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The QName.java Java example source code
/*
* Copyright (c) 2003, 2006, 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.xml.namespace;
import java.io.Serializable;
import java.security.AccessController;
import java.security.PrivilegedAction;
import javax.xml.XMLConstants;
/**
* <p>QName represents a qualified name
* as defined in the XML specifications: <a
* href="http://www.w3.org/TR/xmlschema-2/#QName">XML Schema Part2:
* Datatypes specification</a>,
*
* <p>The value of a QName contains a Namespace
* URI</strong>, local part and
* <strong>prefix.
*
* <p>The prefix is included in QName to retain lexical
* information <strong>when present in an {@link
* javax.xml.transform.Source XML input source}. The prefix is
* <strong>NOT used in {@link #equals(Object)
* QName.equals(Object)} or to compute the {@link #hashCode()
* QName.hashCode()}. Equality and the hash code are defined using
* <strong>only the Namespace URI and local part.
*
* <p>If not specified, the Namespace URI is set to {@link
* javax.xml.XMLConstants#NULL_NS_URI XMLConstants.NULL_NS_URI}.
* If not specified, the prefix is set to {@link
* javax.xml.XMLConstants#DEFAULT_NS_PREFIX
* XMLConstants.DEFAULT_NS_PREFIX}.</p>
*
* <p>QName is immutable.
*
* @author <a href="mailto:Jeff.Suttor@Sun.com">Jeff Suttor
* @version $Revision: 1.8 $, $Date: 2010/03/18 03:06:17 $
* @see <a href="http://www.w3.org/TR/xmlschema-2/#QName">
* XML Schema Part2: Datatypes specification</a>
* @see <a href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">
* Namespaces in XML</a>
* @see <a href="http://www.w3.org/XML/xml-names-19990114-errata">
* Namespaces in XML Errata</a>
* @since 1.5
*/
public class QName implements Serializable {
/**
* <p>Stream Unique Identifier.
*
* <p>Due to a historical defect, QName was released with multiple
* serialVersionUID values even though its serialization was the
* same.</p>
*
* <p>To workaround this issue, serialVersionUID is set with either
* a default value or a compatibility value. To use the
* compatiblity value, set the system property:</p>
*
* <code>com.sun.xml.namespace.QName.useCompatibleSerialVersionUID=1.0
*
* <p>This workaround was inspired by classes in the javax.management
* package, e.g. ObjectName, etc.
* See CR6267224 for original defect report.</p>
*/
private static final long serialVersionUID;
/**
* <p>Default serialVersionUID value.
*/
private static final long defaultSerialVersionUID = -9120448754896609940L;
/**
* <p>Compatibility serialVersionUID value.
*/
private static final long compatibleSerialVersionUID = 4418622981026545151L;
/**
* <p>Flag to use default or campatible serialVersionUID.
*/
private static boolean useDefaultSerialVersionUID = true;
static {
try {
// use a privileged block as reading a system property
String valueUseCompatibleSerialVersionUID = (String) AccessController.doPrivileged(
new PrivilegedAction() {
public Object run() {
return System.getProperty("com.sun.xml.namespace.QName.useCompatibleSerialVersionUID");
}
}
);
useDefaultSerialVersionUID = (valueUseCompatibleSerialVersionUID != null && valueUseCompatibleSerialVersionUID.equals("1.0")) ? false : true;
} catch (Exception exception) {
// use default if any Exceptions
useDefaultSerialVersionUID = true;
}
// set serialVersionUID to desired value
if (useDefaultSerialVersionUID) {
serialVersionUID = defaultSerialVersionUID;
} else {
serialVersionUID = compatibleSerialVersionUID;
}
}
/**
* <p>Namespace URI of this QName.
*/
private final String namespaceURI;
/**
* <p>local part of this QName.
*/
private final String localPart;
/**
* <p>prefix of this QName.
