dleslie 00/07/28 09:21:10
Modified: xdocs/sources/design design2_0_0.xml
Log:
Fixed links and added TOC
Revision Changes Path
1.3 +51 -37 xml-xalan/xdocs/sources/design/design2_0_0.xml
Index: design2_0_0.xml
===================================================================
RCS file: /home/cvs/xml-xalan/xdocs/sources/design/design2_0_0.xml,v
retrieving revision 1.2
retrieving revision 1.3
diff -u -r1.2 -r1.3
--- design2_0_0.xml 2000/07/28 13:30:07 1.2
+++ design2_0_0.xml 2000/07/28 16:21:09 1.3
@@ -2,13 +2,27 @@
<!DOCTYPE s1 SYSTEM "sbk:/style/dtd/document.dtd">
<s1 title="Xalan-J 2.0 Design">
<p><link>Xalan-J 2.0 Design</link><img src="xmllogo.gif"
alt="xmllogo.gif"/></p>
+ <p>Author: Scott Boag<br/>State: In Progress</p>
<ul>
- <li>Author: Scott Boag</li>
- <li>State: In Progress</li>
+ <li><link anchor="intro">Introduction</link></li>
+ <li><link anchor="overarch">Overview of Architecture</link></li>
+ <li><link anchor="process">Process Module</link></li>
+ <li><link anchor="templates">Templates Module</link></li>
+ <li><link anchor="transformer">Transformer Module</link></li>
+ <ul>
+ <li><link anchor="stree">Stree Module</link></li>
+ <li><link anchor="extensions">Extensions Module</link></li>
+ </ul>
+ <li><link anchor="xpath">XPath Module</link></li>
+ <ul><li><link anchor="xpathdbconn">XPath Database
Connection</link></li></ul>
+ <li><link anchor="utils">Utils Package</link></li>
+ <li><link anchor="other">Other Packages</link></li>
+ <li><link anchor="coding">Coding Conventions</link></li>
+ <li><link anchor="open">Open Issues</link></li>
<li><jump href="http://xml.apache.org/xalan-j/apidocs/index.html";>Xalan-J
2.0 Javadoc</jump></li>
- </ul>
+ </ul><anchor name="intro"/>
<s2 title="Introduction">
- <p><link idref="intro">Introduction</link></p>
+ <p><link>Introduction</link></p>
<p>This document presents the basic design for Xalan-J 2.0, which is a
<jump
href="http://www.awl.com/cseng/titles/0-201-89542-0/techniques/refactoring.htm";>refactoring</jump>
and redesign of the Xalan-J 1.x processor. The main goals of
this redesign are
@@ -45,38 +59,38 @@
expect that the code will be faster once this work is
complete.</li>
</ol>
<p>How well we've achieved the goals will be measured by feedback from
the
- <link
anchor="http://xml-archive.webweaving.org/xml-archive-xalan";>Xalan-dev</link>
list, and by software metrics tools.</p>
+ <jump
href="http://xml-archive.webweaving.org/xml-archive-xalan";>Xalan-dev</jump>
list, and by software metrics tools.</p>
<p>Please note that the diagrams in this design document are meant to
be
useful abstractions, and may not always be exact.</p>
- </s2>
+ </s2><anchor name="overarch"/>
<s2 title="Overview of Architecture">
- <p><link idref="overview">Overview of Architecture</link></p>
+ <p><link>Overview of Architecture</link></p>
<p>Xalan 2.0 is divided into four major modules, and various smaller
modules. The main modules are:</p>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/processor/package-summary.html";>org.apache.xalan.process</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/processor/package-summary.html";>org.apache.xalan.process</jump></code></label>
<item>The module that processes the stylesheet, and provides
the main
entry point into Xalan.</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/templates/package-summary.html";>org.apache.xalan.templates</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/templates/package-summary.html";>org.apache.xalan.templates</jump></code></label>
<item>The module that defines the stylesheet structures,
including the
Stylesheet object, template element instructions, and
Attribute Value
Templates. </item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/package-summary.html";>org.apache.xalan.transformer</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/package-summary.html";>org.apache.xalan.transformer</jump></code></label>
<item>The module that applies the source tree to the Templates,
and
produces a result tree.</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xpath/package-summary.html";>org.apache.xpath</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xpath/package-summary.html";>org.apache.xpath</jump></code></label>
<item>The module that processes both XPath expressions, and
XSLT Match
patterns.</item>
</gloss>
<p>In addition to the above modules, Xalan implements the
- <link anchor="http://trax.openxml.org/";>TrAX</link> interfaces,
and depends on the
- <link
anchor="http://www.megginson.com/SAX/Java/index.html";>SAX2</link> and <link
anchor="http://www.w3.org/TR/DOM-Level-2/";>DOM</link> packages.
