org.jboss.util.Classes Maven / Gradle / Ivy
/*
* JBoss, Home of Professional Open Source
* Copyright 2005, JBoss Inc., and individual contributors as indicated
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*/
package org.jboss.util;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.lang.reflect.Array;
import java.lang.NoSuchMethodException;
import java.net.URL;
import java.security.AccessController;
import java.security.CodeSource;
import java.security.PrivilegedAction;
import java.security.ProtectionDomain;
import java.util.*;
/**
* A collection of Class utilities.
*
* @version $Revision: 2787 $
* @author Jason Dillon
* @author Scott Stark
* @author Dimitris Andreadis
*/
@SuppressWarnings("unchecked")
public final class Classes
{
/** The string used to separator packages */
public static final String PACKAGE_SEPARATOR = ".";
/** The characther used to separator packages */
public static final char PACKAGE_SEPARATOR_CHAR = '.';
/** The default package name. */
public static final String DEFAULT_PACKAGE_NAME = "";
/** Format a string buffer containing the Class, Interfaces, CodeSource,
and ClassLoader information for the given object clazz.
@param clazz the Class
@param results - the buffer to write the info to
*/
public static void displayClassInfo(Class clazz, StringBuffer results)
{
// Print out some codebase info for the clazz
ClassLoader cl = clazz.getClassLoader();
results.append("\n");
results.append(clazz.getName());
results.append("(");
results.append(Integer.toHexString(clazz.hashCode()));
results.append(").ClassLoader=");
results.append(cl);
ClassLoader parent = cl;
while( parent != null )
{
results.append("\n..");
results.append(parent);
URL[] urls = getClassLoaderURLs(parent);
int length = urls != null ? urls.length : 0;
for(int u = 0; u < length; u ++)
{
results.append("\n....");
results.append(urls[u]);
}
if( parent != null )
parent = parent.getParent();
}
CodeSource clazzCS = clazz.getProtectionDomain().getCodeSource();
if( clazzCS != null )
{
results.append("\n++++CodeSource: ");
results.append(clazzCS);
}
else
results.append("\n++++Null CodeSource");
results.append("\nImplemented Interfaces:");
Class[] ifaces = clazz.getInterfaces();
for(int i = 0; i < ifaces.length; i ++)
{
Class iface = ifaces[i];
results.append("\n++");
results.append(iface);
results.append("(");
results.append(Integer.toHexString(iface.hashCode()));
results.append(")");
ClassLoader loader = ifaces[i].getClassLoader();
results.append("\n++++ClassLoader: ");
results.append(loader);
ProtectionDomain pd = ifaces[i].getProtectionDomain();
CodeSource cs = pd.getCodeSource();
if( cs != null )
{
results.append("\n++++CodeSource: ");
results.append(cs);
}
else
results.append("\n++++Null CodeSource");
}
}
/** Use reflection to access a URL[] getURLs or URL[] getClasspath method so
that non-URLClassLoader class loaders, or class loaders that override
getURLs to return null or empty, can provide the true classpath info.
* @param cl
* @return the urls
*/
public static URL[] getClassLoaderURLs(ClassLoader cl)
{
URL[] urls = {};
try
{
Class returnType = urls.getClass();
Class[] parameterTypes = {};
Class clClass = cl.getClass();
Method getURLs = clClass.getMethod("getURLs", parameterTypes);
if( returnType.isAssignableFrom(getURLs.getReturnType()) )
{
Object[] args = {};
urls = (URL[]) getURLs.invoke(cl, args);
}
if( urls == null || urls.length == 0 )
{
Method getCp = clClass.getMethod("getClasspath", parameterTypes);
if( returnType.isAssignableFrom(getCp.getReturnType()) )
{
Object[] args = {};
urls = (URL[]) getCp.invoke(cl, args);
}
}
}
catch(Exception ignore)
{
}
return urls;
}
/**
* Describe the class of an object
*
* @param object the object
* @return the description
*/
public static String getDescription(Object object)
{
StringBuffer buffer = new StringBuffer();
describe(buffer, object);
return buffer.toString();
}
/**
* Describe the class of an object
*
* @param buffer the string buffer
* @param object the object
*/
public static void describe(StringBuffer buffer, Object object)
{
if (object == null)
buffer.append("**null**");
else
describe(buffer, object.getClass());
}
/**
* Describe the class
*
* @param buffer the string buffer
* @param clazz the clazz
*/
public static void describe(StringBuffer buffer, Class clazz)
{
if (clazz == null)
buffer.append("**null**");
else
{
buffer.append("{class=").append(clazz.getName());
Class[] intfs = clazz.getInterfaces();
if (intfs.length > 0)
{
buffer.append(" intfs=");
for (int i = 0; i < intfs.length; ++i)
{
buffer.append(intfs[i].getName());
if (i < intfs.length-1)
buffer.append(", ");
}
}
buffer.append("}");
}
}
/**
* Get the short name of the specified class by striping off the package
* name.