*/
private final String prefix;
/**
* <p>QName constructor specifying the Namespace URI
* and local part.</p>
*
* <p>If the Namespace URI is null, it is set to
* {@link javax.xml.XMLConstants#NULL_NS_URI
* XMLConstants.NULL_NS_URI}. This value represents no
* explicitly defined Namespace as defined by the <a
* href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">Namespaces
* in XML</a> specification. This action preserves compatible
* behavior with QName 1.0. Explicitly providing the {@link
* javax.xml.XMLConstants#NULL_NS_URI
* XMLConstants.NULL_NS_URI} value is the preferred coding
* style.</p>
*
* <p>If the local part is null an
* <code>IllegalArgumentException is thrown.
* A local part of "" is allowed to preserve
* compatible behavior with QName 1.0. </p>
*
* <p>When using this constructor, the prefix is set to {@link
* javax.xml.XMLConstants#DEFAULT_NS_PREFIX
* XMLConstants.DEFAULT_NS_PREFIX}.</p>
*
* <p>The Namespace URI is not validated as a
* <a href="http://www.ietf.org/rfc/rfc2396.txt">URI reference.
* The local part is not validated as a
* <a href="http://www.w3.org/TR/REC-xml-names/#NT-NCName">NCName
* as specified in <a href="http://www.w3.org/TR/REC-xml-names/">Namespaces
* in XML</a>.
*
* @param namespaceURI Namespace URI of the <code>QName
* @param localPart local part of the <code>QName
*
* @throws IllegalArgumentException When <code>localPart is
* <code>null
*
* @see #QName(String namespaceURI, String localPart, String
* prefix) QName(String namespaceURI, String localPart, String
* prefix)
*/
public QName(final String namespaceURI, final String localPart) {
this(namespaceURI, localPart, XMLConstants.DEFAULT_NS_PREFIX);
}
/**
* <p>QName constructor specifying the Namespace URI,
* local part and prefix.</p>
*
* <p>If the Namespace URI is null, it is set to
* {@link javax.xml.XMLConstants#NULL_NS_URI
* XMLConstants.NULL_NS_URI}. This value represents no
* explicitly defined Namespace as defined by the <a
* href="http://www.w3.org/TR/REC-xml-names/#ns-qualnames">Namespaces
* in XML</a> specification. This action preserves compatible
* behavior with QName 1.0. Explicitly providing the {@link
* javax.xml.XMLConstants#NULL_NS_URI
* XMLConstants.NULL_NS_URI} value is the preferred coding
* style.</p>
*
* <p>If the local part is null an
* <code>IllegalArgumentException is thrown.
* A local part of "" is allowed to preserve
* compatible behavior with QName 1.0. </p>
*
* <p>If the prefix is null, an
* <code>IllegalArgumentException is thrown. Use {@link
* javax.xml.XMLConstants#DEFAULT_NS_PREFIX
* XMLConstants.DEFAULT_NS_PREFIX} to explicitly indicate that no
* prefix is present or the prefix is not relevant.</p>
*
* <p>The Namespace URI is not validated as a
* <a href="http://www.ietf.org/rfc/rfc2396.txt">URI reference.
* The local part and prefix are not validated as a
* <a href="http://www.w3.org/TR/REC-xml-names/#NT-NCName">NCName
* as specified in <a href="http://www.w3.org/TR/REC-xml-names/">Namespaces
* in XML</a>.
*
* @param namespaceURI Namespace URI of the <code>QName
* @param localPart local part of the <code>QName
* @param prefix prefix of the <code>QName
*
* @throws IllegalArgumentException When <code>localPart
* or <code>prefix is null
*/
public QName(String namespaceURI, String localPart, String prefix) {
// map null Namespace URI to default
// to preserve compatibility with QName 1.0
if (namespaceURI == null) {
this.namespaceURI = XMLConstants.NULL_NS_URI;
} else {
this.namespaceURI = namespaceURI;
}
// local part is required.
// "" is allowed to preserve compatibility with QName 1.0
if (localPart == null) {
throw new IllegalArgumentException(
"local part cannot be \"null\" when creating a QName");
}
this.localPart = localPart;
// prefix is required
if (prefix == null) {
throw new IllegalArgumentException(
"prefix cannot be \"null\" when creating a QName");
}
this.prefix = prefix;
}
/**
* <p>QName constructor specifying the local part.
*
* <p>If the local part is null an
* <code>IllegalArgumentException is thrown.
