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java.lang.Objectcom.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.xmlpatterns.QXmlName
public class QXmlName
The QXmlName
class represents the name of an XML node, in an efficient, namespace-aware way. QXmlName
represents the name of an XML node in a way that is both efficient and safe for comparing names. Normally, an XML node represents an XML element or attribute, but QXmlName
can also represent the names of other kinds of nodes, e.g., QAbstractXmlReceiver::processingInstruction()
and QAbstractXmlReceiver::namespaceBinding()
.
The name of an XML node has three components: The namespace URI, the local name, and the prefix. To see what these refer to in XML, consider the following snippet.
<book xmlns:dc='http://purl.org/dc/elements/1.1' xmlns='http://example.com/MyDefault'> <dc:title>Mobey Dick</dc:title> ... </book>For the element named book,
localName()
returns book, namespaceUri()
returns http://example.com/MyDefault, and prefix()
returns an empty string. For the element named title, localName()
returns title, namespaceUri()
returns http://purl.org/dc/elements/1.1, and prefix()
returns dc. To ensure that operations with QXmlName
are efficient, e.g., copying names and comparing them, each instance of QXmlName
is associated with a name pool
, which must be specified at QXmlName
construction time. The three components of the QXmlName
, i.e., the namespace URI, the local name, and the prefix, are stored in the name pool mapped to identifiers so they can be shared. For this reason, the only way to create a valid instance of QXmlName
is to use the class constructor, where the name pool
, local name, namespace URI, and prefix must all be specified.
Note that QXmlName
's default constructor constructs a null instance. It is typically used for allocating unused entries in collections of QXmlName
.
A side effect of associating each instance of QXmlName
with a name pool
is that each instance of QXmlName
is tied to the QXmlNamePool
with which it was created. However, the QXmlName
class does not keep track of the name pool, so all the accessor functions, e.g., namespaceUri()
, prefix()
, localName()
, and toClarkName()
require that the correct name pool be passed to them. Failure to provide the correct name pool to these accessor functions results in undefined behavior.
Note that a name pool
is not an XML namespace. One name pool
can represent instances of QXmlName
from different XML namespaces, and the instances of QXmlName
from one XML namespace can be distributed over multiple name pools
.Comparing QXmlNames
To determine what a QXmlName
refers to, the namespace URI and the local name are used. The prefix is not used because the prefix is simply a shorthand name for use in place of the normally much longer namespace URI. Nor is the prefix used in name comparisons. For example, the following two element nodes represent the same element and compare equal.
<svg xmlns="http://www.w3.org/2000/svg"/>
<x:svg xmlns:x="http://www.w3.org/2000/svg"/>Although the second name has the prefix x, the two names compare equal as instances of
QXmlName
, because the prefix is not used in the comparison. A local name can never be an empty string, although the prefix and namespace URI can. If the prefix is not empty, the namespace URI cannot be empty. Local names and prefixes must be valid NCNames, e.g., abc.def or abc123.
QXmlName
represents what is sometimes called an expanded QName, or simply a QName.
Nested Class Summary |
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Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9 |
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
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com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal |
Field Summary |
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Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
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currentSender |
Constructor Summary | |
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QXmlName()
Constructs an uninitialized QXmlName . |
|
QXmlName(QXmlNamePool namePool,
java.lang.String localName)
Equivalent to calling QXmlName(namePool, localName, null, null) |
|
QXmlName(QXmlNamePool namePool,
java.lang.String localName,
java.lang.String namespaceURI)
Equivalent to calling QXmlName(namePool, localName, namespaceURI, null); |
|
QXmlName(QXmlNamePool namePool,
java.lang.String localName,
java.lang.String namespaceURI,
java.lang.String prefix)
Constructs a QXmlName instance that inserts localName ,
namespaceURI and prefix into namePool if they aren't
already there. |
Method Summary | |
---|---|
QXmlName |
clone()
|
static boolean |
isNCName(java.lang.String candidate)
Returns true if candidate is an NCName. |
boolean |
isNull()
Returns true if this QXmlName is not initialized with a valid combination of namespace URI, local name, and prefix. |
java.lang.String |
localName(QXmlNamePool query)
Returns the local name. |
java.lang.String |
namespaceUri(QXmlNamePool query)
Returns the namespace URI. |
java.lang.String |
prefix(QXmlNamePool query)
Returns the prefix. |
java.lang.String |
toClarkName(QXmlNamePool query)
Returns this QXmlName formatted as a Clark Name. |
Methods inherited from class com.trolltech.qt.QtJambiObject |
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dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal |
---|
__qt_signalInitialization |
Methods inherited from class java.lang.Object |
---|
getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Constructor Detail |
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public QXmlName()
QXmlName
. To build a valid QXmlName
, you normally use the other constructor, which takes a name pool
, namespace URI, local name, and prefix as parameters. But you can also use this constructor to build a null QXmlName
and then assign an existing QXmlName
to it. isNull()
.
public QXmlName(QXmlNamePool namePool, java.lang.String localName, java.lang.String namespaceURI, java.lang.String prefix)
QXmlName
instance that inserts localName
,
namespaceURI
and prefix
into namePool
if they aren't
already there. The accessor functions namespaceUri()
, prefix()
,
localName()
, and toClarkName()
must be passed the namePool
used here, so the namePool
must remain in scope while the
accessor functions might be used. However, two instances can
be compared with ==
or !=
and copied without the
namePool
.
The user guarantees that the string components are valid for a
QName
. In particular, the local name, and the prefix (if present),
must be valid NCNames
The function isNCName()
can be used to test validity
of these names. The namespace URI should be an absolute URI.
QUrl.isRelative()
can be used to test whether the namespace URI
is relative or absolute. Finally, providing a prefix is not valid
when no namespace URI is provided.
namePool
is not copied. Nor is the reference to it retained
in this instance. This constructor inserts the three strings
into namePool
.
public QXmlName(QXmlNamePool namePool, java.lang.String localName, java.lang.String namespaceURI)
public QXmlName(QXmlNamePool namePool, java.lang.String localName)
Method Detail |
---|
public final boolean isNull()
QXmlName
is not initialized with a valid combination of namespace URI, local name, and prefix. A valid local name is always required. The prefix and namespace URI can be empty, but if the prefix is not empty, the namespace URI must not be empty. Local names and prefixes must be valid NCNames, e.g., abc.def or abc123.
public final java.lang.String localName(QXmlNamePool query)
Note that for efficiency, the local name string is not stored in the QXmlName
but in the QXmlNamePool
that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the local name.
public final java.lang.String namespaceUri(QXmlNamePool query)
Note that for efficiency, the namespace URI string is not stored in the QXmlName
but in the QXmlNamePool
that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the namespace URI.
public final java.lang.String prefix(QXmlNamePool query)
Note that for efficiency, the prefix string is not stored in the QXmlName
but in the QXmlNamePool
that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the prefix.
public final java.lang.String toClarkName(QXmlNamePool query)
QXmlName
formatted as a Clark Name. For example, if the local name is html, the prefix is x, and the namespace URI is http://www.w3.org/1999/xhtml/, then the Clark Name returned is:{http://www.w3.org/1999/xhtml/}x:html.If the local name is MyWidget and the namespace is empty, the Clark Name returned is:
MyWidgetNote that for efficiency, the namespace URI, local name, and prefix strings are not stored in the
QXmlName
but in the QXmlNamePool
that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the three string components. This function can be useful for debugging.
public static boolean isNCName(java.lang.String candidate)
public QXmlName clone()
clone
in class java.lang.Object
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