001    package biweekly.io.xml;
002    
003    import java.util.Arrays;
004    import java.util.Iterator;
005    
006    import javax.xml.namespace.NamespaceContext;
007    import javax.xml.xpath.XPath;
008    
009    /*
010     Copyright (c) 2013, Michael Angstadt
011     All rights reserved.
012    
013     Redistribution and use in source and binary forms, with or without
014     modification, are permitted provided that the following conditions are met: 
015    
016     1. Redistributions of source code must retain the above copyright notice, this
017     list of conditions and the following disclaimer. 
018     2. Redistributions in binary form must reproduce the above copyright notice,
019     this list of conditions and the following disclaimer in the documentation
020     and/or other materials provided with the distribution. 
021    
022     THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
023     ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
024     WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
025     DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
026     ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
027     (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
028     LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
029     ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
030     (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
031     SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
032     */
033    
034    /**
035     * Used for xCal xpath expressions.
036     * @see XPath#setNamespaceContext(NamespaceContext)
037     * @author Michael Angstadt
038     */
039    public class XCalNamespaceContext implements NamespaceContext {
040            /**
041             * The XML namespace for xCal documents.
042             */
043            public static final String XCAL_NS = "urn:ietf:params:xml:ns:icalendar-2.0";
044    
045            private final String prefix;
046    
047            /**
048             * Creates a new namespace context.
049             * @param prefix the prefix to use in xpath expressions
050             */
051            public XCalNamespaceContext(String prefix) {
052                    this.prefix = prefix;
053            }
054    
055            /**
056             * Gets the prefix to use in xpath expressions.
057             * @return the xpath prefix
058             */
059            public String getPrefix() {
060                    return prefix;
061            }
062    
063            //@Override
064            public String getNamespaceURI(String prefix) {
065                    if (this.prefix.equals(prefix)) {
066                            return XCAL_NS;
067                    }
068                    return null;
069            }
070    
071            //@Override
072            public String getPrefix(String ns) {
073                    if (XCAL_NS.equals(ns)) {
074                            return prefix;
075                    }
076                    return null;
077            }
078    
079            //@Override
080            public Iterator<String> getPrefixes(String ns) {
081                    if (XCAL_NS.equals(ns)) {
082                            return Arrays.asList(prefix).iterator();
083                    }
084                    return null;
085            }
086    }