zongaro 2003/12/04 12:58:35
Modified: java/src/org/apache/xml/utils Tag: xslt20-compiled
ObjectFactory.java
Log:
Factored out part of ObjectFactory's createObject method into separately
callable lookUpFactoryClass and lookUpFactoryClassName methods. This allows
the caller to cache the Class object that provides a service at an appropriate
level, and create new instances of that class at will, rather than going
through the expensive service provider look-up procedure for each and every
object created.
Revision Changes Path
No revision
No revision
1.1.2.1 +150 -31
xml-xalan/java/src/org/apache/xml/utils/ObjectFactory.java
Index: ObjectFactory.java
===================================================================
RCS file:
/home/cvs/xml-xalan/java/src/org/apache/xml/utils/ObjectFactory.java,v
retrieving revision 1.1
retrieving revision 1.1.2.1
diff -u -r1.1 -r1.1.2.1
--- ObjectFactory.java 14 Aug 2003 16:29:19 -0000 1.1
+++ ObjectFactory.java 4 Dec 2003 20:58:35 -0000 1.1.2.1
@@ -120,7 +120,7 @@
* <li>use fallback classname
* </ol>
*
- * @return Class object of factory, never null
+ * @return instance of factory, never null
*
* @param factoryId Name of the factory to find, same as
* a property name
@@ -144,7 +144,7 @@
* <li>use fallback classname
* </ol>
*
- * @return Class object of factory, never null
+ * @return instance of factory, never null
*
* @param factoryId Name of the factory to find, same as
* a property name
@@ -161,25 +161,152 @@
String fallbackClassName)
throws ConfigurationError
{
- debugPrintln("debug is on");
+ Class factoryClass = lookUpFactoryClass(factoryId,
+ propertiesFilename,
+ fallbackClassName);
- SecuritySupport ss = SecuritySupport.getInstance();
+ if (factoryClass == null) {
+ throw new ConfigurationError(
+ "Provider for " + factoryId + " cannot be found", null);
+ }
+
+ try{
+ Object instance = factoryClass.newInstance();
+ debugPrintln("created new instance of factory " + factoryId);
+ return instance;
+ } catch (Exception x) {
+ throw new ConfigurationError(
+ "Provider for factory " + factoryId
+ + " could not be instantiated: " + x, x);
+ }
+ } // createObject(String,String,String):Object
+
+ /**
+ * Finds the implementation Class object in the specified order. The
+ * specified order is the following:
+ * <ol>
+ * <li>query the system property using <code>System.getProperty</code>
+ * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
+ * <li>read <code>META-INF/services/<i>factoryId</i></code> file
+ * <li>use fallback classname
+ * </ol>
+ *
+ * @return Class object of factory, never null
+ *
+ * @param factoryId Name of the factory to find, same as
+ * a property name
+ * @param propertiesFilename The filename in the $java.home/lib directory
+ * of the properties file. If none specified,
+ * ${java.home}/lib/xalan.properties will be
used.
+ * @param fallbackClassName Implementation class name, if nothing
else
+ * is found. Use null to mean no fallback.
+ *
+ * @exception ObjectFactory.ConfigurationError
+ */
+ public static Class lookUpFactoryClass(String factoryId)
+ throws ConfigurationError
+ {
+ return lookUpFactoryClass(factoryId, null, null);
+ } // lookUpFactoryClass(String):Class
+
+ /**
+ * Finds the implementation Class object in the specified order. The
+ * specified order is the following:
+ * <ol>
+ * <li>query the system property using <code>System.getProperty</code>
+ * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
+ * <li>read <code>META-INF/services/<i>factoryId</i></code> file
+ * <li>use fallback classname
+ * </ol>
+ *
+ * @return Class object that provides factory service, never null
+ *
+ * @param factoryId Name of the factory to find, same as
+ * a property name
+ * @param propertiesFilename The filename in the $java.home/lib directory
+ * of the properties file. If none specified,
+ * ${java.home}/lib/xalan.properties will be
used.
+ * @param fallbackClassName Implementation class name, if nothing
else
+ * is found. Use null to mean no fallback.
