1 /*
2 * Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26 package javax.xml.transform;
27
28 import java.util.Properties;
29
30 /**
31 * An instance of this abstract class can transform a
32 * source tree into a result tree.
33 *
34 * <p>An instance of this class can be obtained with the
35 * {@link TransformerFactory#newTransformer TransformerFactory.newTransformer}
36 * method. This instance may then be used to process XML from a
37 * variety of sources and write the transformation output to a
38 * variety of sinks.</p>
39 *
40 * <p>An object of this class may not be used in multiple threads
41 * running concurrently. Different Transformers may be used
42 * concurrently by different threads.</p>
43 *
44 * <p>A <code>Transformer</code> may be used multiple times. Parameters and
45 * output properties are preserved across transformations.</p>
46 *
47 * @author <a href="Jeff.Suttor@Sun.com">Jeff Suttor</a>
48 * @since 1.4
49 */
50 public abstract class Transformer {
51
52 /**
53 * Default constructor is protected on purpose.
54 */
55 protected Transformer() { }
56
57 /**
58 * <p>Reset this <code>Transformer</code> to its original configuration.</p>
59 *
60 * <p><code>Transformer</code> is reset to the same state as when it was created with
61 * {@link TransformerFactory#newTransformer()},
62 * {@link TransformerFactory#newTransformer(Source source)} or
63 * {@link Templates#newTransformer()}.
64 * <code>reset()</code> is designed to allow the reuse of existing <code>Transformer</code>s
65 * thus saving resources associated with the creation of new <code>Transformer</code>s.</p>
66 *
67 * <p>The reset <code>Transformer</code> is not guaranteed to have the same {@link URIResolver}
68 * or {@link ErrorListener} <code>Object</code>s, e.g. {@link Object#equals(Object obj)}.
69 * It is guaranteed to have a functionally equal <code>URIResolver</code>
70 * and <code>ErrorListener</code>.</p>
71 *
72 * @throws UnsupportedOperationException When implementation does not
73 * override this method.
74 *
75 * @since 1.5
76 */
77 public void reset() {
78
79 // implementors should override this method
80 throw new UnsupportedOperationException(
81 "This Transformer, \"" + this.getClass().getName() + "\", does not support the reset functionality."
82 + " Specification \"" + this.getClass().getPackage().getSpecificationTitle() + "\""
83 + " version \"" + this.getClass().getPackage().getSpecificationVersion() + "\""
84 );
85 }
86
87 /**
88 * <p>Transform the XML <code>Source</code> to a <code>Result</code>.
89 * Specific transformation behavior is determined by the settings of the
90 * <code>TransformerFactory</code> in effect when the
91 * <code>Transformer</code> was instantiated and any modifications made to
92 * the <code>Transformer</code> instance.</p>
93 *
94 * <p>An empty <code>Source</code> is represented as an empty document
95 * as constructed by {@link javax.xml.parsers.DocumentBuilder#newDocument()}.
96 * The result of transforming an empty <code>Source</code> depends on
97 * the transformation behavior; it is not always an empty
98 * <code>Result</code>.</p>
99 *
100 * @param xmlSource The XML input to transform.
101 * @param outputTarget The <code>Result</code> of transforming the
102 * <code>xmlSource</code>.
103 *
104 * @throws TransformerException If an unrecoverable error occurs
105 * during the course of the transformation.
106 */
107 public abstract void transform(Source xmlSource, Result outputTarget)
108 throws TransformerException;
109
110 /**
111 * Add a parameter for the transformation.
112 *
113 * <p>Pass a qualified name as a two-part string, the namespace URI
114 * enclosed in curly braces ({}), followed by the local name. If the
115 * name has a null URL, the String only contain the local name. An
116 * application can safely check for a non-null URI by testing to see if the
117 * first character of the name is a '{' character.</p>
118 * <p>For example, if a URI and local name were obtained from an element
119 * defined with <xyz:foo
120 * xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>,
121 * then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo".
122 * Note that no prefix is used.</p>
123 *
124 * @param name The name of the parameter, which may begin with a
125 * namespace URI in curly braces ({}).