* A local part of "" is allowed to preserve
* compatible behavior with QName 1.0. </p>
*
* <p>When using this constructor, the Namespace URI is set to
* {@link javax.xml.XMLConstants#NULL_NS_URI
* XMLConstants.NULL_NS_URI} and the prefix is set to {@link
* javax.xml.XMLConstants#DEFAULT_NS_PREFIX
* XMLConstants.DEFAULT_NS_PREFIX}.</p>
*
* <p>In an XML context, all Element and Attribute names exist
* in the context of a Namespace. Making this explicit during the
* construction of a <code>QName helps prevent hard to
* diagnosis XML validity errors. The constructors {@link
* #QName(String namespaceURI, String localPart) QName(String
* namespaceURI, String localPart)} and
* {@link #QName(String namespaceURI, String localPart, String prefix)}
* are preferred.</em>
*
* <p>The local part is not validated as a
* <a href="http://www.w3.org/TR/REC-xml-names/#NT-NCName">NCName
* as specified in <a href="http://www.w3.org/TR/REC-xml-names/">Namespaces
* in XML</a>.
*
* @param localPart local part of the <code>QName
*
* @throws IllegalArgumentException When <code>localPart is
* <code>null
*
* @see #QName(String namespaceURI, String localPart) QName(String
* namespaceURI, String localPart)
* @see #QName(String namespaceURI, String localPart, String
* prefix) QName(String namespaceURI, String localPart, String
* prefix)
*/
public QName(String localPart) {
this(
XMLConstants.NULL_NS_URI,
localPart,
XMLConstants.DEFAULT_NS_PREFIX);
}
/**
* <p>Get the Namespace URI of this QName.
*
* @return Namespace URI of this <code>QName
*/
public String getNamespaceURI() {
return namespaceURI;
}
/**
* <p>Get the local part of this QName.
*
* @return local part of this <code>QName
*/
public String getLocalPart() {
return localPart;
}
/**
* <p>Get the prefix of this QName.
*
* <p>The prefix assigned to a QName might
* <strong>NOT be valid in a different
* context. For example, a <code>QName may be assigned a
* prefix in the context of parsing a document but that prefix may
* be invalid in the context of a different document.</p>
*
* @return prefix of this <code>QName
*/
public String getPrefix() {
return prefix;
}
/**
* <p>Test this QName for equality with another
* <code>Object.
*
* <p>If the Object to be tested is not a
* <code>QName or is null, then this method
* returns <code>false.
*
* <p>Two QNames are considered equal if and only if
* both the Namespace URI and local part are equal. This method
* uses <code>String.equals() to check equality of the
* Namespace URI and local part. The prefix is
* <strong>NOT used to determine equality.
*
* <p>This method satisfies the general contract of {@link
* java.lang.Object#equals(Object) Object.equals(Object)}</p>
*
* @param objectToTest the <code>Object to test for
* equality with this <code>QName
* @return <code>true if the given Object is
* equal to this <code>QName else false
*/
public final boolean equals(Object objectToTest) {
if (objectToTest == this) {
return true;
}
if (objectToTest == null || !(objectToTest instanceof QName)) {
return false;
}
QName qName = (QName) objectToTest;
return localPart.equals(qName.localPart)
&& namespaceURI.equals(qName.namespaceURI);
}
/**
* <p>Generate the hash code for this QName.
*
* <p>The hash code is calculated using both the Namespace URI and
* the local part of the <code>QName. The prefix is
* <strong>NOT used to calculate the hash
* code.</p>
*
* <p>This method satisfies the general contract of {@link
* java.lang.Object#hashCode() Object.hashCode()}.</p>
*
* @return hash code for this <code>QName Object
*/
public final int hashCode() {
return namespaceURI.hashCode() ^ localPart.hashCode();
}
/**
* <p>String representation of this
* <code>QName.
*
* <p>The commonly accepted way of representing a QName
* as a <code>String was
* <a href="http://jclark.com/xml/xmlns.htm">defined
* by James Clark. Although this is not a <em>standard
* specification, it is in common use, e.g. {@link
* javax.xml.transform.Transformer#setParameter(String name, Object value)}.