+ <jump href="http://trax.openxml.org/";>TrAX</jump> interfaces,
and depends on the
+ <jump href="http://www.megginson.com/SAX/Java/index.html";>SAX2</jump>
and <jump href="http://www.w3.org/TR/DOM-Level-2/";>DOM</jump> packages.
</p><p><img src="trax.gif" alt="trax.gif"/></p><p>There is also a general
utilities package that contains both XML utility
classes such as QName, but generally useful classes such as
StringToIntTable.</p>
@@ -86,41 +100,41 @@
<p>In addition to the above packages, there are the following
additional
packages:</p>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/client/package-summary.html";>org.apache.xalan.client</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/client/package-summary.html";>org.apache.xalan.client</jump></code></label>
<item>This package has a client applet. I suspect this should
be moved
into the samples directory.</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/extensions/package-summary.html";>org.apache.xalan.extensions</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/extensions/package-summary.html";>org.apache.xalan.extensions</jump></code></label>
<item>This holds classes belonging to the Xalan extensions
mechanism,
which allows Java code and script to be called from within a
stylesheet.</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/lib/package-summary.html";>org.apache.xalan.lib</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/lib/package-summary.html";>org.apache.xalan.lib</jump></code></label>
<item>This is the built-in Xalan extensions library, which holds
extensions such as Redirect (which allows a stylesheet to
produce multiple
output files).</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/res/package-summary.html";>org.apache.xalan.res</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/res/package-summary.html";>org.apache.xalan.res</jump></code></label>
<item>This holds resource files needed by Xalan, such as error
message
resources.</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/trace/package-summary.html";>org.apache.xalan.trace</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/trace/package-summary.html";>org.apache.xalan.trace</jump></code></label>
<item>This package contains classes and interfaces that allow a
caller to
add trace listeners to the transformation, allowing an
interface to XSLT
debuggers and similar tools.</item>
</gloss>
<gloss>
- <label><code><link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/xslt/package-summary.html";>org.apache.xalan.xslt</link></code></label>
+ <label><code><jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/xslt/package-summary.html";>org.apache.xalan.xslt</jump></code></label>
<item>This package is for backwards compatibility with
applications that
depend on Xalan 1.x interfaces.</item>
</gloss>
<p>A more conceptual view of this architecture is as follows:</p><p><img
src="conceptual.gif" alt="Picture of conceptual
architecture."/></p></s2><anchor name="process"/>
<s2 title="Process Module">
- <p><link idref="process">Process Module</link></p>
+ <p><link>Process Module</link></p>
<p>The <code>org.apache.xalan.process</code> module implements the
<code>org.apache.xalan.trax.Processor</code> interface, which
provides a
factory method for creating a concrete Processor instance, and
provides methods
@@ -159,7 +173,7 @@
<p><img src="process.gif" alt="process.gif"/></p>
</s2><anchor name="templates"/>
<s2 title="Templates Module">
- <p><link idref="templates">Templates Module</link></p>
+ <p><link>Templates Module</link></p>
<p>The <code>org.apache.xalan.templates</code> module implements the
<code>org.apache.xalan.trax.Templates</code> interface, and
defines a set of
classes that represent a Stylesheet. The primary purpose of
this module is to
@@ -387,8 +401,8 @@
</table>
</s2><anchor name="transformer"/>
<s2 title="Transformer Module">
- <p><link idref="transformer">Transformer Module</link></p>
- <p>The <link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/package-summary.html";>Transformer</link>