*
* @param classname Class name.
* @return Short class name.
*/
public static String stripPackageName(final String classname)
{
int idx = classname.lastIndexOf(PACKAGE_SEPARATOR);
if (idx != -1)
return classname.substring(idx + 1, classname.length());
return classname;
}
/**
* Get the short name of the specified class by striping off the package
* name.
*
* @param type Class name.
* @return Short class name.
*/
public static String stripPackageName(final Class type)
{
return stripPackageName(type.getName());
}
/**
* Get the package name of the specified class.
*
* @param classname Class name.
* @return Package name or "" if the classname is in the
* default package.
*
* @throws EmptyStringException Classname is an empty string.
*/
public static String getPackageName(final String classname)
{
if (classname.length() == 0)
throw new EmptyStringException();
int index = classname.lastIndexOf(PACKAGE_SEPARATOR);
if (index != -1)
return classname.substring(0, index);
return "";
}
/**
* Get the package name of the specified class.
*
* @param type Class.
* @return Package name.
*/
public static String getPackageName(final Class type)
{
return getPackageName(type.getName());
}
/**
* Force the given class to be loaded fully.
*
* This method attempts to locate a static method on the given class
* the attempts to invoke it with dummy arguments in the hope that
* the virtual machine will prepare the class for the method call and
* call all of the static class initializers.
*
* @param type Class to force load.
*
* @throws NullArgumentException Type is null.
*/
public static void forceLoad(final Class type)
{
if (type == null)
throw new NullArgumentException("type");
// don't attempt to force primitives to load
if (type.isPrimitive()) return;
// don't attempt to force java.* classes to load
String packageName = Classes.getPackageName(type);
// System.out.println("package name: " + packageName);
if (packageName.startsWith("java.") ||
packageName.startsWith("javax."))
{
return;
}
// System.out.println("forcing class to load: " + type);
try
{
Method methods[] = type.getDeclaredMethods();
Method method = null;
for (int i = 0; i < methods.length; i++)
{
int modifiers = methods[i].getModifiers();
if (Modifier.isStatic(modifiers))
{
method = methods[i];
break;
}
}
if (method != null)
{
method.invoke(null, (Object[]) null);
}
else
{
type.newInstance();
}
}
catch (Exception ignore)
{
ThrowableHandler.add(ignore);
}
}
/////////////////////////////////////////////////////////////////////////
// Primitives //
/////////////////////////////////////////////////////////////////////////
/** Primitive type name -> class map. */
private static final Map PRIMITIVE_NAME_TYPE_MAP = new HashMap();
/** Setup the primitives map. */
static
{
PRIMITIVE_NAME_TYPE_MAP.put("boolean", Boolean.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("byte", Byte.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("char", Character.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("short", Short.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("int", Integer.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("long", Long.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("float", Float.TYPE);
PRIMITIVE_NAME_TYPE_MAP.put("double", Double.TYPE);
}
/**
* Get the primitive type for the given primitive name.
*
*
* For example, "boolean" returns Boolean.TYPE and so on...
*
* @param name Primitive type name (boolean, int, byte, ...)
