Mercurial > hg > openjdk > jdk9 > jaxp
view src/java.xml/share/classes/javax/xml/transform/package-info.java @ 1133:a208fa9beeee
8180349: Review JAXP Java SE 9 API javadocs
Reviewed-by: rriggs, lancea
author | joehw |
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date | Wed, 24 May 2017 14:10:04 -0700 |
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/* * Copyright (c) 2015, 2017, 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. */ /** * Defines the generic APIs for processing transformation instructions, * and performing a transformation from source to result. These interfaces have no * dependencies on SAX or the DOM standard, and try to make as few assumptions as * possible about the details of the source and result of a transformation. It * achieves this by defining {@link javax.xml.transform.Source} and * {@link javax.xml.transform.Result} interfaces. * * <p> * To provide concrete classes for the user, the API defines specializations * of the interfaces found at the root level. These interfaces are found in * {@link javax.xml.transform.sax}, {@link javax.xml.transform.dom}, * {@link javax.xml.transform.stax}, and {@link javax.xml.transform.stream}. * * * <h3>Creating Objects</h3> * * <p> * The API allows a concrete {@link javax.xml.transform.TransformerFactory} * object to be created from the static function * {@link javax.xml.transform.TransformerFactory#newInstance}. * * * <h3>Specification of Inputs and Outputs</h3> * * <p> * This API defines two interface objects called {@link javax.xml.transform.Source} * and {@link javax.xml.transform.Result}. In order to pass Source and Result * objects to the interfaces, concrete classes must be used. The following concrete * representations are defined for each of these objects: * {@link javax.xml.transform.stream.StreamSource} and * {@link javax.xml.transform.stream.StreamResult}, * {@link javax.xml.transform.stax.StAXSource} and * {@link javax.xml.transform.stax.StAXResult}, and * {@link javax.xml.transform.sax.SAXSource} and * {@link javax.xml.transform.sax.SAXResult}, and * {@link javax.xml.transform.dom.DOMSource} and * {@link javax.xml.transform.dom.DOMResult}. Each of these objects defines a * FEATURE string (which is in the form of a URL), which can be passed into * {@link javax.xml.transform.TransformerFactory#getFeature} to see if the given * type of Source or Result object is supported. For instance, to test if a * DOMSource and a StreamResult is supported, you can apply the following test. * * <pre> * <code> * TransformerFactory tfactory = TransformerFactory.newInstance(); * if (tfactory.getFeature(DOMSource.FEATURE) && * tfactory.getFeature(StreamResult.FEATURE)) { * ... * } * </code> * </pre> * * * <h3> * <a id="qname-delimiter">Qualified Name Representation</a> * </h3> * * <p> * <a href="http://www.w3.org/TR/REC-xml-names">Namespaces</a> present something * of a problem area when dealing with XML objects. Qualified Names appear in XML * markup as prefixed names. But the prefixes themselves do not hold identity. * Rather, it is the URIs that they contextually map to that hold the identity. * Therefore, when passing a Qualified Name like "xyz:foo" among Java programs, * one must provide a means to map "xyz" to a namespace. * * <p> * One solution has been to create a "QName" object that holds the namespace URI, * as well as the prefix and local name, but this is not always an optimal solution, * as when, for example, you want to use unique strings as keys in a dictionary * object. Not having a string representation also makes it difficult to specify * a namespaced identity outside the context of an XML document. * * <p> * In order to pass namespaced values to transformations, for instance when setting * a property or a parameter on a {@link javax.xml.transform.Transformer} object, * this specification defines that a String "qname" object parameter be passed as * two-part string, the namespace URI enclosed in curly braces ({}), followed by * the local name. If the qname has a null URI, then the String object only * contains the local name. An application can safely check for a non-null URI by * testing to see if the first character of the name is a '{' character. * * <p> * For example, if a URI and local name were obtained from an element defined with * <xyz:foo xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>, then the * Qualified Name would be "{http://xyz.foo.com/yada/baz.html}foo". Note that the * prefix is lost. * * * <h3>Result Tree Serialization</h3> * * <p> * Serialization of the result tree to a stream can be controlled with the * {@link javax.xml.transform.Transformer#setOutputProperties} and the * {@link javax.xml.transform.Transformer#setOutputProperty} methods. * These properties only apply to stream results, they have no effect when * the result is a DOM tree or SAX event stream. * * <p> * Strings that match