module is in charge of run-time transformations. The <link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/TransformerImpl.html";>TransformerImpl</link>
object, which implements the TrAX <link
anchor="http://trax.openxml.org/javadoc/trax/Transformer.html";>Transformer</link>
interface, and has an association with a <link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/templates/StylesheetRoot.html";>StylesheetRoot</link>
object, begins the processing of the source tree (or provides a <link
anchor="http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/ContentHandler.html";>ContentHandler</link>
reference), and performs the transformation. The Transformer package does as
much of the transformation as it can, but element level operations are
generally performed in the <link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/temp
lates/ElemTemplateElement.html#execute(org.apache.xalan.transformer.TransformerImpl,
org.w3c.dom.Node,
org.apache.xalan.utils.QName)">ElemTemplateElement.execute(...)</link>
methods.</p><p>Result Tree events are fed into a <link
anchor="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/ResultTreeHandler.html";>ResultTreeHandler</link>
object, which acts as a layer between the direct calls to the result
+ <p><link>Transformer Module</link></p>
+ <p>The <jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/package-summary.html";>Transformer</jump>
module is in charge of run-time transformations. The <jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/TransformerImpl.html";>TransformerImpl</jump>
object, which implements the TrAX <jump
href="http://trax.openxml.org/javadoc/trax/Transformer.html";>Transformer</jump>
interface, and has an association with a <jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/templates/StylesheetRoot.html";>StylesheetRoot</jump>
object, begins the processing of the source tree (or provides a <jump
href="http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/ContentHandler.html";>ContentHandler</jump>
reference), and performs the transformation. The Transformer package does as
much of the transformation as it can, but element level operations are
generally performed in the <jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/templates/ElemTe
mplateElement.html#execute(org.apache.xalan.transformer.TransformerImpl,
org.w3c.dom.Node,
org.apache.xalan.utils.QName)">ElemTemplateElement.execute(...)</jump>
methods.</p><p>Result Tree events are fed into a <jump
href="http://xml.apache.org/xalan-j/apidocs/org/apache/xalan/transformer/ResultTreeHandler.html";>ResultTreeHandler</jump>
object, which acts as a layer between the direct calls to the result
tree content handler (often a Serializer), and the Transformer. For one
thing,
we have to delay the call to
startElement(name, atts) because of the
@@ -400,8 +414,8 @@
the node count is based on its position in the cache list. The
CountersTable class is a table of counters, keyed by ElemNumber objects, each
of which has a list of Counter
objects.</item></gloss><gloss><label>KeyIterator, KeyManager, and
KeyTable</label><item>These classes handle mapping of keys declared with the
xsl:key element.</item></gloss><gloss><label>TransformState</label><item>This
interface is meant to be used by a consumer of SAX2 events produced by Xalan,
and enables the consumer
to get information about the state of the transform. It
- is primarily intended as a tooling interface.</item></gloss><p>Even though
the following modules are defined in the org.apache.xalan package, instead of
the transformer package, they are defined in this section as they are mostly
related to runtime transformation.</p>
- <s3 title="Stree Module"><p><link idref="stree">Stree Module [And
discussions about streaming]</link></p><p>The Stree module implements the
default <link anchor="http://www.w3.org/TR/xpath#data-model";>Source Tree
</link> for Xalan, that is to be transformed. It implements read-only <link
anchor="http://www.w3.org/TR/DOM-Level-2/";>DOM2</link> interfaces, and provides
some information needed for fast transforms, such as document order indexes.
