/*
* JBoss, Home of Professional Open Source.
*
* See the LEGAL.txt file distributed with this work for information regarding copyright ownership and licensing.
*
* See the AUTHORS.txt file distributed with this work for a full listing of individual contributors.
*/
package org.teiid.core.designer.util;
import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import org.teiid.core.designer.CoreModelerPlugin;
import org.teiid.core.designer.TeiidDesignerException;
/**
* @since 8.0
*/
public class ReflectionHelper {
private Class<?> targetClass;
private Map<String, LinkedList<Method>> methodMap = null; // used for the brute-force method finder
/**
* Construct a ReflectionHelper instance that cache's some information about
* the target class. The target class is the Class object upon which the
* methods will be found.
* @param targetClass the target class
* @throws IllegalArgumentException if the target class is null
*/
public ReflectionHelper( Class<?> targetClass ) {
if ( targetClass == null ) {
throw new IllegalArgumentException(CoreModelerPlugin.Util.getString("ReflectionHelper.errorConstructing")); //$NON-NLS-1$
}
this.targetClass = targetClass;
}
/**
* Find the best method on the target class that matches the signature specified
* with the specified name and the list of arguments. This method first
* attempts to find the method with the specified arguments; if no such
* method is found, a NoSuchMethodException is thrown.
* <P>
* This method is unable to find methods with signatures that include both
* primitive arguments <i>and</i> arguments that are instances of <code>Number</code>
* or its subclasses.
* @param methodName the name of the method that is to be invoked.
* @param arguments the array of Object instances that correspond
* to the arguments passed to the method.
* @return the Method object that references the method that satisfies
* the requirements, or null if no satisfactory method could be found.
* @throws NoSuchMethodException if a matching method is not found.
* @throws SecurityException if access to the information is denied.
*/
public Method findBestMethodOnTarget( String methodName, Object[] arguments ) throws NoSuchMethodException, SecurityException {
if (arguments == null) {
return findBestMethodWithSignature(methodName, Collections.EMPTY_LIST);
}
int size = arguments.length;
List<Class<?>> argumentClasses = new ArrayList<Class<?>>(size);
for (int i=0; i!=size; ++i) {
if ( arguments[i] != null ) {
Class<?> clazz = arguments[i].getClass();
argumentClasses.add( clazz );
} else {
argumentClasses.add(null);
}
}
return findBestMethodWithSignature(methodName,argumentClasses);
}
/**
* Find the best method on the target class that matches the signature specified
* with the specified name and the list of argument classes. This method first
* attempts to find the method with the specified argument classes; if no such
* method is found, a NoSuchMethodException is thrown.
* @param methodName the name of the method that is to be invoked.
* @param argumentsClasses the list of Class instances that correspond
* to the classes for each argument passed to the method.
* @return the Method object that references the method that satisfies
* the requirements, or null if no satisfactory method could be found.
* @throws NoSuchMethodException if a matching method is not found.
* @throws SecurityException if access to the information is denied.
*/
public Method findBestMethodWithSignature( String methodName, Object[] argumentsClasses ) throws NoSuchMethodException, SecurityException {
List argumentClassesList = Arrays.asList(argumentsClasses);
return findBestMethodWithSignature(methodName,argumentClassesList);
}
/**
* Find the best method on the target class that matches the signature specified
* with the specified name and the list of argument classes. This method first
* attempts to find the method with the specified argument classes; if no such
* method is found, a NoSuchMethodException is thrown.
* @param methodName the name of the method that is to be invoked.
* @param argumentsClasses the list of Class instances that correspond
* to the classes for each argument passed to the method.
* @return the Method object that references the method that satisfies
* the requirements, or null if no satisfactory method could be found.
* @throws NoSuchMethodException if a matching method is not found.
* @throws SecurityException if access to the information is denied.
*/
public Method findBestMethodWithSignature( String methodName, List<Class<?>> argumentsClasses ) throws NoSuchMethodException, SecurityException {
// Attempt to find the method
Method result = null;
Class[] classArgs = new Class[argumentsClasses.size()];
// -------------------------------------------------------------------------------
// First try to find the method with EXACTLY the argument classes as specified ...
// -------------------------------------------------------------------------------
try {
argumentsClasses.toArray(classArgs);
result = this.targetClass.getMethod(methodName,classArgs); // this may throw an exception if not found
return result;
} catch ( NoSuchMethodException e ) {
// No method found, so continue ...
}
// ---------------------------------------------------------------------------------------------
// Then try to find a method with the argument classes converted to a primitive, if possible ...
// ---------------------------------------------------------------------------------------------
List<Class<?>> argumentsClassList = convertArgumentClassesToPrimitives(argumentsClasses);
argumentsClassList.toArray(classArgs);
try {
result = this.targetClass.getMethod(methodName,classArgs); // this may throw an exception if not found
return result;
} catch ( NoSuchMethodException e ) {
// No method found, so continue ...
}
// ---------------------------------------------------------------------------------------------
// Still haven't found anything. So far, the "getMethod" logic only finds methods that EXACTLY
// match the argument classes (i.e., not methods declared with superclasses or interfaces of
// the arguments). There is no canned algorithm in Java to do this, so we have to brute-force it.
