Siphalor/tweed5-commons-logging
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Resolve NullPointerExceptions, remove redundant checks, minor refactoring to facilitate readability.

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git-svn-id: https://svn.apache.org/repos/asf/jakarta/commons/proper/logging/trunk@138890 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Richard A. Sitze
2002-06-11 22:29:14 +00:00
parent 83e704b910
commit 470f3338d0
1 changed files with 110 additions and 67 deletions
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157
src/java/org/apache/commons/logging/LogFactory.java
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@@ -1,7 +1,7 @@
/*
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//logging/src/java/org/apache/commons/logging/LogFactory.java,v 1.7 2002/05/04 19:50:29 sanders Exp $
* $Revision: 1.7 $
* $Date: 2002/05/04 19:50:29 $
* $Header: /home/jerenkrantz/tmp/commons/commons-convert/cvs/home/cvs/jakarta-commons//logging/src/java/org/apache/commons/logging/LogFactory.java,v 1.8 2002/06/11 22:29:14 rsitze Exp $
* $Revision: 1.8 $
* $Date: 2002/06/11 22:29:14 $
*
* ====================================================================
*
@@ -71,6 +71,7 @@ import java.lang.reflect.Method;
import java.util.Enumeration;
import java.util.Hashtable;
import java.util.Properties;
import java.lang.SecurityException;
/**
@@ -84,7 +85,7 @@ import java.util.Properties;
*
* @author Craig R. McClanahan
* @author Costin Manolache
* @version $Revision: 1.7 $ $Date: 2002/05/04 19:50:29 $
* @version $Revision: 1.8 $ $Date: 2002/06/11 22:29:14 $
*/
public abstract class LogFactory {
@@ -257,22 +258,21 @@ public abstract class LogFactory {
public static LogFactory getFactory() throws LogConfigurationException {
// Identify the class loader we will be using
ClassLoader classLoader = findClassLoader();
ClassLoader contextClassLoader = getContextClassLoader();
// Return any previously registered factory for this class loader
LogFactory factory = (LogFactory) factories.get(classLoader);
if (factory != null) {
return (factory);
}
LogFactory factory = getCachedFactory(contextClassLoader);
if (factory != null)
return factory;
// First, try the system property
try {
String factoryClass = System.getProperty(FACTORY_PROPERTY);
if (factoryClass != null) {
factory = newFactory(factoryClass, classLoader);
factory = newFactory(factoryClass, contextClassLoader);
}
} catch (SecurityException e) {
;
; // ignore
}
// Second, try to find a service by using the JDK1.3 jar
@@ -281,14 +281,11 @@ public abstract class LogFactory {
// CLASSPATH or equivalent ). This is similar with the second
// step, except that it uses the (standard?) jdk1.3 location in the jar.
if( factory==null ) {
if (factory == null) {
try {
InputStream is=null;
if (classLoader == null) {
is=ClassLoader.getSystemResourceAsStream( SERVICE_ID );
} else {
is=classLoader.getResourceAsStream( SERVICE_ID );
}
InputStream is = (contextClassLoader == null
? ClassLoader.getSystemResourceAsStream( SERVICE_ID )
: contextClassLoader.getResourceAsStream( SERVICE_ID ));
if( is != null ) {
// This code is needed by EBCDIC and other strange systems.
@@ -306,7 +303,7 @@ public abstract class LogFactory {
if (factoryClassName != null &&
! "".equals(factoryClassName)) {
factory= newFactory( factoryClassName, classLoader );
factory= newFactory( factoryClassName, contextClassLoader );
}
}
} catch( Exception ex ) {
@@ -327,7 +324,7 @@ public abstract class LogFactory {
try {
InputStream stream =
classLoader.getResourceAsStream(FACTORY_PROPERTIES);
contextClassLoader.getResourceAsStream(FACTORY_PROPERTIES);
if (stream != null) {
props = new Properties();
props.load(stream);
@@ -337,7 +334,7 @@ public abstract class LogFactory {
if (factoryClass == null) {
factoryClass = FACTORY_DEFAULT;
}
factory = newFactory(factoryClass, classLoader);
factory = newFactory(factoryClass, contextClassLoader);
}
}
// the properties will be set at the end.
@@ -359,10 +356,7 @@ public abstract class LogFactory {
}
}
// Cache and return the new factory instance
factories.put(classLoader, factory);
return (factory);
return factory;
}
@@ -428,51 +422,92 @@ public abstract class LogFactory {
/**
* Return the class loader to be used for loading the selected
* <code>LogFactory</code> implementation class. On a JDK 1.2 or later
* system, the context class loader for the current thread will be used
* if it is present.