It also attempts to allow a streaming transform by launching the transform on a
secondary thread as soon as the SAX2 <link
anchor="http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/ContentHandler.html#startDocument()">StartDocument</link>
event has occurred. When the transform requests a node, and node is not
present, the getFirstChild and GetNextSibling methods will wait until the child
node has arrived, or an <link
anchor="http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.S
tring)">endElement</link> event has occurred.</p><p>Note that the secondary
thread is an issue. It would be better to do the same thing as described above
on a single thread, but using the parser in 'pull' mode, or simply with a
parseNext method so the parse would occur in blocks.</p><p>This kind of
streaming is not perfect because it still requires an entire source tree to be
concretely built. There have been a lot of good discussions on the xalan-dev
list about how to do static analysis of a stylesheet, and be able to allocate
only the nodes needed by the transform, while they are needed (or not allocate
source objects at all).</p><p>Vincent-Olivier Arsenault <[EMAIL
PROTECTED]> has proposed the following design:</p><p>By looking at the
stylesheet you know how streamable it is (of course this
+ is primarily intended as a tooling interface.</item></gloss><p>Even though
the following modules are defined in the org.apache.xalan package, instead of
the transformer package, they are defined in this section as they are mostly
related to runtime transformation.</p><anchor name="stree"/>
+ <s3 title="Stree Module"><p><link>Stree Module [And discussions about
streaming]</link></p><p>The Stree module implements the default <jump
href="http://www.w3.org/TR/xpath#data-model";>Source Tree </jump> for Xalan,
that is to be transformed. It implements read-only <jump
href="http://www.w3.org/TR/DOM-Level-2/";>DOM2</jump> interfaces, and provides
some information needed for fast transforms, such as document order indexes.
It also attempts to allow a streaming transform by launching the transform on a
secondary thread as soon as the SAX2 <jump
href="http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/ContentHandler.html#startDocument()">StartDocument</jump>
event has occurred. When the transform requests a node, and node is not
present, the getFirstChild and GetNextSibling methods will wait until the child
node has arrived, or an <jump
href="http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/ContentHandler.html#endElement(java.lang.String,%20java.lang.String,%20java.lang.String)">endElement</ju
mp> event has occurred.</p><p>Note that the secondary thread is an issue. It
would be better to do the same thing as described above on a single thread, but
using the parser in 'pull' mode, or simply with a parseNext method so the parse
would occur in blocks.</p><p>This kind of streaming is not perfect because it
still requires an entire source tree to be concretely built. There have been a
lot of good discussions on the xalan-dev list about how to do static analysis
of a stylesheet, and be able to allocate only the nodes needed by the
transform, while they are needed (or not allocate source objects at
all).</p><p>Vincent-Olivier Arsenault <[EMAIL PROTECTED]> has proposed
the following design:</p><p>By looking at the stylesheet you know how
streamable it is (of course this
needs strict adherence to the xslt recommendation). since there's a root
template and no <xsl:apply-templates/> you can build your context list
containing only absolute xpath which means nodes get out of context
@@ -440,37 +454,37 @@
<li>the streaming context xpath (triggers streaming of the buffer to the
output).</li>
-</ol>
-</s3><s3 title="Extensions Module"><p><link idref="extensions">Extensions
Module</link></p><p>This package contains an implementation of Xalan Extension
Mechanism, which uses the <link
anchor="http://oss.software.ibm.com/developerworks/opensource/bsf/";>Bean
Scripting Framework</link>.
+</ol><anchor name="extensions"/>
+</s3><s3 title="Extensions Module"><p><link>Extensions
Module</link></p><p>This package contains an implementation of Xalan Extension
Mechanism, which uses the <jump
href="http://oss.software.ibm.com/developerworks/opensource/bsf/";>Bean
Scripting Framework</jump>.
-The Bean Scripting Framework (BSF) is an architecture for incorporating
scripting into Java applications and applets. Scripting languages such as
Netscape Rhino (Javascript), VBScript, Perl, Tcl, Python, NetRexx and Rexx can
be used to augment XSLT's functionality. In addition, the Xalan extension
mechanism allows use of Java classes. See the <link
anchor="http://xml.apache.org/xalan/extensions.html";>Xalan-J 1 extension
documentation</link> for a description of using extensions in a stylesheet.
