org.asteriskjava.util.ReflectionUtil Maven / Gradle / Ivy
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/*
* Copyright 2005-2006 Stefan Reuter
*
* 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.asteriskjava.util;
import java.io.File;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* Utility class that provides helper methods for reflection that is used by the
* fastagi and manager packages to access getter and setter methods.
*
* Client code is not supposed to use this class.
*
* @author srt
*/
public class ReflectionUtil
{
private ReflectionUtil()
{
// hide constructor
}
/**
* Returns a Map of getter methods of the given class.
*
* The key of the map contains the name of the attribute that can be
* accessed by the getter, the value the getter itself (an instance of
* java.lang.reflect.Method). A method is considered a getter if its name
* starts with "get", it is declared public and takes no arguments.
*
* @param clazz the class to return the getters for
* @return a Map of attributes and their accessor methods (getters)
*/
public static Map getGetters(final Class< ? > clazz)
{
final Map accessors = new HashMap<>();
final Method[] methods = clazz.getMethods();
for (Method method : methods)
{
String name = null;
String methodName = method.getName();
if (methodName.startsWith("get"))
{
name = methodName.substring(3);
}
else if (methodName.startsWith("is"))
{
name = methodName.substring(2);
}
if (name == null || name.length() == 0)
{
continue;
}
// skip methods with != 0 parameters
if (method.getParameterTypes().length != 0)
{
continue;
}
accessors.put(name.toLowerCase(Locale.ENGLISH), method);
}
return accessors;
}
private final static ConcurrentHashMap, Map> setterMap = new ConcurrentHashMap<>();
/**
* The main benefit here is that there will not be repeated errors when
* inspecting classes for setters on every single Event being processed.
*
*
* While this method adds caching which is 100 times faster, the time
* Benefit is largely insignificant as the execution time was already very
* fast.
*
* @param clazz
* @return
*/
public static Map getSetters(Class< ? > clazz)
{
return setterMap.computeIfAbsent(clazz, (c) -> {
return getSettersInternal(c);
});
}
/**
* Returns a Map of setter methods of the given class.
*
* The key of the map contains the name of the attribute that can be
* accessed by the setter, the value the setter itself (an instance of
* java.lang.reflect.Method). A method is considered a setter if its name
* starts with "set", it is declared public and takes exactly one argument.
*
* @param clazz the class to return the setters for
* @return a Map of attributes and their accessor methods (setters)
*/
private static Map getSettersInternal(Class< ? > clazz)
{
final Map accessors = new HashMap<>();
final Method[] methods = clazz.getMethods();
for (Method method : methods)
{
String name;
String methodName = method.getName();
if (!methodName.startsWith("set"))
{
continue;
}
// skip methods with != 1 parameters
if (method.getParameterTypes().length != 1)
{
continue;
}
// OK seems to be an setter
name = methodName.substring("set".length()).toLowerCase(Locale.US);
// if an event class implements a setter that exists in
// ManagerEvent, then prefer the setter from the extending class
Method existing = accessors.get(name);
if (existing != null)
{
logger.warn("multiple setters (case insensitive) exist for " + name + " on class(es) "
+ existing.getDeclaringClass() + " and " + method.getDeclaringClass());
}
if (existing == null)
{
// we don't have a mapping for this setter so add it.
accessors.put(name, method);
}
else if (method.getDeclaringClass().isAssignableFrom(existing.getDeclaringClass()))
{
// we already have a mapping for this setter, but this one is
// from an extending class so replace it.
logger.warn("Preferring setter from extending class " + existing + " -> " + method);
accessors.put(name, method);
}
else
{
// there is already a mapping for this setter from class
logger.warn("Preferring setter from extending class " + method + " -> " + existing);
}
}
return accessors;
}
/**
* Strips all illegal charaters from the given lower case string. Illegal
* characters are all characters that are neither characters ('a' to 'z')
* nor digits ('0' to '9').
*
* @param s the original string
* @return the string with all illegal characters stripped
*/
public static String stripIllegalCharacters(String s)
{
char c;
boolean needsStrip = false;
StringBuilder sb;
if (s == null)
{
return null;
}
for (int i = 0; i < s.length(); i++)
{
c = s.charAt(i);
if (c >= '0' && c <= '9')
{
// continue
} // NOPMD
else if (c >= 'a' && c <= 'z')
{
// continue
} // NOPMD
else
{
needsStrip = true;
break;
}
}
if (!needsStrip)
{
return s;
}
sb = new StringBuilder(s.length());
for (int i = 0; i < s.length(); i++)
{
c = s.charAt(i);
if (c >= '0' && c <= '9')
{
sb.append(c);
}
else if (c >= 'a' && c <= 'z')
{
sb.append(c);
}
}
return sb.toString();
}
/**
* Checks if the class is available on the current thread's context class
* loader.
