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The MyFaces Commons Subproject provides base classes for usage in both the
MyFaces implementation and the MyFaces Tomahawk components. This is also
a general set of utility classes for usage in your JSF projects independent
of the implementation you might be deciding upon.
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/*
* Copyright 2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.myfaces.util;
import org.apache.commons.el.Coercions;
import org.apache.commons.el.Logger;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import javax.faces.FacesException;
import javax.servlet.jsp.el.ELException;
import java.io.InputStream;
import java.io.IOException;
import java.lang.reflect.Array;
import java.util.*;
/**
* @author Manfred Geiler (latest modification by $Author: manolito $)
* @author Anton Koinov
* @version $Revision: 265527 $ $Date: 2005-08-31 16:32:30 +0000 (Wed, 31 Aug 2005) $
*/
public class ClassUtils
{
//~ Static fields/initializers -----------------------------------------------------------------
private static final Log log = LogFactory.getLog(ClassUtils.class);
private static final Logger COERCION_LOGGER = new Logger(System.out);
public static final Class BOOLEAN_ARRAY_CLASS = boolean[].class;
public static final Class BYTE_ARRAY_CLASS = byte[].class;
public static final Class CHAR_ARRAY_CLASS = char[].class;
public static final Class SHORT_ARRAY_CLASS = short[].class;
public static final Class INT_ARRAY_CLASS = int[].class;
public static final Class LONG_ARRAY_CLASS = long[].class;
public static final Class FLOAT_ARRAY_CLASS = float[].class;
public static final Class DOUBLE_ARRAY_CLASS = double[].class;
public static final Class OBJECT_ARRAY_CLASS = Object[].class;
public static final Class BOOLEAN_OBJECT_ARRAY_CLASS = Boolean[].class;
public static final Class BYTE_OBJECT_ARRAY_CLASS = Byte[].class;
public static final Class CHARACTER_OBJECT_ARRAY_CLASS = Character[].class;
public static final Class SHORT_OBJECT_ARRAY_CLASS = Short[].class;
public static final Class INTEGER_OBJECT_ARRAY_CLASS = Integer[].class;
public static final Class LONG_OBJECT_ARRAY_CLASS = Long[].class;
public static final Class FLOAT_OBJECT_ARRAY_CLASS = Float[].class;
public static final Class DOUBLE_OBJECT_ARRAY_CLASS = Double[].class;
public static final Class STRING_OBJECT_ARRAY_CLASS = String[].class;
public static final Map COMMON_TYPES = new HashMap(64);
static
{
COMMON_TYPES.put("byte", Byte.TYPE);
COMMON_TYPES.put("char", Character.TYPE);
COMMON_TYPES.put("double", Double.TYPE);
COMMON_TYPES.put("float", Float.TYPE);
COMMON_TYPES.put("int", Integer.TYPE);
COMMON_TYPES.put("long", Long.TYPE);
COMMON_TYPES.put("short", Short.TYPE);
COMMON_TYPES.put("boolean", Boolean.TYPE);
COMMON_TYPES.put("void", Void.TYPE);
COMMON_TYPES.put("java.lang.Object", Object.class);
COMMON_TYPES.put("java.lang.Boolean", Boolean.class);
COMMON_TYPES.put("java.lang.Byte", Byte.class);
COMMON_TYPES.put("java.lang.Character", Character.class);
COMMON_TYPES.put("java.lang.Short", Short.class);
COMMON_TYPES.put("java.lang.Integer", Integer.class);
COMMON_TYPES.put("java.lang.Long", Long.class);
COMMON_TYPES.put("java.lang.Float", Float.class);
COMMON_TYPES.put("java.lang.Double", Double.class);
COMMON_TYPES.put("java.lang.String", String.class);
COMMON_TYPES.put("byte[]", BYTE_ARRAY_CLASS);
COMMON_TYPES.put("char[]", CHAR_ARRAY_CLASS);
COMMON_TYPES.put("double[]", DOUBLE_ARRAY_CLASS);
COMMON_TYPES.put("float[]", FLOAT_ARRAY_CLASS);
COMMON_TYPES.put("int[]", INT_ARRAY_CLASS);
COMMON_TYPES.put("long[]", LONG_ARRAY_CLASS);
COMMON_TYPES.put("short[]", SHORT_ARRAY_CLASS);
COMMON_TYPES.put("boolean[]", BOOLEAN_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Object[]", OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Boolean[]", BOOLEAN_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Byte[]", BYTE_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Character[]", CHARACTER_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Short[]", SHORT_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Integer[]", INTEGER_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Long[]", LONG_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Float[]", FLOAT_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.Double[]", DOUBLE_OBJECT_ARRAY_CLASS);
COMMON_TYPES.put("java.lang.String[]", STRING_OBJECT_ARRAY_CLASS);
// array of void is not a valid type
}
/** utility class, do not instantiate */
private ClassUtils()
{
// utility class, disable instantiation
}
//~ Methods ------------------------------------------------------------------------------------
/**
* Tries a Class.forName with the context class loader of the current thread first and
* automatically falls back to the ClassUtils class loader (i.e. the loader of the
* myfaces.jar lib) if necessary.