Please note that the W3C XSL Working Group is working on a specification for
standard extension bindings, and this module will change to follow that
specification. </p><p>[More needed... -sb]</p></s3></s2><anchor name="xpath"/>
+The Bean Scripting Framework (BSF) is an architecture for incorporating
scripting into Java applications and applets. Scripting languages such as
Netscape Rhino (Javascript), VBScript, Perl, Tcl, Python, NetRexx and Rexx can
be used to augment XSLT's functionality. In addition, the Xalan extension
mechanism allows use of Java classes. See the <jump
href="http://xml.apache.org/xalan/extensions.html";>Xalan-J 1 extension
documentation</jump> for a description of using extensions in a stylesheet.
Please note that the W3C XSL Working Group is working on a specification for
standard extension bindings, and this module will change to follow that
specification. </p><p>[More needed... -sb]</p></s3></s2><anchor name="xpath"/>
<s2 title="XPath Module">
- <p><link idref="xpath">XPath Module</link></p>
+ <p><link>XPath Module</link></p>
<p>This module is pulled out of the Xalan package, and put in the
org.apache package, to emphasize that the intention is that this package can be
used independently of the XSLT engine, even though it has dependencies on the
Xalan utils module.</p><p><img src="org_apache.gif" alt="xalan --->
xpath"/></p>
<p>The XPath module first compiles the XPath strings into expression
trees, and then executes these expressions via a call to the XPath execute(...)
function. </p> <p>Major classes
are:</p><gloss><label>XPath</label><item>Represents a compiled XPath. Major
function is <code>XObject execute(XPathContext xctxt, Node contextNode,
PrefixResolver
namespaceContext).</code></item></gloss><gloss><label>XPathAPI</label><item>The
methods in this class are convenience methods into the
low-level XPath
API.</item></gloss><gloss><label>XPathContext</label><item>Used as the runtime
execution context for
XPath.</item></gloss><gloss><label>DOMHelper</label><item>Used as a helper for
handling DOM issues. May be subclassed to take advantage
of specific DOM
implementations.</item></gloss><gloss><label>SourceTreeManager</label><item>bottlenecks
all management of source trees. The methods
in this class should allow easy garbage collection of source
- trees, and should centralize parsing for those source
trees.</item></gloss><gloss><label>Expression</label><item>The base-class of
all expression objects, allowing polymorphic behaviors.</item></gloss><p>The
general architecture of the XPath module is divided into the compiler, and
categories of expression objects.</p><p><img src="xpath.gif" alt="xpath
modules"/></p><p>The most important module is the axes module. This module
implements the DOM2 <link
anchor="http://www.w3.org/TR/DOM-Level-2/traversal.html#Iterator-overview";>NodeIterator</link>
interface, and is meant to allow XPath clients to either override the default
behavior or to replace this behavior.</p><p>The LocPathIterator and
UnionPathIterator classes implement the <link
anchor="http://www.w3.org/TR/DOM-Level-2/java-binding.html#org.w3c.dom.traversal.NodeIterator";>NodeIterator</link>
interface, and polymorphically use AxesWalker derived objects to execute each
step in the path. The whole trick is to execute the LocationPath in
depth-first d
ocument order so that nodes can be found without necessarily looking ahead or
performing a breadth-first search.</p><s3 title="XPath Database
Connection"><p><link idref="xpath-database">XPath Direct Database
Connections</link></p><p>An important part of the XPath design in both Xalan 1
and Xalan 2, is to enable database connections to be used as drivers directly
to the XPath <link
anchor="http://www.w3.org/TR/xpath#location-paths";>LocationPath</link>
handling. This allows databases to be directly connected to the transform, and
be able to take advantage of internal indexing and the like. While in Xalan 1