126 * @param value The value object. This can be any valid Java object. It is
127 * up to the processor to provide the proper object coersion or to simply
128 * pass the object on for use in an extension.
129 *
130 * @throws NullPointerException If value is null.
131 */
132 public abstract void setParameter(String name, Object value);
133
134 /**
135 * Get a parameter that was explicitly set with setParameter.
136 *
137 * <p>This method does not return a default parameter value, which
138 * cannot be determined until the node context is evaluated during
139 * the transformation process.
140 *
141 * @param name of <code>Object</code> to get
142 *
143 * @return A parameter that has been set with setParameter.
144 */
145 public abstract Object getParameter(String name);
146
147 /**
148 * <p>Set a list of parameters.</p>
149 *
150 * <p>Note that the list of parameters is specified as a
151 * <code>Properties</code> <code>Object</code> which limits the parameter
152 * values to <code>String</code>s. Multiple calls to
153 * {@link #setParameter(String name, Object value)} should be used when the
154 * desired values are non-<code>String</code> <code>Object</code>s.
155 * The parameter names should conform as specified in
156 * {@link #setParameter(String name, Object value)}.
157 * An <code>IllegalArgumentException</code> is thrown if any names do not
158 * conform.</p>
159 *
160 * <p>New parameters in the list are added to any existing parameters.
161 * If the name of a new parameter is equal to the name of an existing
162 * parameter as determined by {@link java.lang.Object#equals(Object obj)},
163 * the existing parameter is set to the new value.</p>
164 *
165 * @param params Parameters to set.
166 *
167 * @throws IllegalArgumentException If any parameter names do not conform
168 * to the naming rules.
169 */
170
171 /**
172 * Clear all parameters set with setParameter.
173 */
174 public abstract void clearParameters();
175
176 /**
177 * Set an object that will be used to resolve URIs used in
178 * document().
179 *
180 * <p>If the resolver argument is null, the URIResolver value will
181 * be cleared and the transformer will no longer have a resolver.</p>
182 *
183 * @param resolver An object that implements the URIResolver interface,
184 * or null.
185 */
186 public abstract void setURIResolver(URIResolver resolver);
187
188 /**
189 * Get an object that will be used to resolve URIs used in
190 * document().
191 *
192 * @return An object that implements the URIResolver interface,
193 * or null.
194 */
195 public abstract URIResolver getURIResolver();
196
197 /**
198 * Set the output properties for the transformation. These
199 * properties will override properties set in the Templates
200 * with xsl:output.
201 *
202 * <p>If argument to this function is null, any properties
203 * previously set are removed, and the value will revert to the value
204 * defined in the templates object.</p>
205 *
206 * <p>Pass a qualified property key name as a two-part string, the namespace
207 * URI enclosed in curly braces ({}), followed by the local name. If the
208 * name has a null URL, the String only contain the local name. An
209 * application can safely check for a non-null URI by testing to see if the
210 * first character of the name is a '{' character.</p>
211 * <p>For example, if a URI and local name were obtained from an element
212 * defined with <xyz:foo
213 * xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>,
214 * then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo".
215 * Note that no prefix is used.</p>
216 * An <code>IllegalArgumentException</code> is thrown if any of the
217 * argument keys are not recognized and are not namespace qualified.
218 *
219 * @param oformat A set of output properties that will be
220 * used to override any of the same properties in affect
221 * for the transformation.
222 *
223 * @throws IllegalArgumentException When keys are not recognized and
224 * are not namespace qualified.
