
052        private String generatedPrefixTemplate = DEFAULT_PREFIX_TEMPLATE;
053        private int nextGeneratedPrefixNumber = 1;
054    
055        /**
056         * 
057         */
058        public SimpleNamespaceRegistry() {
059            this(DEFAULT_NAMESPACE_URI);
060        }
061    
062        /**
063         * @param defaultNamespaceUri the namespace URI to use for the default prefix
064         */
065        public SimpleNamespaceRegistry( final String defaultNamespaceUri ) {
066            register("", defaultNamespaceUri);
067        }
068    
069        /**
070         * @return prefixTemplate
071         */
072        public String getGeneratedPrefixTemplate() {
073            return this.generatedPrefixTemplate;
074        }
075    
076        /**
077         * @param prefixTemplate Sets prefixTemplate to the specified value.
078         */
079        public void setGeneratedPrefixTemplate( String prefixTemplate ) {
080            if (prefixTemplate == null) prefixTemplate = DEFAULT_PREFIX_TEMPLATE;
081            this.generatedPrefixTemplate = prefixTemplate;
082        }
083    
084        /**
085         * {@inheritDoc}
086         */
087        public String getNamespaceForPrefix( String prefix ) {
088            CheckArg.isNotNull(prefix, "prefix");
089            return this.namespacesByPrefix.get(prefix);
090        }
091    
092        /**
093         * {@inheritDoc}
094         */
095        public String getPrefixForNamespaceUri( String namespaceUri,
096                                                boolean generateIfMissing ) {
097            CheckArg.isNotNull(namespaceUri, "namespaceUri");
098            String prefix = null;
099            prefix = this.prefixesByNamespace.get(namespaceUri);
100            if (prefix == null && generateIfMissing) {
101                // Now we can genereate a prefix and register it ...
102                prefix = this.generatePrefix();
103                this.register(prefix, namespaceUri);
104                return prefix;
105            }
106            return prefix;
107        }
108    
109        /**
110         * {@inheritDoc}
111         */
112        public boolean isRegisteredNamespaceUri( String namespaceUri ) {
113            CheckArg.isNotNull(namespaceUri, "namespaceUri");
114            return this.prefixesByNamespace.containsKey(namespaceUri);
115        }
116    
117        /**
118         * {@inheritDoc}
119         */
120        public String getDefaultNamespaceUri() {
121            return this.namespacesByPrefix.get("");
122        }
123    
124        /**
125         * {@inheritDoc}
126         */
127        public String register( String prefix,
128                                String namespaceUri ) {
129            CheckArg.isNotNull(namespaceUri, "namespaceUri");
130            String previousNamespaceForPrefix = null;
131            namespaceUri = namespaceUri.trim();
132            if (prefix == null) prefix = generatePrefix();
133            prefix = prefix.trim();
134            prefix = prefix.replaceFirst("^:+", "");
135            prefix = prefix.replaceFirst(":+$", "");
136            previousNamespaceForPrefix = this.namespacesByPrefix.put(prefix, namespaceUri);
137            String previousPrefix = this.prefixesByNamespace.put(namespaceUri, prefix);
138            if (previousPrefix != null && !previousPrefix.equals(prefix)) {
139                this.namespacesByPrefix.remove(previousPrefix);
140            }
141            if (previousNamespaceForPrefix != null && !previousNamespaceForPrefix.equals(namespaceUri)) {
142                this.prefixesByNamespace.remove(previousNamespaceForPrefix);
143            }
144            return previousNamespaceForPrefix;
145        }
146    
147        /**
148         * {@inheritDoc}
149         * 
150         * @see org.jboss.dna.graph.property.NamespaceRegistry#unregister(java.lang.String)
151         */
152        public boolean unregister( String namespaceUri ) {
153            CheckArg.isNotNull(namespaceUri, "namespaceUri");
154            namespaceUri = namespaceUri.trim();
155            String prefix = this.prefixesByNamespace.remove(namespaceUri);
156            if (prefix == null) return false;
157            this.namespacesByPrefix.remove(prefix);
158            return true;
159        }
160    
161        /**
162         * {@inheritDoc}
163         */
164        public Set<String> getRegisteredNamespaceUris() {
165            Set<String> result = new HashSet<String>();
166            result.addAll(this.prefixesByNamespace.keySet());
167            return Collections.unmodifiableSet(result);
168        }
169    
170        /**
171         * {@inheritDoc}
172         * 
173         * @see org.jboss.dna.graph.property.NamespaceRegistry#getNamespaces()
174         */
175        public Set<Namespace> getNamespaces() {
176            Set<Namespace> result = new HashSet<Namespace>();
177            for (Map.Entry<String, String> entry : this.namespacesByPrefix.entrySet()) {
178                result.add(new BasicNamespace(entry.getKey(), entry.getValue()));
179            }
180            return Collections.unmodifiableSet(result);
181        }
182    
183        /**
184         * {@inheritDoc}
185         * 
186         * @see java.lang.Object#toString()
187         */
188        @Override
189        public String toString() {
190            List<Namespace> namespaces = new ArrayList<Namespace>(getNamespaces());
191            Collections.sort(namespaces);
192            return namespaces.toString();
193        }
194    
195        protected String generatePrefix() {
196            DecimalFormat formatter = new DecimalFormat(this.generatedPrefixTemplate);
197            return formatter.format(nextGeneratedPrefixNumber++);
198        }
199    
200    }