this was done via the <link
anchor="http://xml.apache.org/xalan/apidocs/org/apache/xalan/xpath/XLocator.html";>XLocator</link>
interface, in Xalan 2 this interface is no longer used, and has been replaced
by the DOM2 <link
anchor="http://www.w3.org/TR/DOM-Level-2/traversal.html#Iterator-overview";>NodeIterator</link>
interface. An application or extension should be able to install their own
NodeIterator for
a given document.</p><p><img src="data.gif" alt="data.gif"/></p><p>[More to
do]</p></s3></s2>
+ trees, and should centralize parsing for those source
trees.</item></gloss><gloss><label>Expression</label><item>The base-class of
all expression objects, allowing polymorphic behaviors.</item></gloss><p>The
general architecture of the XPath module is divided into the compiler, and
categories of expression objects.</p><p><img src="xpath.gif" alt="xpath
modules"/></p><p>The most important module is the axes module. This module
implements the DOM2 <jump
href="http://www.w3.org/TR/DOM-Level-2/traversal.html#Iterator-overview";>NodeIterator</jump>
interface, and is meant to allow XPath clients to either override the default
behavior or to replace this behavior.</p><p>The LocPathIterator and
UnionPathIterator classes implement the <jump
href="http://www.w3.org/TR/DOM-Level-2/java-binding.html#org.w3c.dom.traversal.NodeIterator";>NodeIterator</jump>
interface, and polymorphically use AxesWalker derived objects to execute each
step in the path. The whole trick is to execute the LocationPath in
depth-first docum
ent order so that nodes can be found without necessarily looking ahead or
performing a breadth-first search.</p><anchor name="xpathdbconn"/><s3
title="XPath Database Connection"><p><link>XPath Direct Database
Connections</link></p><p>An important part of the XPath design in both Xalan 1
and Xalan 2, is to enable database connections to be used as drivers directly
to the XPath <jump
href="http://www.w3.org/TR/xpath#location-paths";>LocationPath</jump> handling.
This allows databases to be directly connected to the transform, and be able to
take advantage of internal indexing and the like. While in Xalan 1 this was
done via the <jump
href="http://xml.apache.org/xalan/apidocs/org/apache/xalan/xpath/XLocator.html";>XLocator</jump>
interface, in Xalan 2 this interface is no longer used, and has been replaced
by the DOM2 <jump
href="http://www.w3.org/TR/DOM-Level-2/traversal.html#Iterator-overview";>NodeIterator</jump>
interface. An application or extension should be able to install their own
NodeIterator for a gi
ven document.</p><p><img src="data.gif" alt="data.gif"/></p><p>[More to
do]</p></s3></s2><anchor name="utils"/>
<s2 title="Utils Package">
- <p><link idref="utils">Utils Package</link></p>
+ <p><link>Utils Package</link></p>
<p>This package contains general utilities for use by both the xalan and
xpath packages. It is the intention that many of these utility classes (or
their equivalents) be eventually brought into the org.apache.xml package for
general use. The list of major utilities are as
follows:</p><gloss><label>AttList</label><item>Wraps a DOM attribute list in a
SAX Attributes.</item></gloss><gloss><label>BoolStack, IntStack, IntVector,
etc.</label><item>Simple stacks and vectors for primitive
values.</item></gloss><gloss><label>DefaultErrorHandler</label><item>Implements
SAX error handler for default
reporting.</item></gloss><gloss><label>DOMBuilder</label><item>Takes SAX events
(in addition to some extra events
that SAX doesn't handle yet) and adds the result to a document
or document fragment.</item></gloss><gloss><label>Heap</label><item>Classic
heap
implementation.</item></gloss><gloss><label>MutableAttrListImpl</label><item>Mutable
version of
AttributesImpl.</item></gloss><gloss><label>NameSpace</label><item>A
representation of a
namespace.</item></gloss><gloss><label>NodeVector</label><item>A very simple
table that stores a list of
