|
Orocos Real-Time Toolkit
2.9.0
|
A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing. More...
#include <rtt/marsh/tinyxml.h>
Public Member Functions | |
| TiXmlHandle (TiXmlNode *_node) | |
| Create a handle from any node (at any depth of the tree.) This can be a null pointer. More... | |
| TiXmlHandle (const TiXmlHandle &ref) | |
| Copy constructor. More... | |
| TiXmlHandle | operator= (const TiXmlHandle &ref) |
| TiXmlHandle | FirstChild () const |
| Return a handle to the first child node. More... | |
| TiXmlHandle | FirstChild (const char *value) const |
| Return a handle to the first child node with the given name. More... | |
| TiXmlHandle | FirstChildElement () const |
| Return a handle to the first child element. More... | |
| TiXmlHandle | FirstChildElement (const char *value) const |
| Return a handle to the first child element with the given name. More... | |
| TiXmlHandle | Child (const char *value, int index) const |
| Return a handle to the "index" child with the given name. More... | |
| TiXmlHandle | Child (int index) const |
| Return a handle to the "index" child. More... | |
| TiXmlHandle | ChildElement (const char *value, int index) const |
| Return a handle to the "index" child element with the given name. More... | |
| TiXmlHandle | ChildElement (int index) const |
| Return a handle to the "index" child element. More... | |
| TiXmlNode * | Node () const |
| Return the handle as a TiXmlNode. This may return null. More... | |
| TiXmlElement * | Element () const |
| Return the handle as a TiXmlElement. This may return null. More... | |
| TiXmlText * | Text () const |
| Return the handle as a TiXmlText. This may return null. More... | |
| TiXmlUnknown * | Unknown () const |
| Return the handle as a TiXmlUnknown. This may return null;. More... | |
A TiXmlHandle is a class that wraps a node pointer with null checks; this is an incredibly useful thing.
Note that TiXmlHandle is not part of the TinyXml DOM structure. It is a separate utility class.
Take an example:
<Document>
<Element attributeA = "valueA">
<Child attributeB = "value1" />
<Child attributeB = "value2" />
</Element>
<Document>
Assuming you want the value of "attributeB" in the 2nd "Child" element, it's very easy to write a lot of code that looks like:
TiXmlElement* root = document.FirstChildElement( "Document" );
if ( root )
{
TiXmlElement* element = root->FirstChildElement( "Element" );
if ( element )
{
TiXmlElement* child = element->FirstChildElement( "Child" );
if ( child )
{
TiXmlElement* child2 = child->NextSiblingElement( "Child" );
if ( child2 )
{
// Finally do something useful.
And that doesn't even cover "else" cases. TiXmlHandle addresses the verbosity of such code. A TiXmlHandle checks for null pointers so it is perfectly safe and correct to use:
TiXmlHandle docHandle( &document );
TiXmlElement* child2 = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", 1 ).Element();
if ( child2 )
{
// do something useful
Which is MUCH more concise and useful.
It is also safe to copy handles - internally they are nothing more than node pointers.
TiXmlHandle handleCopy = handle;
What they should not be used for is iteration:
int i=0;
while ( true )
{
TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).Child( "Child", i ).Element();
if ( !child )
break;
// do something
++i;
}
It seems reasonable, but it is in fact two embedded while loops. The Child method is a linear walk to find the element, so this code would iterate much more than it needs to. Instead, prefer:
TiXmlElement* child = docHandle.FirstChild( "Document" ).FirstChild( "Element" ).FirstChild( "Child" ).Element();
for( child; child; child=child->NextSiblingElement() )
{
// do something
}
|
inline |
|
inline |
| TiXmlHandle RTT::marsh::TiXmlHandle::Child | ( | const char * | value, |
| int | index | ||
| ) | const |
Return a handle to the "index" child with the given name.
The first child is 0, the second 1, etc.
Definition at line 1784 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChild(), and RTT::marsh::TiXmlNode::NextSibling().
| TiXmlHandle RTT::marsh::TiXmlHandle::Child | ( | int | index | ) | const |
Return a handle to the "index" child.
The first child is 0, the second 1, etc.
Definition at line 1765 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChild(), and RTT::marsh::TiXmlNode::NextSibling().
| TiXmlHandle RTT::marsh::TiXmlHandle::ChildElement | ( | const char * | value, |
| int | index | ||
| ) | const |
Return a handle to the "index" child element with the given name.
The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.
Definition at line 1822 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChildElement(), and RTT::marsh::TiXmlNode::NextSiblingElement().
| TiXmlHandle RTT::marsh::TiXmlHandle::ChildElement | ( | int | index | ) | const |
Return a handle to the "index" child element.
The first child element is 0, the second 1, etc. Note that only TiXmlElements are indexed: other types are not counted.
Definition at line 1803 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChildElement(), and RTT::marsh::TiXmlNode::NextSiblingElement().
|
inline |
Return the handle as a TiXmlElement. This may return null.
| TiXmlHandle RTT::marsh::TiXmlHandle::FirstChild | ( | ) | const |
Return a handle to the first child node.
Definition at line 1717 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChild().
| TiXmlHandle RTT::marsh::TiXmlHandle::FirstChild | ( | const char * | value | ) | const |
Return a handle to the first child node with the given name.
Definition at line 1729 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChild().
| TiXmlHandle RTT::marsh::TiXmlHandle::FirstChildElement | ( | ) | const |
Return a handle to the first child element.
Definition at line 1741 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChildElement().
| TiXmlHandle RTT::marsh::TiXmlHandle::FirstChildElement | ( | const char * | value | ) | const |
Return a handle to the first child element with the given name.
Definition at line 1753 of file tinyxml.cpp.
References RTT::marsh::TiXmlNode::FirstChildElement().
|
inline |
|
inline |
|
inline |
|
inline |
Return the handle as a TiXmlUnknown. This may return null;.
1.8.11