| /* XPathFactory.java -- |
| Copyright (C) 2004, 2005 Free Software Foundation, Inc. |
| |
| This file is part of GNU Classpath. |
| |
| GNU Classpath is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| GNU Classpath 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 for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with GNU Classpath; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 USA. |
| |
| Linking this library statically or dynamically with other modules is |
| making a combined work based on this library. Thus, the terms and |
| conditions of the GNU General Public License cover the whole |
| combination. |
| |
| As a special exception, the copyright holders of this library give you |
| permission to link this library with independent modules to produce an |
| executable, regardless of the license terms of these independent |
| modules, and to copy and distribute the resulting executable under |
| terms of your choice, provided that you also meet, for each linked |
| independent module, the terms and conditions of the license of that |
| module. An independent module is a module which is not derived from |
| or based on this library. If you modify this library, you may extend |
| this exception to your version of the library, but you are not |
| obligated to do so. If you do not wish to do so, delete this |
| exception statement from your version. */ |
| |
| package javax.xml.xpath; |
| |
| import java.io.BufferedReader; |
| import java.io.File; |
| import java.io.FileInputStream; |
| import java.io.InputStream; |
| import java.io.InputStreamReader; |
| import java.io.IOException; |
| import java.util.Properties; |
| |
| /** |
| * Factory for creating XPath environments. |
| * |
| * @author (a href='mailto:dog@gnu.org'>Chris Burdess</a) |
| * @since 1.3 |
| */ |
| public abstract class XPathFactory |
| { |
| |
| /** |
| * The default property name according to the JAXP specification. |
| */ |
| public static final String DEFAULT_PROPERTY_NAME = |
| "javax.xml.xpath.XPathFactory"; |
| |
| /** |
| * The default object model URI. |
| */ |
| public static final String DEFAULT_OBJECT_MODEL_URI = |
| XPathConstants.DOM_OBJECT_MODEL; |
| |
| protected XPathFactory() |
| { |
| } |
| |
| /** |
| * Returns a new factory for the default (DOM) object model. |
| */ |
| public static final XPathFactory newInstance() |
| { |
| try |
| { |
| return newInstance(DEFAULT_OBJECT_MODEL_URI); |
| } |
| catch (XPathFactoryConfigurationException e) |
| { |
| throw new RuntimeException(e.getMessage()); |
| } |
| } |
| |
| /** |
| * Returns a new factory for the given object model URI. |
| * The implementation class to load is the first found in the following |
| * locations that advertises support for the given model URI: |
| * <ol> |
| * <li>the <code>javax.xml.xpath.XPathFactory</code> system property</li> |
| * <li>the above named property value in the |
| * <code><i>$JAVA_HOME</i>/lib/jaxp.properties</code> file</li> |
| * <li>the class name specified in the |
| * <code>META-INF/services/javax.xml.xpath.XPathFactory</code> system |
| * resource</li> |
| * <li>the default factory class</li> |
| * </ol> |
| * @param uri the object model URI |
| */ |
| public static final XPathFactory newInstance(String uri) |
| throws XPathFactoryConfigurationException |
| { |
| ClassLoader loader = Thread.currentThread().getContextClassLoader(); |
| if (loader == null) |
| { |
| loader = XPathFactory.class.getClassLoader(); |
| } |
| String className = null; |
| int count = 0; |
| do |
| { |
| className = getFactoryClassName(loader, count++); |
| if (className != null) |
| { |
| try |
| { |
| Class t = (loader != null) ? loader.loadClass(className) : |
| Class.forName(className); |
| XPathFactory ret = (XPathFactory) t.newInstance(); |
| if (ret.isObjectModelSupported(uri)) |
| { |
| return ret; |
| } |
| className = null; |
| } |
| catch (ClassNotFoundException e) |
| { |
| className = null; |
| } |
| catch (Exception e) |
| { |
| throw new XPathFactoryConfigurationException(e); |
| } |
| } |
| } |
| while (className == null && count < 4); |
| String msg = "no factories with support for " + uri; |
| throw new XPathFactoryConfigurationException(msg); |
| } |
| |
| private static String getFactoryClassName(ClassLoader loader, int attempt) |
| { |
| final String propertyName = DEFAULT_PROPERTY_NAME; |
| switch (attempt) |
| { |
| case 0: |
| return System.getProperty(propertyName); |
| case 1: |
| try |
| { |
| File file = new File(System.getProperty("java.home")); |
| file = new File(file, "lib"); |
| file = new File(file, "jaxp.properties"); |
| InputStream in = new FileInputStream(file); |
| Properties props = new Properties(); |
| props.load(in); |
| in.close(); |
| return props.getProperty(propertyName); |
| } |
| catch (IOException e) |
| { |
| return null; |
| } |
| case 2: |
| try |
| { |
| String serviceKey = "/META-INF/services/" + propertyName; |
| InputStream in = (loader != null) ? |
| loader.getResourceAsStream(serviceKey) : |
| XPathFactory.class.getResourceAsStream(serviceKey); |
| if (in != null) |
| { |
| BufferedReader r = |
| new BufferedReader(new InputStreamReader(in)); |
| String ret = r.readLine(); |
| r.close(); |
| return ret; |
| } |
| } |
| catch (IOException e) |
| { |
| } |
| return null; |
| case 3: |
| return "gnu.xml.xpath.XPathFactoryImpl"; |
| default: |
| return null; |
| } |
| } |
| |
| /** |
| * Indicates whether the specified object model URI is supported by |
| * this factory. |
| */ |
| public abstract boolean isObjectModelSupported(String objectModel); |
| |
| /** |
| * Sets the state of the named feature. |
| */ |
| public abstract void setFeature(String name, boolean value) |
| throws XPathFactoryConfigurationException; |
| |
| /** |
| * Returns the state of the named feature. |
| */ |
| public abstract boolean getFeature(String name) |
| throws XPathFactoryConfigurationException; |
| |
| /** |
| * Sets the XPath variable resolver calback. |
| */ |
| public abstract void setXPathVariableResolver(XPathVariableResolver resolver); |
| |
| /** |
| * Sets the XPath extension function resolver calback. |
| */ |
| public abstract void setXPathFunctionResolver(XPathFunctionResolver resolver); |
| |
| /** |
| * Returns a new XPath evaluation environment. |
| */ |
| public abstract XPath newXPath(); |
| |
| } |