Nodes.</item></gloss><gloss><label>ObjectPool</label><item>Used for reuse of
objects.</item></gloss><gloss><label>PrefixResolver</label><item>The class that
implements this interface can resolve prefixes
to
namespaces.</item></gloss><gloss><label>PrefixResolverDefault</label><item>This
class implements a generic PrefixResolver for a DOM, that
can be used to perform prefix-to-namespace lookup
- for an XPath.</item></gloss><gloss><label>QName</label><item>Class to
represent a qualified XML
name.</item></gloss><gloss><label>StringToStringTable</label><item>A very
simple lookup table that stores a list of strings for lookup. Used when a
hashtable is too much
overhead.</item></gloss><gloss><label>SystemIDResolver</label><item>Able to
take a SystemID string and try and turn it into a good absolute
URL.</item></gloss><gloss><label>TreeWalker</label><item>Implements a Visitor
design pattern, doing a pre-order walk of the DOM tree, calling a
ContentHandler interface as it goes. Used for DOM-to-SAX
conversion.</item></gloss><gloss><label>Trie</label><item>A digital search trie
for 7-bit ASCII text.</item></gloss><gloss><label>UnImplNode</label><item>To be
subclassed by classes that wish to act as DOM nodes, without having to
implement all the methods. Widely used.</item></gloss></s2>
+ for an XPath.</item></gloss><gloss><label>QName</label><item>Class to
represent a qualified XML
name.</item></gloss><gloss><label>StringToStringTable</label><item>A very
simple lookup table that stores a list of strings for lookup. Used when a
hashtable is too much
overhead.</item></gloss><gloss><label>SystemIDResolver</label><item>Able to
take a SystemID string and try and turn it into a good absolute
URL.</item></gloss><gloss><label>TreeWalker</label><item>Implements a Visitor
design pattern, doing a pre-order walk of the DOM tree, calling a
ContentHandler interface as it goes. Used for DOM-to-SAX
conversion.</item></gloss><gloss><label>Trie</label><item>A digital search trie
for 7-bit ASCII text.</item></gloss><gloss><label>UnImplNode</label><item>To be
subclassed by classes that wish to act as DOM nodes, without having to
implement all the methods. Widely used.</item></gloss></s2><anchor
name="other"/>
<s2 title="Other Packages">
- <p><link idref="other">Other Packages</link></p>
+ <p><link>Other Packages</link></p>
<gloss><label>client</label><item>Implementation of Xalan Applet
[should we keep this?].
</item></gloss>
<gloss><label>dtm</label><item>Implementation of the Document
Table Model (DTM) [Should we keep this?].</item></gloss>
<gloss><label>extensions</label><item>Implementation of Xalan
Extension Mechanism, which uses the Bean Scripting Framework.</item></gloss>
- <gloss><label>lib</label><item>Implementation of Xalan-specific
extensions [I want to add lots more extensions to this
package!].</item></gloss><gloss><label>res</label><item>Contains strings that
require internationalization.</item></gloss></s2>
+ <gloss><label>lib</label><item>Implementation of Xalan-specific
extensions [I want to add lots more extensions to this
package!].</item></gloss><gloss><label>res</label><item>Contains strings that
require internationalization.</item></gloss></s2><anchor name="coding"/>
<s2 title="Coding Conventions">
- <p><link idref="coding-conventions">Coding Conventions</link></p>
+ <p><link>Coding Conventions</link></p>
<p>This section documents the coding conventions used in the Xalan
source.</p>
<ol>
@@ -489,9 +503,9 @@
<li>Package-scoped member variables, public member variables,
and
protected member variables should not be declared.</li>
</ol>
- </s2>
+ </s2><anchor name="open"/>
<s2 title="Open Issues">
- <p><link idref="open-issues">Open Issues</link></p>
+ <p><link>Open Issues</link></p>
<p>This section documents architectural and design issues that I still
consider to be open or unsolved. (This list is ongoing, and
will change over
time... it's simply a place for me to note problems that are
ongoing and need