*
* @param s fully qualified name of the class to check.
* @return true if the class is available, false
* otherwise.
*/
public static boolean isClassAvailable(String s)
{
final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
try
{
classLoader.loadClass(s);
return true;
}
catch (ClassNotFoundException e)
{
return false;
}
}
/**
* Creates a new instance of the given class. The class is loaded using the
* current thread's context class loader and instantiated using its default
* constructor.
*
* @param s fully qualified name of the class to instantiate.
* @return the new instance or null on failure.
*/
public static Object newInstance(String s)
{
final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
try
{
Class< ? > clazz = classLoader.loadClass(s);
Constructor< ? > constructor = clazz.getConstructor();
return constructor.newInstance();
}
catch (ClassNotFoundException e)
{
return null;
}
catch (IllegalAccessException e)
{
return null;
}
catch (InstantiationException e)
{
return null;
}
catch (NoSuchMethodException e)
{
// no default constructor
return null;
}
catch (InvocationTargetException e)
{
// constructor threw an exception
return null;
}
}
private static final Log logger = LogFactory.getLog(ReflectionUtil.class);
/**
* find and all non abstract classes that implement/extend
* baseClassOrInterface in the package packageName
*
* @param packageName
* @param baseClassOrInterface
* @return
*/
@SuppressWarnings("unchecked")
public static Set> loadClasses(String packageName, Class baseClassOrInterface)
{
Set> result = new HashSet<>();
try
{
Set classNames = getClassNamesFromPackage(packageName);
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
for (String className : classNames)
{
try
{
Class< ? > clazz = classLoader.loadClass(packageName + "." + className);
if (!Modifier.isAbstract(clazz.getModifiers()) && baseClassOrInterface.isAssignableFrom(clazz))
{
result.add((Class) clazz);
}
}
catch (Throwable e)
{
logger.error(e, e);
}
}
logger.info("Loaded " + result.size());
}
catch (Exception e)
{
logger.error(e, e);
}
return result;
}
/**
* retrieve all the classes that can be found on the classpath for the
* specified packageName
*
* @param packageName
* @return
* @throws IOException
* @throws URISyntaxException
*/
private static Set getClassNamesFromPackage(String packageName) throws IOException, URISyntaxException
{
ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
Enumeration packageURLs;
Set names = new HashSet();
packageName = packageName.replace(".", "/");
packageURLs = classLoader.getResources(packageName);
while (packageURLs.hasMoreElements())
{
URL packageURL = packageURLs.nextElement();
if (packageURL.getProtocol().equals("jar"))
{
String jarFileName;
Enumeration jarEntries;
String entryName;
// build jar file name, then loop through entries
jarFileName = URLDecoder.decode(packageURL.getFile(), "UTF-8");
jarFileName = jarFileName.substring(5, jarFileName.indexOf("!"));
logger.info(">" + jarFileName);
try (JarFile jf = new JarFile(jarFileName);)
{
jarEntries = jf.entries();
while (jarEntries.hasMoreElements())
{
entryName = jarEntries.nextElement().getName();
if (entryName.startsWith(packageName) && entryName.endsWith(".class"))
{
entryName = entryName.substring(packageName.length() + 1, entryName.lastIndexOf('.'));
names.add(entryName);
}
}
}
// loop through files in classpath
}
else
{
URI uri = new URI(packageURL.toString());
File folder = new File(uri.getPath());
// won't work with path which contains blank (%20)
// File folder = new File(packageURL.getFile());
File[] files = folder.listFiles();
if (files != null)
{
for (File actual : files)
{
String entryName = actual.getName();
entryName = entryName.substring(0, entryName.lastIndexOf('.'));
names.add(entryName);
}
}
}
}
// clean up
Iterator itr = names.iterator();
while (itr.hasNext())
{
String name = itr.next();
if (name.equals("package") || name.endsWith(".") || name.length() == 0)
{
itr.remove();
}
}
return names;
}
}