the <a href="http://www.w3.org/TR/xslt#output">XSLT * specification for xsl:output attributes</a> can be referenced from the * {@link javax.xml.transform.OutputKeys} class. Other strings can be * specified as well. * If the transformer does not recognize an output key, a * {@link java.lang.IllegalArgumentException} is thrown, unless the key name * is <a href="#qname-delimiter">namespace qualified</a>. Output key names * that are namespace qualified are always allowed, although they may be * ignored by some implementations. * * <p> * If all that is desired is the simple identity transformation of a * source to a result, then {@link javax.xml.transform.TransformerFactory} * provides a * {@link javax.xml.transform.TransformerFactory#newTransformer()} method * with no arguments. This method creates a Transformer that effectively copies * the source to the result. This method may be used to create a DOM from SAX * events or to create an XML or HTML stream from a DOM or SAX events. * * <h3>Exceptions and Error Reporting</h3> * * <p> * The transformation API throw three types of specialized exceptions. A * {@link javax.xml.transform.TransformerFactoryConfigurationError} is parallel to * the {@link javax.xml.parsers.FactoryConfigurationError}, and is thrown * when a configuration problem with the TransformerFactory exists. This error * will typically be thrown when the transformation factory class specified with * the "javax.xml.transform.TransformerFactory" system property cannot be found or * instantiated. * * <p> * A {@link javax.xml.transform.TransformerConfigurationException} * may be thrown if for any reason a Transformer can not be created. A * TransformerConfigurationException may be thrown if there is a syntax error in * the transformation instructions, for example when * {@link javax.xml.transform.TransformerFactory#newTransformer} is * called. * * <p> * {@link javax.xml.transform.TransformerException} is a general * exception that occurs during the course of a transformation. A transformer * exception may wrap another exception, and if any of the * {@link javax.xml.transform.TransformerException#printStackTrace()} * methods are called on it, it will produce a list of stack dumps, starting from * the most recent. The transformer exception also provides a * {@link javax.xml.transform.SourceLocator} object which indicates where * in the source tree or transformation instructions the error occurred. * {@link javax.xml.transform.TransformerException#getMessageAndLocation()} * may be called to get an error message with location info, and * {@link javax.xml.transform.TransformerException#getLocationAsString()} * may be called to get just the location string. * * <p> * Transformation warnings and errors are sent to an * {@link javax.xml.transform.ErrorListener}, at which point the application may * decide to report the error or warning, and may decide to throw an * <code>Exception</code> for a non-fatal error. The <code>ErrorListener</code> * may be set via {@link javax.xml.transform.TransformerFactory#setErrorListener} * for reporting errors that have to do with syntax errors in the transformation * instructions, or via {@link javax.xml.transform.Transformer#setErrorListener} * to report errors that occur during the transformation. The <code>ErrorListener</code> * on both objects will always be valid and non-<code>null</code>, whether set by * the application or a default implementation provided by the processor. * The default implementation provided by the processor will report all warnings * and errors to <code>System.err</code> and does not throw any <code>Exception</code>s. * Applications are <em>strongly</em> encouraged to register and use * <code>ErrorListener</code>s that insure proper behavior for warnings and * errors. * * * <h3>Resolution of URIs within a transformation</h3> * * <p> * The API provides a way for URIs referenced from within the stylesheet * instructions or within the transformation to be resolved by the calling * application. This can be done by creating a class that implements the * {@link javax.xml.transform.URIResolver} interface, with its one method, * {@link javax.xml.transform.URIResolver#resolve}, and use this class to * set the URI resolution for the transformation instructions or transformation * with {@link javax.xml.transform.TransformerFactory#setURIResolver} or * {@link javax.xml.transform.Transformer#setURIResolver}. The * <code>URIResolver.resolve</code> method takes two String arguments, the URI * found in the stylesheet instructions or built as part of the transformation * process, and the base URI against which the first argument will be made absolute * if the absolute URI is required. * The returned {@link javax.xml.transform.Source} object must be usable by * the transformer, as specified in its implemented features. * * @since 1.5 */ package javax.xml.transform;