The current implementation is subject to change and this class
should be accessed only through published interface methods. However,
the following information is provided to aid in an understanding of how this
class currently works and is provided for debugging purposes only.
This implementation stores information about each node in a series of arrays. Conceptually,
the arrays can be thought of as either String Vectors or int
Vectors although they are implemented using some internal classes. The m_chars
array is conceptually a Vector of chars. The chief arrays of
interest are shown in the following table:
| Array Name | Array Type | Contents |
|---|---|---|
m_exptype |
int | An integer representing a unique value for a Node. The first 6 bits represent the Node type, as shown below. The next 10 bits represent an index into m_namespaceNames. The remaining 16 bits represent an index into m_locNamesPool. Start here. This Vector represents the list of Nodes. |
m_locNamesPool |
String | Local (prefixed) names. Field of m_expandedNameTable. |
m_namespaceNames |
String | Namespace URIs. Field of m_expandedNameTable. |
m_dataOrQName |
int | An index into either m_data or m_valuesOrPrefixes, as explained in the next table. |
m_valuesOrPrefixes |
String | Values and prefixes. |
m_data |
int | Entries here occur in pairs. The use of this array is explained in the next table. |
m_chars |
char | Characters used to form Strings as explained in the next table. |
This table shows how the array values are used for each type of Node supported by
this implementation. An n represents an index into m_namespaceNames
for the namespace URI associated with the attribute or element. It actually consists
of the 10 bits, including the rightmost two bits of the leftmost byte. The eeee
represents an index into m_locNamesPool for the value indicated in the table.
| NodeType | m_exptype | m_dataOrQName | m_data |
|---|---|---|---|
| Attr | 08neeee -0bneeee eeee is local name of attribute. |
No namespace: an index into
m_valuesOrPrefixes pointing to the attribute value.
Namespace: a negative number, the absolute value of which is an index into m_data. |
index: an int containing the index into
m_valuesOrPrefixes for the Attr QName.
index+1: an int containing the index into m_valuesOrPrefixes for the attribute value. |
| Comment | 20000000 | index into m_valuesOrPrefixes
for comment text. |
unused |
| Document | 24000000 | 0 | unused |
| Element | 04neeee -07neeee eeee is local name of element. |
No namespace: 0.
Namespace: an index into m_valuesOrPrefixes pointing to the QName. |
unused |
| Text | 0C000000 | an index into m_data. | index: an int containing starting subscript in
m_chars for the text.
index+1: an int containing the length of the text. |
| ProcessingInstruction | 1C0eeee
eeee is the target name. |
index into m_valuesOrPrefixes
for PI data. |
unused |
| Namespace | 34neeee eeee is namespace prefix. |
index into
m_valuesOrPrefixes pointing to the namespace URI. |
unused |