* @return Primitive type or null.
*
* @exception IllegalArgumentException Type is not a primitive class
*/
public static Class getPrimitiveTypeForName(final String name)
{
return (Class) PRIMITIVE_NAME_TYPE_MAP.get(name);
}
/** Map of primitive types to their wrapper classes */
private static final Class[] PRIMITIVE_WRAPPER_MAP = {
Boolean.TYPE, Boolean.class,
Byte.TYPE, Byte.class,
Character.TYPE, Character.class,
Double.TYPE, Double.class,
Float.TYPE, Float.class,
Integer.TYPE, Integer.class,
Long.TYPE, Long.class,
Short.TYPE, Short.class,
};
/**
* Get the wrapper class for the given primitive type.
*
* @param type Primitive class.
* @return Wrapper class for primitive.
*
* @exception IllegalArgumentException Type is not a primitive class
*/
public static Class getPrimitiveWrapper(final Class type)
{
if (!type.isPrimitive())
{
throw new IllegalArgumentException("type is not a primitive class");
}
for (int i = 0; i < PRIMITIVE_WRAPPER_MAP.length; i += 2)
{
if (type.equals(PRIMITIVE_WRAPPER_MAP[i]))
return PRIMITIVE_WRAPPER_MAP[i + 1];
}
// should never get here, if we do then PRIMITIVE_WRAPPER_MAP
// needs to be updated to include the missing mapping
throw new UnreachableStatementException();
}
/**
* Populates a list with all the interfaces implemented by the argument
* class c and all its superclasses.
*
* @param allIfaces - the list to populate with the interfaces
* @param c - the class to start scanning for interfaces
*/
public static void getAllInterfaces(List allIfaces, Class c)
{
while (c != null)
{
Class[] ifaces = c.getInterfaces();
for (int n = 0; n < ifaces.length; n ++)
{
allIfaces.add(ifaces[n]);
}
c = c.getSuperclass();
}
}
/**
* Returns an array containing all the unique interfaces implemented
* by the argument class c and all its superclasses. Interfaces that
* appear multiple times through inheritence are only accounted for once.
*
* @param c - the class to start scanning for interfaces
* @return the interfaces
*/
public static Class[] getAllUniqueInterfaces(Class c)
{
Set uniqueIfaces = new HashSet();
while (c != null )
{
Class[] ifaces = c.getInterfaces();
for (int n = 0; n < ifaces.length; n ++)
{
uniqueIfaces.add(ifaces[n]);
}
c = c.getSuperclass();
}
return (Class[])uniqueIfaces.toArray(new Class[uniqueIfaces.size()]);
}
/**
* Check if the given class is a primitive wrapper class.
*
* @param type Class to check.
* @return True if the class is a primitive wrapper.
*/
public static boolean isPrimitiveWrapper(final Class type)
{
for (int i = 0; i < PRIMITIVE_WRAPPER_MAP.length; i += 2)
{
if (type.equals(PRIMITIVE_WRAPPER_MAP[i + 1]))
{
return true;
}
}
return false;
}
/**
* Check if the given class is a primitive class or a primitive
* wrapper class.
*
* @param type Class to check.
* @return True if the class is a primitive or primitive wrapper.
*/
public static boolean isPrimitive(final Class type)
{
if (type.isPrimitive() || isPrimitiveWrapper(type))
{
return true;
}
return false;
}
/** Check type against boolean, byte, char, short, int, long, float, double.
* @param type The java type name
* @return true if this is a primative type name.
