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16 package javax.xml.namespace;
17
18 import java.io.IOException;
19 import java.io.ObjectInputStream;
20 import java.io.Serializable;
21
22 /**
23 * <code>QName</code> class represents the value of a qualified name
24 * as specified in <a href="http://www.w3.org/TR/xmlschema-2/#QName">XML
25 * Schema Part2: Datatypes specification</a>.
26 * <p>
27 * The value of a QName contains a <b>namespaceURI</b>, a <b>localPart</b> and a
28 * <b>prefix</b>. The localPart provides the local part of the qualified name.
29 * The namespaceURI is a URI reference identifying the namespace.
30 *
31 * @version 1.1
32 */
33 public class QName implements Serializable {
34
35 /** Comment/shared empty <code>String</code>. */
36 private static final String emptyString = "".intern();
37
38 private String namespaceURI;
39
40 private String localPart;
41
42 private String prefix;
43
44 /**
45 * Constructor for the QName.
46 *
47 * @param localPart local part of the QName
48 */
49 public QName(String localPart) {
50 this(emptyString, localPart, emptyString);
51 }
52
53 /**
54 * Constructor for the QName.
55 *
56 * @param namespaceURI namespace URI for the QName
57 * @param localPart local part of the QName.
58 */
59 public QName(String namespaceURI, String localPart) {
60 this(namespaceURI, localPart, emptyString);
61 }
62
63 /**
64 * Constructor for the QName.
65 *
66 * @param namespaceURI Namespace URI for the QName
67 * @param localPart Local part of the QName.
68 * @param prefix Prefix of the QName.
69 */
70 public QName(String namespaceURI, String localPart, String prefix) {
71 this.namespaceURI = (namespaceURI == null)
72 ? emptyString
73 : namespaceURI.intern();
74 if (localPart == null) {
75 throw new IllegalArgumentException("invalid QName local part");
76 } else {
77 this.localPart = localPart.intern();
78 }
79
80 if (prefix == null) {
81 throw new IllegalArgumentException("invalid QName prefix");
82 } else {
83 this.prefix = prefix.intern();
84 }
85 }
86
87 /**
88 * Gets the namespace URI for this QName.
89 *
90 * @return namespace URI
91 */
92 public String getNamespaceURI() {
93 return namespaceURI;
94 }
95
96 /**
97 * Gets the local part for this QName.
98 *
99 * @return the local part
100 */
101 public String getLocalPart() {
102 return localPart;
103 }
104
105 /**
106 * Gets the prefix for this QName.
107 *
108 * @return the prefix
109 */
110 public String getPrefix() {
111 return prefix;
112 }
113
114 /**
115 * Returns a string representation of this QName.
116 *
117 * @return a string representation of the QName
118 */
119 public String toString() {
120
121 return ((namespaceURI == emptyString)
122 ? localPart
123 : '{' + namespaceURI + '}' + localPart);
124 }
125
126 /**
127 * Tests this QName for equality with another object.
128 * <p>
129 * If the given object is not a QName or is null then this method
130 * returns <tt>false</tt>.
131 * <p>
132 * For two QNames to be considered equal requires that both
133 * localPart and namespaceURI must be equal. This method uses
134 * <code>String.equals</code> to check equality of localPart
135 * and namespaceURI. Any class that extends QName is required
136 * to satisfy this equality contract.
137 * <p>
138 * This method satisfies the general contract of the <code>Object.equals</code> method.
139 *
140 * @param obj the reference object with which to compare
141 *
142 * @return <code>true</code> if the given object is identical to this
143 * QName: <code>false</code> otherwise.
144 */
145 public final boolean equals(Object obj) {
146
147 if (obj == this) {
148 return true;
149 }
150
151 if (!(obj instanceof QName)) {
152 return false;
153 }
154
155 if ((namespaceURI == ((QName) obj).namespaceURI)
156 && (localPart == ((QName) obj).localPart)) {
157 return true;
158 }
159
160 return false;
161 }
162
163 /**
164 * Returns a QName holding the value of the specified String.
165 * <p>
166 * The string must be in the form returned by the QName.toString()
167 * method, i.e. "{namespaceURI}localPart", with the "{namespaceURI}"
168 * part being optional.
169 * <p>
170 * This method doesn't do a full validation of the resulting QName.
171 * In particular, it doesn't check that the resulting namespace URI
172 * is a legal URI (per RFC 2396 and RFC 2732), nor that the resulting
173 * local part is a legal NCName per the XML Namespaces specification.
174 *
175 * @param s the string to be parsed
176 * @throws java.lang.IllegalArgumentException If the specified String cannot be parsed as a QName
177 * @return QName corresponding to the given String
178 */
179 public static QName valueOf(String s) {
180
181 if ((s == null) || s.equals("")) {
182 throw new IllegalArgumentException("invalid QName literal");
183 }
184
185 if (s.charAt(0) == '{') {
186 int i = s.indexOf('}');
187
188 if (i == -1) {
189 throw new IllegalArgumentException("invalid QName literal");
190 }
191
192 if (i == s.length() - 1) {
193 throw new IllegalArgumentException("invalid QName literal");
194 } else {
195 return new QName(s.substring(1, i), s.substring(i + 1));
196 }
197 } else {
198 return new QName(s);
199 }
200 }
201
202 /**
203 * Returns a hash code value for this QName object. The hash code
204 * is based on both the localPart and namespaceURI parts of the
205 * QName. This method satisfies the general contract of the
206 * <code>Object.hashCode</code> method.
207 *
208 * @return a hash code value for this Qname object
209 */
210 public final int hashCode() {
211 return namespaceURI.hashCode() ^ localPart.hashCode();
212 }
213
214 /**
215 * Ensure that deserialization properly interns the results.
216 * @param in the ObjectInputStream to be read
217 * @throws IOException if there was a failure in the object input stream
218 * @throws ClassNotFoundException if the class of any sub-objects could
219 * not be found
220 */
221 private void readObject(ObjectInputStream in) throws
222 IOException, ClassNotFoundException {
223 in.defaultReadObject();
224
225 namespaceURI = namespaceURI.intern();
226 localPart = localPart.intern();
227 prefix = prefix.intern();
228 }
229 }