+ *
+ * @exception ObjectFactory.ConfigurationError
+ */
+ public static Class lookUpFactoryClass(String factoryId,
+ String propertiesFilename,
+ String fallbackClassName)
+ throws ConfigurationError
+ {
+ String factoryClassName = lookUpFactoryClassName(factoryId,
+ propertiesFilename,
+ fallbackClassName);
ClassLoader cl = findClassLoader();
+ if (factoryClassName == null) {
+ factoryClassName = fallbackClassName;
+ }
+
+ // assert(className != null);
+ try{
+ Class providerClass = findProviderClass(factoryClassName,
+ cl,
+ true);
+ debugPrintln("created new instance of " + providerClass +
+ " using ClassLoader: " + cl);
+ return providerClass;
+ } catch (ClassNotFoundException x) {
+ throw new ConfigurationError(
+ "Provider " + factoryClassName + " not found", x);
+ } catch (Exception x) {
+ throw new ConfigurationError(
+ "Provider "+factoryClassName+" could not be instantiated:
"+x,
+ x);
+ }
+ } // lookUpFactoryClass(String,String,String):Class
+
+ /**
+ * Finds the name of the required implementation class in the specified
+ * order. The specified order is the following:
+ * <ol>
+ * <li>query the system property using <code>System.getProperty</code>
+ * <li>read <code>$java.home/lib/<i>propertiesFilename</i></code> file
+ * <li>read <code>META-INF/services/<i>factoryId</i></code> file
+ * <li>use fallback classname
+ * </ol>
+ *
+ * @return name of class that provides factory service, never null
+ *
+ * @param factoryId Name of the factory to find, same as
+ * a property name
+ * @param propertiesFilename The filename in the $java.home/lib directory
+ * of the properties file. If none specified,
+ * ${java.home}/lib/xalan.properties will be
used.
+ * @param fallbackClassName Implementation class name, if nothing
else
+ * is found. Use null to mean no fallback.
+ *
+ * @exception ObjectFactory.ConfigurationError
+ */
+ public static String lookUpFactoryClassName(String factoryId,
+ String propertiesFilename,
+ String fallbackClassName)
+ {
+ SecuritySupport ss = SecuritySupport.getInstance();
+
// Use the system property first
try {
String systemProp = ss.getSystemProperty(factoryId);
if (systemProp != null) {
debugPrintln("found system property, value=" + systemProp);
- return newInstance(systemProp, cl, true);
+ return systemProp;
}
} catch (SecurityException se) {
// Ignore and continue w/ next location
}
- // Try to read from propertiesFilename, or
$java.home/lib/xalan.properties
+ // Try to read from propertiesFilename, or
+ // $java.home/lib/xalan.properties
String factoryClassName = null;
- // no properties file name specified; use
$JAVA_HOME/lib/xalan.properties:
+ // no properties file name specified; use
+ // $JAVA_HOME/lib/xalan.properties:
if (propertiesFilename == null) {
File propertiesFile = null;
boolean propertiesFileExists = false;
@@ -218,9 +345,11 @@
} // else, nothing's changed
}
if(loadProperties) {
- // must never have attempted to read
xalan.properties before (or it's outdeated)
+ // must never have attempted to read xalan.properties
+ // before (or it's outdeated)
fXalanProperties = new Properties();
- FileInputStream fis =
ss.getFileInputStream(propertiesFile);
+ FileInputStream fis =
+
ss.getFileInputStream(propertiesFile);
fXalanProperties.load(fis);
fis.close();
}
@@ -237,7 +366,8 @@
}
} else {
try {
- FileInputStream fis = ss.getFileInputStream(new
File(propertiesFilename));
+ FileInputStream fis =
+ ss.getFileInputStream(new
File(propertiesFilename));
Properties props = new Properties();
props.load(fis);
fis.close();
@@ -249,24 +379,14 @@
}
}
if (factoryClassName != null) {
- debugPrintln("found in " + propertiesFilename + ", value=" +
factoryClassName);
- return newInstance(factoryClassName, cl, true);
+ debugPrintln("found in " + propertiesFilename + ", value="
+ + factoryClassName);
+ return factoryClassName;
}
// Try Jar Service Provider Mechanism
- Object provider = findJarServiceProvider(factoryId);
- if (provider != null) {
- return provider;
- }
-
- if (fallbackClassName == null) {
- throw new ConfigurationError(
- "Provider for " + factoryId + " cannot be found", null);
- }
-
- debugPrintln("using fallback, value=" + fallbackClassName);
- return newInstance(fallbackClassName, cl, true);
- } // createObject(String,String,String):Object
+ return findJarServiceProviderName(factoryId);
+ } // lookUpFactoryClass(String,String):String
//
// Private static methods
@@ -367,7 +487,7 @@
* Find a Class using the specified ClassLoader
*/
public static Class findProviderClass(String className, ClassLoader cl,
- boolean doFallback)
+ boolean doFallback)
throws ClassNotFoundException, ConfigurationError
{
Class providerClass;
@@ -406,13 +526,12 @@
return providerClass;
}
- /*
- * Try to find provider using Jar Service Provider Mechanism
+ /**
+ * Find the name of service provider using Jar Service Provider Mechanism
*
* @return instance of provider class if found or null
*/
- private static Object findJarServiceProvider(String factoryId)
- throws ConfigurationError
+ private static String findJarServiceProviderName(String factoryId)
{
SecuritySupport ss = SecuritySupport.getInstance();
String serviceId = "META-INF/services/" + factoryId;
@@ -483,7 +602,7 @@
// ClassLoader because we want to avoid the case where the
// resource file was found using one ClassLoader and the
// provider class was instantiated using a different one.
- return newInstance(factoryClassName, cl, false);
+ return factoryClassName;
}
// No provider found
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