*/
public static boolean isPrimitive(final String type)
{
return PRIMITIVE_NAME_TYPE_MAP.containsKey(type);
}
/**
* @param wrapper a primitive wrapper type
* @return primitive type the passed in wrapper type corresponds to
*/
public static Class getPrimitive(Class wrapper)
{
Class primitive;
if(Integer.class == wrapper)
{
primitive = int.class;
}
else if(Long.class == wrapper)
{
primitive = long.class;
}
else if(Double.class == wrapper)
{
primitive = double.class;
}
else if(Boolean.class == wrapper)
{
primitive = boolean.class;
}
else if(Short.class == wrapper)
{
primitive = short.class;
}
else if(Float.class == wrapper)
{
primitive = float.class;
}
else if(Byte.class == wrapper)
{
primitive = byte.class;
}
else if(Character.class == wrapper)
{
primitive = char.class;
}
else
{
throw new IllegalArgumentException("The class is not a primitive wrapper type: " + wrapper);
}
return primitive;
}
/**
* Instantiate a java class object
*
* @param expected the expected class type
* @param property the system property defining the class
* @param defaultClassName the default class name
* @return the instantiated object
*/
public static Object instantiate(Class expected, String property, String defaultClassName)
{
String className = getProperty(property, defaultClassName);
Class clazz = null;
try
{
clazz = loadClass(className);
}
catch (ClassNotFoundException e)
{
throw new NestedRuntimeException("Cannot load class " + className, e);
}
Object result = null;
try
{
result = clazz.newInstance();
}
catch (InstantiationException e)
{
throw new NestedRuntimeException("Error instantiating " + className, e);
}
catch (IllegalAccessException e)
{
throw new NestedRuntimeException("Error instantiating " + className, e);
}
if (expected.isAssignableFrom(clazz) == false)
throw new NestedRuntimeException("Class " + className + " from classloader " + clazz.getClassLoader() +
" is not of the expected class " + expected + " loaded from " + expected.getClassLoader());
return result;
}
/////////////////////////////////////////////////////////////////////////
// Class Loading //
/////////////////////////////////////////////////////////////////////////
/**
* This method acts equivalently to invoking
* Thread.currentThread().getContextClassLoader().loadClass(className); but it also
* supports primitive types and array classes of object types or primitive types.
*
* @param className the qualified name of the class or the name of primitive type or
* array in the same format as returned by the
* java.lang.Class.getName() method.
* @return the Class object for the requested className
*
* @throws ClassNotFoundException when the classLoader can not find the requested class
*/
public static Class loadClass(String className) throws ClassNotFoundException
{
return loadClass(className, Thread.currentThread().getContextClassLoader());
}
/**
* This method acts equivalently to invoking classLoader.loadClass(className)
* but it also supports primitive types and array classes of object types or
* primitive types.
*
* @param className the qualified name of the class or the name of primitive
* type or array in the same format as returned by the
* java.lang.Class.getName() method.
* @param classLoader the ClassLoader used to load classes
* @return the Class object for the requested className
*
* @throws ClassNotFoundException when the classLoader can not
* find the requested class
*/
public static Class loadClass(String className, ClassLoader classLoader)
throws ClassNotFoundException
{
// ClassLoader.loadClass() does not handle primitive types:
//
// B byte
// C char
// D double
// F float
// I int
// J long
// S short
// Z boolean
// V void
//
if (className.length() == 1)
{
char type = className.charAt(0);
if (type == 'B') return Byte.TYPE;
if (type == 'C') return Character.TYPE;
if (type == 'D') return Double.TYPE;
if (type == 'F') return Float.TYPE;
if (type == 'I') return Integer.TYPE;
if (type == 'J') return Long.TYPE;
if (type == 'S') return Short.TYPE;
if (type == 'Z') return Boolean.TYPE;
if (type == 'V') return Void.TYPE;
// else throw...
throw new ClassNotFoundException(className);
}
// Check for a primative type
if( isPrimitive(className) == true )
return (Class) Classes.PRIMITIVE_NAME_TYPE_MAP.get(className);
// Check for the internal vm format: Lclassname;
if (className.charAt(0) == 'L' && className.charAt(className.length() - 1) == ';')
return classLoader.loadClass(className.substring(1, className.length() - 1));
// first try - be optimistic
// this will succeed for all non-array classes and array classes that have already been resolved
//
try
{
return classLoader.loadClass(className);
}
catch (ClassNotFoundException e)
{
// if it was non-array class then throw it
if (className.charAt(0) != '[')
throw e;
}
// we are now resolving array class for the first time
// count opening braces
int arrayDimension = 0;
while (className.charAt(arrayDimension) == '[')
arrayDimension++;
// resolve component type - use recursion so that we can resolve primitive types also
Class componentType = loadClass(className.substring(arrayDimension), classLoader);
// construct array class
return Array.newInstance(componentType, new int[arrayDimension]).getClass();
}
/**
* Convert a list of Strings from an Interator into an array of
* Classes (the Strings are taken as classnames).