* This implementation represents a <code>QName as:
* "{" + Namespace URI + "}" + local part. If the Namespace URI
* <code>.equals(XMLConstants.NULL_NS_URI), only the
* local part is returned. An appropriate use of this method is
* for debugging or logging for human consumption.</p>
*
* <p>Note the prefix value is NOT
* returned as part of the <code>String representation.
*
* <p>This method satisfies the general contract of {@link
* java.lang.Object#toString() Object.toString()}.</p>
*
* @return <code>String representation of this QName
*/
public String toString() {
if (namespaceURI.equals(XMLConstants.NULL_NS_URI)) {
return localPart;
} else {
return "{" + namespaceURI + "}" + localPart;
}
}
/**
* <p>QName derived from parsing the formatted
* <code>String.
*
* <p>If the String is null or does not conform to
* {@link #toString() QName.toString()} formatting, an
* <code>IllegalArgumentException is thrown.
*
* <p>The String MUST be in the
* form returned by {@link #toString() QName.toString()}.</em>
*
* <p>The commonly accepted way of representing a QName
* as a <code>String was
* <a href="http://jclark.com/xml/xmlns.htm">defined
* by James Clark. Although this is not a <em>standard
* specification, it is in common use, e.g. {@link
* javax.xml.transform.Transformer#setParameter(String name, Object value)}.
* This implementation parses a <code>String formatted
* as: "{" + Namespace URI + "}" + local part. If the Namespace
* URI <code>.equals(XMLConstants.NULL_NS_URI), only the
* local part should be provided.</p>
*
* <p>The prefix value CANNOT be
* represented in the <code>String and will be set to
* {@link javax.xml.XMLConstants#DEFAULT_NS_PREFIX
* XMLConstants.DEFAULT_NS_PREFIX}.</p>
*
* <p>This method does not do full validation of the resulting
* <code>QName.
* <p>The Namespace URI is not validated as a
* <a href="http://www.ietf.org/rfc/rfc2396.txt">URI reference.
* The local part is not validated as a
* <a href="http://www.w3.org/TR/REC-xml-names/#NT-NCName">NCName
* as specified in
* <a href="http://www.w3.org/TR/REC-xml-names/">Namespaces in XML.
*
* @param qNameAsString <code>String representation
* of the <code>QName
*
* @throws IllegalArgumentException When <code>qNameAsString is
* <code>null or malformed
*
* @return <code>QName corresponding to the given String
* @see #toString() QName.toString()
*/
public static QName valueOf(String qNameAsString) {
// null is not valid
if (qNameAsString == null) {
throw new IllegalArgumentException(
"cannot create QName from \"null\" or \"\" String");
}
// "" local part is valid to preserve compatible behavior with QName 1.0
if (qNameAsString.length() == 0) {
return new QName(
XMLConstants.NULL_NS_URI,
qNameAsString,
XMLConstants.DEFAULT_NS_PREFIX);
}
// local part only?
if (qNameAsString.charAt(0) != '{') {
return new QName(
XMLConstants.NULL_NS_URI,
qNameAsString,
XMLConstants.DEFAULT_NS_PREFIX);
}
// Namespace URI improperly specified?
if (qNameAsString.startsWith("{" + XMLConstants.NULL_NS_URI + "}")) {
throw new IllegalArgumentException(
"Namespace URI .equals(XMLConstants.NULL_NS_URI), "
+ ".equals(\"" + XMLConstants.NULL_NS_URI + "\"), "
+ "only the local part, "
+ "\""
+ qNameAsString.substring(2 + XMLConstants.NULL_NS_URI.length())
+ "\", "
+ "should be provided.");
}
// Namespace URI and local part specified
int endOfNamespaceURI = qNameAsString.indexOf('}');
if (endOfNamespaceURI == -1) {
throw new IllegalArgumentException(
"cannot create QName from \""
+ qNameAsString
+ "\", missing closing \"}\"");
}
return new QName(
qNameAsString.substring(1, endOfNamespaceURI),
qNameAsString.substring(endOfNamespaceURI + 1),
XMLConstants.DEFAULT_NS_PREFIX);
}
}
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