* Return the thread context class loader if available.
* Otherwise return null.
*
* The thread context class loader is available for JDK 1.2
* or later, if certain security conditions are met.
*
* @exception LogConfigurationException if a suitable class loader
* cannot be identified
* cannot be identified.
*/
protected static ClassLoader findClassLoader()
throws LogConfigurationException {
protected static ClassLoader getContextClassLoader()
throws LogConfigurationException
{
ClassLoader classLoader = null;
// Are we running on a JDK 1.2 or later system?
Method method = null;
try {
method = Thread.class.getMethod("getContextClassLoader", null);
} catch (NoSuchMethodException e) {
// Assume we are running on JDK 1.1
return (LogFactory.class.getClassLoader());
}
// Are we running on a JDK 1.2 or later system?
Method method = Thread.class.getMethod("getContextClassLoader", null);
// Get the thread context class loader (if there is one)
ClassLoader classLoader = null;
try {
classLoader = (ClassLoader)
method.invoke(Thread.currentThread(), null);
if (classLoader == null) {
classLoader = LogFactory.class.getClassLoader();
}
classLoader = (ClassLoader)method.invoke(Thread.currentThread(), null);
} catch (IllegalAccessException e) {
throw new LogConfigurationException
("Unexpected IllegalAccessException", e);
} catch (InvocationTargetException e) {
/**
* InvocationTargetException is thrown by 'invoke' when
* the method being invoked (getContextClassLoader) throws
* an exception.
*
* getContextClassLoader() throws SecurityException when
* the context class loader isn't an ancestor of the
* calling class's class loader, or if security
* permissions are restricted.
*
* In the first case (not related), we want to ignore and
* keep going. We cannot help but also ignore the second
* with the logic below, but other calls elsewhere (to
* obtain a class loader) will trigger this exception where
* we can make a distinction.
*/
if (e.getTargetException() instanceof SecurityException) {
; // ignore
} else {
// Capture 'e.getTargetException()' exception for details
// alternate: log 'e.getTargetException()', and pass back 'e'.
throw new LogConfigurationException
("Unexpected InvocationTargetException", e);
("Unexpected InvocationTargetException", e.getTargetException());
}
}
} catch (NoSuchMethodException e) {
// Assume we are running on JDK 1.1
classLoader = LogFactory.class.getClassLoader();
}
// Return the selected class loader
return (classLoader);
return classLoader;
}
/**
* Check cached factories (keyed by classLoader)
*/
private static LogFactory getCachedFactory(ClassLoader contextClassLoader)
{
LogFactory factory = null;
if (contextClassLoader != null)
factory = (LogFactory) factories.get(contextClassLoader);
if (factory==null)
factory = (LogFactory) factories.get(LogFactory.class.getClassLoader());
return factory;
}
private static void cacheFactory(ClassLoader classLoader, LogFactory factory)
{
if (classLoader != null && factory != null)
factories.put(classLoader, factory);
}
/**
* Return a new instance of the specified <code>LogFactory</code>
* implementation class, loaded by the specified class loader.
* If that fails, try the class loader used to load this
* (abstract) LogFactory.
*
* @param factoryClass Fully qualified name of the <code>LogFactory</code>
* implementation class
@@ -487,21 +522,29 @@ public abstract class LogFactory {
{
try {
if (classLoader == null)
classLoader = LogFactory.class.getClassLoader();
Class clazz = null;
if (classLoader == null) {
clazz = Class.forName(factoryClass);
} else {
try {
// first the thread class loader
clazz = classLoader.loadClass(factoryClass);
} catch( ClassNotFoundException ex ) {
// if this failed ( i.e. no implementation is
// found in the webapp itself ) try the
// caller's loader
clazz = Class.forName( factoryClass );
} catch (ClassNotFoundException ex) {
// if this failed (i.e. no implementation is
// found in the webapp), try the caller's loader
// if we haven't already...
if (classLoader != LogFactory.class.getClassLoader()) {
classLoader = LogFactory.class.getClassLoader();
clazz = classLoader.loadClass(factoryClass);
}
}
return ((LogFactory) clazz.newInstance());
LogFactory factory = (LogFactory)clazz.newInstance();
// Cache using correct classLoader
cacheFactory(classLoader, factory);
return factory;
} catch (Exception e) {
throw new LogConfigurationException(e);
}