Mega Code Archive
Several utility functions for the JMX implementation
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/*
* Copyright (C) The MX4J Contributors.
* All rights reserved.
*
* This software is distributed under the terms of the MX4J License version 1.0.
* See the terms of the MX4J License in the documentation provided with this software.
*/
import java.lang.reflect.Array;
import java.lang.reflect.Method;
/**
* Several utility functions for the JMX implementation
*
* @version $Revision: 1.18 $
*/
public class Utils
{
/**
* This methods load a class given the classloader and the name of the class, and work for
* extended names of primitive types. <p>
* If you try to do ClassLoader.loadClass("boolean") it barfs it cannot find the class,
* so this method cope with this problem.
*/
public static Class loadClass(ClassLoader loader, String name) throws ClassNotFoundException
{
if (name == null) throw new ClassNotFoundException("null");
name = name.trim();
if (name.equals("boolean"))
return boolean.class;
else if (name.equals("byte"))
return byte.class;
else if (name.equals("char"))
return char.class;
else if (name.equals("short"))
return short.class;
else if (name.equals("int"))
return int.class;
else if (name.equals("long"))
return long.class;
else if (name.equals("float"))
return float.class;
else if (name.equals("double"))
return double.class;
else if (name.equals("java.lang.String"))
return String.class;
else if (name.equals("java.lang.Object"))
return Object.class;
else if (name.startsWith("["))
{
// It's an array, figure out how many dimensions
int dimension = 0;
while (name.charAt(dimension) == '[')
{
++dimension;
}
char type = name.charAt(dimension);
Class cls = null;
switch (type)
{
case 'Z':
cls = boolean.class;
break;
case 'B':
cls = byte.class;
break;
case 'C':
cls = char.class;
break;
case 'S':
cls = short.class;
break;
case 'I':
cls = int.class;
break;
case 'J':
cls = long.class;
break;
case 'F':
cls = float.class;
break;
case 'D':
cls = double.class;
break;
case 'L':
// Strip the semicolon at the end
String n = name.substring(dimension + 1, name.length() - 1);
cls = loadClass(loader, n);
break;
}
if (cls == null)
{
throw new ClassNotFoundException(name);
}
else
{
int[] dim = new int[dimension];
return Array.newInstance(cls, dim).getClass();
}
}
else
{
if (loader != null)
return loader.loadClass(name);
else
return Class.forName(name, false, null);
}
}
/**
* Returns the classes whose names are specified by the <code>names</code> argument, loaded with the
* specified classloader.
*/
public static Class[] loadClasses(ClassLoader loader, String[] names) throws ClassNotFoundException
{
int n = names.length;
Class[] cls = new Class[n];
for (int i = 0; i < n; ++i)
{
String name = names[i];
cls[i] = loadClass(loader, name);
}
return cls;
}
/**
* Returns true is the given method is a JMX attribute getter method
*/
public static boolean isAttributeGetter(Method m)
{
if (m == null) return false;
String name = m.getName();
Class retType = m.getReturnType();
Class[] params = m.getParameterTypes();
if (retType != Void.TYPE && params.length == 0)
{
if (name.startsWith("get") && name.length() > 3)
return true;
else if (name.startsWith("is") && name.length() > 2 && retType == Boolean.TYPE) return true;
}
return false;
}
/**
* Returns true if the method is a JMX attribute setter method
*/
public static boolean isAttributeSetter(Method m)
{
if (m == null) return false;
String name = m.getName();
Class retType = m.getReturnType();
Class[] params = m.getParameterTypes();
if (retType == Void.TYPE && params.length == 1 && name.startsWith("set") && name.length() > 3)
{
return true;
}
return false;
}
public static boolean wildcardMatch(String pattern, String string)
{
int stringLength = string.length();
int stringIndex = 0;
for (int patternIndex = 0; patternIndex < pattern.length(); ++patternIndex)
{
char c = pattern.charAt(patternIndex);
if (c == '*')
{
// Recurse with the pattern without this '*' and the actual string, until
// match is found or we inspected the whole string
while (stringIndex < stringLength)
{
if (wildcardMatch(pattern.substring(patternIndex + 1), string.substring(stringIndex)))
{
return true;
}
// No match found, try a shorter string, since we are matching '*'
++stringIndex;
}
}
else if (c == '?')
{
// Increment the string index, since '?' match a single char in the string
++stringIndex;
if (stringIndex > stringLength)
{
return false;
}
}
else
{
// A normal character in the pattern, must match the one in the string
if (stringIndex >= stringLength || c != string.charAt(stringIndex))
{
return false;
}
++stringIndex;
}
}
// I've inspected the whole pattern, but not the whole string
return stringIndex == stringLength;
}
public static boolean arrayEquals(Object[] arr1, Object[] arr2)
{
if (arr1 == null && arr2 == null) return true;
if (arr1 == null ^ arr2 == null) return false;
if (!arr1.getClass().equals(arr2.getClass())) return false;
if (arr1.length != arr2.length) return false;
for (int i = 0; i < arr1.length; ++i)
{
Object obj1 = arr1[i];
Object obj2 = arr2[i];
if (obj1 == null ^ obj2 == null) return false;
if (obj1 != null && !obj1.equals(obj2)) return false;
}
return true;
}
public static boolean arrayEquals(byte[] arr1, byte[] arr2)
{
if (arr1 == null && arr2 == null) return true;
if (arr1 == null ^ arr2 == null) return false;
if (!arr1.getClass().equals(arr2.getClass())) return false;
if (arr1.length != arr2.length) return false;
for (int i = 0; i < arr1.length; ++i)
{
byte b1 = arr1[i];
byte b2 = arr2[i];
if (b1 != b2) return false;
}
return true;
}
public static int arrayHashCode(Object[] arr)
{
int hash = 0;
if (arr != null)
{
// Avoid that 2 arrays of length 0 but different classes return same hash
hash ^= arr.getClass().hashCode();
for (int i = 0; i < arr.length; ++i)
{
hash ^= arr[i] == null ? 0 : arr[i].hashCode();
}
}
return hash;
}
public static int arrayHashCode(byte[] arr)
{
int hash = 0;
if (arr != null)
{
// Avoid that 2 arrays of length 0 but different classes return same hash
hash ^= arr.getClass().hashCode();
for (int i = 0; i < arr.length; ++i)
{
hash ^= arr[i];
}
}
return hash;
}
public static char[] arrayCopy(char[] chars)
{
if (chars == null) return null;
char[] copy = new char[chars.length];
System.arraycopy(chars, 0, copy, 0, chars.length);
return copy;
}
}
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