*
* @param it A java.util.Iterator pointing to a Collection of Strings
* @param cl The ClassLoader to use
*
* @return Array of Classes
*
* @throws ClassNotFoundException When a class could not be loaded from
* the specified ClassLoader
*/
public final static Class[] convertToJavaClasses(Iterator it,
ClassLoader cl)
throws ClassNotFoundException
{
ArrayList> classes = new ArrayList>();
while (it.hasNext())
{
classes.add(convertToJavaClass(it.next(), cl));
}
return classes.toArray(new Class[classes.size()]);
}
/**
* Returns attribute's getter method. If the method not found then NoSuchMethodException will be thrown.
* @param cls the class the attribute belongs too
* @param attr the attribute's name
* @return attribute's getter method
* @throws NoSuchMethodException if the getter was not found
*/
public final static Method getAttributeGetter(Class cls, String attr) throws NoSuchMethodException
{
StringBuffer buf = new StringBuffer(attr.length() + 3);
buf.append("get");
if(Character.isLowerCase(attr.charAt(0)))
{
buf.append(Character.toUpperCase(attr.charAt(0)))
.append(attr.substring(1));
}
else
{
buf.append(attr);
}
try
{
return cls.getMethod(buf.toString(), (Class[]) null);
}
catch (NoSuchMethodException e)
{
buf.replace(0, 3, "is");
return cls.getMethod(buf.toString(), (Class[]) null);
}
}
/**
* Returns attribute's setter method. If the method not found then NoSuchMethodException will be thrown.
* @param cls the class the attribute belongs to
* @param attr the attribute's name
* @param type the attribute's type
* @return attribute's setter method
* @throws NoSuchMethodException if the setter was not found
*/
public final static Method getAttributeSetter(Class cls, String attr, Class type) throws NoSuchMethodException
{
StringBuffer buf = new StringBuffer(attr.length() + 3);
buf.append("set");
if(Character.isLowerCase(attr.charAt(0)))
{
buf.append(Character.toUpperCase(attr.charAt(0)))
.append(attr.substring(1));
}
else
{
buf.append(attr);
}
return cls.getMethod(buf.toString(), new Class[]{type});
}
/**
* Convert a given String into the appropriate Class.
*
* @param name Name of class
* @param cl ClassLoader to use
*
* @return The class for the given name
*
* @throws ClassNotFoundException When the class could not be found by
* the specified ClassLoader
*/
private final static Class convertToJavaClass(String name,
ClassLoader cl)
throws ClassNotFoundException
{
int arraySize = 0;
while (name.endsWith("[]"))
{
name = name.substring(0, name.length() - 2);
arraySize++;
}
// Check for a primitive type
Class c = (Class) PRIMITIVE_NAME_TYPE_MAP.get(name);
if (c == null)
{
// No primitive, try to load it from the given ClassLoader
try
{
c = cl.loadClass(name);
}
catch (ClassNotFoundException cnfe)
{
throw new ClassNotFoundException("Parameter class not found: " +
name);
}
}
// if we have an array get the array class
if (arraySize > 0)
{
int[] dims = new int[arraySize];
for (int i = 0; i < arraySize; i++)
{
dims[i] = 1;
}
c = Array.newInstance(c, dims).getClass();
}
return c;
}
/**
* Get a system property
*
* @param name the property name
* @param defaultValue the default value
*/
private static String getProperty(final String name, final String defaultValue)
{
return (String) AccessController.doPrivileged(
new PrivilegedAction()
{
public Object run()
{
return System.getProperty(name, defaultValue);
}
});
}
}