*
* @param type fully qualified name of a non-primitive non-array class
* @return the corresponding Class
* @throws NullPointerException if type is null
* @throws ClassNotFoundException
*/
public static Class classForName(String type)
throws ClassNotFoundException
{
if (type == null) throw new NullPointerException("type");
try
{
// Try WebApp ClassLoader first
return Class.forName(type,
false, // do not initialize for faster startup
Thread.currentThread().getContextClassLoader());
}
catch (ClassNotFoundException ignore)
{
// fallback: Try ClassLoader for ClassUtils (i.e. the myfaces.jar lib)
return Class.forName(type,
false, // do not initialize for faster startup
ClassUtils.class.getClassLoader());
}
}
/**
* Same as {@link #classForName(String)}, but throws a RuntimeException
* (FacesException) instead of a ClassNotFoundException.
*
* @return the corresponding Class
* @throws NullPointerException if type is null
* @throws FacesException if class not found
*/
public static Class simpleClassForName(String type)
{
try
{
return classForName(type);
}
catch (ClassNotFoundException e)
{
log.error("Class " + type + " not found", e);
throw new FacesException(e);
}
}
/**
* Similar as {@link #classForName(String)}, but also supports primitive types
* and arrays as specified for the JavaType element in the JavaServer Faces Config DTD.
*
* @param type fully qualified class name or name of a primitive type, both optionally
* followed by "[]" to indicate an array type
* @return the corresponding Class
* @throws NullPointerException if type is null
* @throws ClassNotFoundException
*/
public static Class javaTypeToClass(String type)
throws ClassNotFoundException
{
if (type == null) throw new NullPointerException("type");
// try common types and arrays of common types first
Class clazz = (Class) COMMON_TYPES.get(type);
if (clazz != null)
{
return clazz;
}
int len = type.length();
if (len > 2 && type.charAt(len - 1) == ']' && type.charAt(len - 2) == '[')
{
String componentType = type.substring(0, len - 2);
Class componentTypeClass = classForName(componentType);
return Array.newInstance(componentTypeClass, 0).getClass();
}
else
{
return classForName(type);
}
}
/**
* Same as {@link #javaTypeToClass(String)}, but throws a RuntimeException
* (FacesException) instead of a ClassNotFoundException.
*
* @return the corresponding Class
* @throws NullPointerException if type is null
* @throws FacesException if class not found
*/
public static Class simpleJavaTypeToClass(String type)
{
try
{
return javaTypeToClass(type);
}
catch (ClassNotFoundException e)
{
log.error("Class " + type + " not found", e);
throw new FacesException(e);
}
}
public static InputStream getResourceAsStream(String resource)
{
InputStream stream = Thread.currentThread().getContextClassLoader()
.getResourceAsStream(resource);
if (stream == null)
{
// fallback
stream = ClassUtils.class.getClassLoader().getResourceAsStream(resource);
}
return stream;
}
/**
* @param resource Name of resource(s) to find in classpath
* @param defaultObject The default object to use to determine the class loader (if none associated with current thread.)
* @return Iterator over URL Objects
*/
public static Iterator getResources(String resource, Object defaultObject)
{
try
{
Enumeration resources = getCurrentLoader(defaultObject).getResources(resource);
List lst = new ArrayList();
while (resources.hasMoreElements())
{
lst.add(resources.nextElement());
}
return lst.iterator();
}
catch (IOException e)
{
log.error(e.getMessage(), e);
throw new FacesException(e);
}
}
public static Object newInstance(String type)
throws FacesException
{
if (type == null) return null;
return newInstance(simpleClassForName(type));
}
public static Object newInstance(Class clazz)
throws FacesException
{
try
{
return clazz.newInstance();
}
catch(NoClassDefFoundError e)
{
log.error("Class : "+clazz.getName()+" not found.",e);
throw new FacesException(e);
}
catch (InstantiationException e)
{
log.error(e.getMessage(), e);
throw new FacesException(e);
}
catch (IllegalAccessException e)
{
log.error(e.getMessage(), e);
throw new FacesException(e);
}
}
public static Object convertToType(Object value, Class desiredClass)
{
if (value == null) return null;
try
{
// Use coersion implemented by JSP EL for consistency with EL
// expressions. Additionally, it caches some of the coersions.
return Coercions.coerce(value, desiredClass, COERCION_LOGGER);
}
catch (ELException e)
{
String message = "Cannot coerce " + value.getClass().getName()
+ " to " + desiredClass.getName();
log.error(message, e);
throw new FacesException(message, e);
}
}
/**
* Gets the ClassLoader associated with the current thread. Returns the class loader associated with
* the specified default object if no context loader is associated with the current thread.
*
* @param defaultObject The default object to use to determine the class loader (if none associated with current thread.)
* @return ClassLoader
*/
protected static ClassLoader getCurrentLoader(Object defaultObject)
{
ClassLoader loader = Thread.currentThread().getContextClassLoader();
if(loader == null)
{
loader = defaultObject.getClass().getClassLoader();
}
return loader;
}
}
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