/
niceSOFT
/
openjdk21
Обзор
Документация
Войти
/
niceSOFT
/
openjdk21
Код
Задачи
Вики
Пакеты
0
Релизы
0
Аналитика
Безопасность
master
src/java.xml/share/classes/javax/xml/transform/overview.html
291 строка
10 KB
Magnus Ihse Bursie
8285485: Fix typos in corelibs
17 май 2022, 15:10
17 май 2022, 15:10
e68024c
Код
Авторство
О чём код?
<?xml version="1.0" encoding="UTF-8"?> <!-- Copyright (c) 2000, 2022, 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. --> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <title>Transformation API For XML</title> <meta name="CVS" content="$Id: overview.html,v 1.2 2005/06/10 03:50:39 jeffsuttor Exp $" /> <meta name="AUTHOR" content="Jeff Suttor" /> </head> <body> <h2>Transformation API For XML</h2> <h3>Introduction</h3> <p>This overview describes the set of APIs contained in javax.xml.transform. For the sake of brevity, these interfaces are referred to as TrAX (Transformations for XML). </p> <p>There is a broad need for Java applications to be able to transform XML and related tree-shaped data structures. In fact, XML is not normally very useful to an application without going through some sort of transformation, unless the semantic structure is used directly as data. Almost all XML-related applications need to perform transformations. Transformations may be described by Java code, Perl code, <A href="http://www.w3.org/TR/xslt">XSLT</A> Stylesheets, other types of script, or by proprietary formats. The inputs, one or multiple, to a transformation, may be a URL, XML stream, a DOM tree, SAX Events, or a proprietary format or data structure. The output types are the pretty much the same types as the inputs, but different inputs may need to be combined with different outputs.</p> <p>The great challenge of a transformation API is how to deal with all the possible combinations of inputs and outputs, without becoming specialized for any of the given types.</p> <p>The Java community will greatly benefit from a common API that will allow them to understand and apply a single model, write to consistent interfaces, and apply the transformations polymorphically. TrAX attempts to define a model that is clean and generic, yet fills general application requirements across a wide variety of uses. </p> <h3>General Terminology</h3> <p>This section will explain some general terminology used in this document. Technical terminology will be explained in the Model section. In many cases, the general terminology overlaps with the technical terminology.</p> <ul> <li> <p> <b>Tree</b> <br>This term, as used within this document, describes an abstract structure that consists of nodes or events that may be produced by XML. A Tree physically may be a DOM tree, a series of well balanced parse events (such as those coming from a SAX2 ContentHander), a series of requests (the result of which can describe a tree), or a stream of marked-up characters.</p> </li> <li> <p> <b>Source Tree(s)</b> <br>One or more trees that are the inputs to the transformation.</p> </li> <li> <p> <b>Result Tree(s)</b> <br>One or more trees that are the output of the transformation.</p> </li> <li> <p> <b>Transformation</b> <br>The processor of consuming a stream or tree to produce another stream or tree.</p> </li> <li> <p> <b>Identity (or Copy) Transformation</b> <br>The process of transformation from a source to a result, making as few structural changes as possible and no informational changes. The term is somewhat loosely used, as the process is really a copy. from one "format" (such as a DOM tree, stream, or set of SAX events) to another.</p> </li> <li> <p> <b>Serialization</b> <br>The process of taking a tree and turning it into a stream. In some sense, a serialization is a specialized transformation.</p> </li> <li> <p> <b>Parsing</b> <br>The process of taking a stream and turning it into a tree. In some sense, parsing is a specialized transformation.</p> </li> <li> <p> <b>Transformer</b> <br>A Transformer is the object that executes the transformation. </p> </li> <li> <p> <b>Transformation instructions</b> <br>Describes the transformation. A form of code, script, or simply a declaration or series of declarations.</p> </li> <li> <p> <b>Stylesheet</b> <br>The same as "transformation instructions," except it is likely to be used in conjunction with <A href="http://www.w3.org/TR/xslt">XSLT</A>.</p> </li> <li> <p> <b>Templates</b> <br>Another form of "transformation instructions." In the TrAX interface, this term is used to describe processed or compiled transformation instructions. The Source flows through a Templates object to be formed into the Result.</p> </li> <li> <p> <b>Processor</b> <br>A general term for the thing that may both process the transformation instructions, and perform the transformation.