225 *
226 * @see javax.xml.transform.OutputKeys
227 * @see java.util.Properties
228 *
229 */
230 public abstract void setOutputProperties(Properties oformat);
231
232 /**
233 * <p>Get a copy of the output properties for the transformation.</p>
234 *
235 * <p>The properties returned should contain properties set by the user,
236 * and properties set by the stylesheet, and these properties
237 * are "defaulted" by default properties specified by
238 * <a href="http://www.w3.org/TR/xslt#output">section 16 of the
239 * XSL Transformations (XSLT) W3C Recommendation</a>. The properties that
240 * were specifically set by the user or the stylesheet should be in the base
241 * Properties list, while the XSLT default properties that were not
242 * specifically set should be the default Properties list. Thus,
243 * getOutputProperties().getProperty(String key) will obtain any
244 * property in that was set by {@link #setOutputProperty},
245 * {@link #setOutputProperties}, in the stylesheet, <em>or</em> the default
246 * properties, while
247 * getOutputProperties().get(String key) will only retrieve properties
248 * that were explicitly set by {@link #setOutputProperty},
249 * {@link #setOutputProperties}, or in the stylesheet.</p>
250 *
251 * <p>Note that mutation of the Properties object returned will not
252 * effect the properties that the transformer contains.</p>
253 *
254 * <p>If any of the argument keys are not recognized and are not
255 * namespace qualified, the property will be ignored and not returned.
256 * In other words the behaviour is not orthogonal with
257 * {@link #setOutputProperties setOutputProperties}.</p>
258 *
259 * @return A copy of the set of output properties in effect for
260 * the next transformation.
261 *
262 * @see javax.xml.transform.OutputKeys
263 * @see java.util.Properties
264 * @see <a href="http://www.w3.org/TR/xslt#output">
265 * XSL Transformations (XSLT) Version 1.0</a>
266 */
267 public abstract Properties getOutputProperties();
268
269 /**
270 * Set an output property that will be in effect for the
271 * transformation.
272 *
273 * <p>Pass a qualified property name as a two-part string, the namespace URI
274 * enclosed in curly braces ({}), followed by the local name. If the
275 * name has a null URL, the String only contain the local name. An
276 * application can safely check for a non-null URI by testing to see if the
277 * first character of the name is a '{' character.</p>
278 * <p>For example, if a URI and local name were obtained from an element
279 * defined with <xyz:foo
280 * xmlns:xyz="http://xyz.foo.com/yada/baz.html"/>,
281 * then the qualified name would be "{http://xyz.foo.com/yada/baz.html}foo".
282 * Note that no prefix is used.</p>
283 *
284 * <p>The Properties object that was passed to {@link #setOutputProperties}
285 * won't be effected by calling this method.</p>
286 *
287 * @param name A non-null String that specifies an output
288 * property name, which may be namespace qualified.
289 * @param value The non-null string value of the output property.
290 *
291 * @throws IllegalArgumentException If the property is not supported, and is
292 * not qualified with a namespace.
293 *
294 * @see javax.xml.transform.OutputKeys
295 */
296 public abstract void setOutputProperty(String name, String value)
297 throws IllegalArgumentException;
298
299 /**
300 * <p>Get an output property that is in effect for the transformer.</p>
301 *
302 * <p>If a property has been set using {@link #setOutputProperty},
303 * that value will be returned. Otherwise, if a property is explicitly
304 * specified in the stylesheet, that value will be returned. If
305 * the value of the property has been defaulted, that is, if no
306 * value has been set explicitly either with {@link #setOutputProperty} or
307 * in the stylesheet, the result may vary depending on
308 * implementation and input stylesheet.</p>
309 *
310 * @param name A non-null String that specifies an output
311 * property name, which may be namespace qualified.
312 *
313 * @return The string value of the output property, or null
314 * if no property was found.
315 *
316 * @throws IllegalArgumentException If the property is not supported.
317 *
318 * @see javax.xml.transform.OutputKeys
319 */
320 public abstract String getOutputProperty(String name)
321 throws IllegalArgumentException;
322
323 /**
324 * Set the error event listener in effect for the transformation.
325 *
326 * @param listener The new error listener.
327 *
328 * @throws IllegalArgumentException if listener is null.
329 */
330 public abstract void setErrorListener(ErrorListener listener)
331 throws IllegalArgumentException;
332
333 /**
334 * Get the error event handler in effect for the transformation.
335 * Implementations must provide a default error listener.
336 *
337 * @return The current error handler, which should never be null.
338 */
339 public abstract ErrorListener getErrorListener();
340 }