</p> </li> <li> <p> <b>DOM</b> <br>Document Object Model, specifically referring to the <A href="#http://www.w3.org/TR/DOM-Level-2%20">Document Object Model (DOM) Level 2 Specification</A>.</p> </li> <li> <p> <b>SAX</b><br> Simple API for XML, specifically referring to the <a href="http://sax.sourceforge.net/">SAX 2.0.2 release</a>. </p> </li> </ul> <h3>Model</h3> <p>The section defines the abstract model for TrAX, apart from the details of the interfaces.</p> <p>A TRaX <A href="#pattern-TransformerFactory">TransformerFactory</A> is an object that processes transformation instructions, and produces <A href="#pattern-Templates">Templates</A> (in the technical terminology). A <A href="#pattern-Templates">Templates</A> object provides a <A href="#pattern-Transformer">Transformer</A>, which transforms one or more <A href="#pattern-Source">Source</A>s into one or more <A href="#pattern-Result">Result</A>s.</p> <p>To use the TRaX interface, you create a <A href="#pattern-TransformerFactory">TransformerFactory</A>, which may directly provide a <A href="#pattern-Transformers">Transformers</A>, or which can provide <A href="#pattern-Templates">Templates</A> from a variety of <A href="#pattern-Source">Source</A>s. The <A href="#pattern-Templates">Templates</A> object is a processed or compiled representation of the transformation instructions, and provides a <A href="#pattern-Transformer">Transformer</A>. The <A href="#pattern-Transformer">Transformer</A> processes a <A href="#pattern-Transformer">Source</A> according to the instructions found in the <A href="#pattern-Templates">Templates</A>, and produces a <A href="#pattern-Result">Result</A>.</p> <p>The process of transformation from a tree, either in the form of an object model, or in the form of parse events, into a stream, is known as <code>serialization</code>. We believe this is the most suitable term for this process, despite the overlap with Java object serialization.</p> <H3>TRaX Patterns</H3> <ul> <p> <b><a name="pattern-Processor">Processor</a></b> <br> <br> <i>Intent: </i>Generic concept for the set of objects that implement the TrAX interfaces.<br> <i>Responsibilities: </i>Create compiled transformation instructions, transform sources, and manage transformation parameters and properties.<br> <i>Thread safety: </i>Only the Templates object can be used concurrently in multiple threads. The rest of the processor does not do synchronized blocking, and so may not be used to perform multiple concurrent operations. Different Processors can be used concurrently by different threads.</p> <p> <b><a name="pattern-TransformerFactory">TransformerFactory</a></b> <br> <br> <i>Intent: </i>Serve as a vendor-neutral Processor interface for <A href="http://www.w3.org/TR/xslt">XSLT</A> and similar processors.<br> <i>Responsibilities: </i>Serve as a factory for a concrete implementation of an TransformerFactory, serve as a direct factory for Transformer objects, serve as a factory for Templates objects, and manage processor specific features.<br> <i>Thread safety: </i>A TransformerFactory may not perform multiple concurrent operations.</p> <p> <b><a name="pattern-Templates">Templates</a></b> <br> <br> <i>Intent: </i>The runtime representation of the transformation instructions.<br> <i>Responsibilities: </i>A data bag for transformation instructions; act as a factory for Transformers.<br> <i>Thread safety: </i>Threadsafe for concurrent usage over multiple threads once construction is complete.</p> <p> <b><a name="pattern-Transformer">Transformer</a></b> <br> <br> <i>Intent: </i>Act as a per-thread execution context for transformations, act as an interface for performing the transformation.<br> <i>Responsibilities: </i>Perform the transformation.<br> <i>Thread safety: </i>Only one instance per thread is safe.<br> <i>Notes: </i>The Transformer is bound to the Templates object that created it.</p> <p> <b><a name="pattern-Source">Source</a></b> <br> <br> <i>Intent: </i>Serve as a single vendor-neutral object for multiple types of input.<br> <i>Responsibilities: </i>Act as simple data holder for System IDs, DOM nodes, streams, etc.<br> <i>Thread safety: </i>Threadsafe concurrently over multiple threads for read-only operations; must be synchronized for edit operations.</p> <p> <b><a name="pattern-Result">Result</a></b> <br> <br> <i>Potential alternate name: </i>ResultTarget<br> <i>Intent: </i>Serve as a single object for multiple types of output, so there can be simple process method signatures.<br> <i>Responsibilities: </i>Act as simple data holder for output stream, DOM node, ContentHandler, etc.<br> <i>Thread safety: </i>Threadsafe concurrently over multiple threads for read-only, must be synchronized for edit.</p> </ul> </body> </html>