// ---------------------------------------------------------------------------------------------
if ( this.methodMap == null ) {
this.methodMap = new HashMap<String, LinkedList<Method>>();
Method[] methods = this.targetClass.getMethods();
for ( int i=0; i!=methods.length; ++i ) {
Method method = methods[i];
LinkedList<Method> methodsWithSameName = this.methodMap.get(method.getName());
if ( methodsWithSameName == null ) {
methodsWithSameName = new LinkedList<Method>();
this.methodMap.put(method.getName(),methodsWithSameName);
}
methodsWithSameName.addFirst(method); // add lower methods first
}
}
LinkedList<Method> methodsWithSameName = this.methodMap.get(methodName);
if ( methodsWithSameName == null ) {
throw new NoSuchMethodException(methodName);
}
for (Method method : methodsWithSameName) {
Class[] args = method.getParameterTypes();
boolean allMatch = argsMatch(argumentsClasses, argumentsClassList, args);
if ( allMatch ) {
if (result != null) {
throw new NoSuchMethodException(methodName + " Args: " + argumentsClasses + " has multiple possible signatures."); //$NON-NLS-1$ //$NON-NLS-2$
}
result = method;
}
}
if (result != null) {
return result;
}
throw new NoSuchMethodException(methodName + " Args: " + argumentsClasses); //$NON-NLS-1$
}
private static boolean argsMatch(List<Class<?>> argumentsClasses,
List<Class<?>> argumentsClassList, Class[] args) {
if ( args.length != argumentsClasses.size() ) {
return false;
}
for ( int i=0; i<args.length; ++i ) {
Class<?> primitiveClazz = argumentsClassList.get(i);
Class<?> objectClazz = argumentsClasses.get(i);
if ( objectClazz != null ) {
// Check for possible matches with (converted) primitive types
// as well as the original Object type
if ( ! args[i].equals(primitiveClazz) && ! args[i].isAssignableFrom(objectClazz) ) {
return false; // found one that doesn't match
}
} else {
// a null is assignable for everything except a primitive
if ( args[i].isPrimitive() ) {
return false; // found one that doesn't match
}
}
}
return true;
}
/**
* Convert any argument classes to primitives.
* @param arguments the list of argument classes.
* @return the list of Class instances in which any classes that could be represented
* by primitives (e.g., Boolean) were replaced with the primitive classes (e.g., Boolean.TYPE).
*/
private static List<Class<?>> convertArgumentClassesToPrimitives( List<Class<?>> arguments ) {
List<Class<?>> result = new ArrayList<Class<?>>(arguments.size());
for (Class<?> clazz : arguments) {
if ( clazz == Boolean.class ) clazz = Boolean.TYPE;
else if ( clazz == Character.class ) clazz = Character.TYPE;
else if ( clazz == Byte.class ) clazz = Byte.TYPE;
else if ( clazz == Short.class ) clazz = Short.TYPE;
else if ( clazz == Integer.class ) clazz = Integer.TYPE;
else if ( clazz == Long.class ) clazz = Long.TYPE;
else if ( clazz == Float.class ) clazz = Float.TYPE;
else if ( clazz == Double.class ) clazz = Double.TYPE;
else if ( clazz == Void.class ) clazz = Void.TYPE;
result.add( clazz );
}
return result;
}
/**
* Helper method to load a class.
* @param className is the class to instantiate
* @param classLoader the class loader to use; may be null if the current
* class loader is to be used
* @return Class is the instance of the class
* @throws ClassNotFoundException
*/
private static final Class<?> loadClass(final String className, final ClassLoader classLoader) throws ClassNotFoundException {
Class<?> cls = null;
if ( classLoader == null ) {
cls = Class.forName(className.trim());
} else {
cls = Class.forName(className.trim(),true,classLoader);
}
return cls;
}
/**
* Helper method to create an instance of the class using the appropriate
* constructor based on the ctorObjs passed.
* @param className is the class to instantiate
* @param ctorObjs are the objects to pass to the constructor; optional, nullable
* @param classLoader the class loader to use; may be null if the current
* class loader is to be used
* @return Object is the instance of the class
* @throws TeiidDesignerException if an error occurs instantiating the class
*/
public static final Object create(String className, Collection<?> ctorObjs,
final ClassLoader classLoader) throws TeiidDesignerException {
try {
int size = (ctorObjs == null ? 0 : ctorObjs.size());
Class[] names = new Class[size];
Object[] objArray = new Object[size];
int i = 0;
if (size > 0) {
for (Iterator<?> it=ctorObjs.iterator(); it.hasNext(); ) {
Object obj = it.next();
if (obj != null) {
names[i] = obj.getClass();
objArray[i] = obj;
}
i++;
}
}
return create(className, objArray, names, classLoader);
} catch (Exception e) {
throw new TeiidDesignerException(e);
}
}
public static final Object create(String className, Object[] ctorObjs, Class<?>[] argTypes,
final ClassLoader classLoader) throws TeiidDesignerException {
Class<?> cls;
try {
cls = loadClass(className,classLoader);
} catch(Exception e) {
throw new TeiidDesignerException(e);
}
Constructor<?> ctor = null;
try {
ctor = cls.getDeclaredConstructor(argTypes);
} catch (NoSuchMethodException e) {
}
if (ctor == null && argTypes != null && argTypes.length > 0) {
List<Class<?>> argumentsClasses = Arrays.asList(argTypes);
List<Class<?>> argumentsClassList = convertArgumentClassesToPrimitives(argumentsClasses);
for (Constructor<?> possible : cls.getDeclaredConstructors()) {
if (argsMatch(argumentsClasses, argumentsClassList, possible.getParameterTypes())) {
ctor = possible;
break;
}
}
}
if (ctor == null) {
throw new TeiidDesignerException(className + " " + Arrays.toString(argTypes)); //$NON-NLS-1$
}
try {
return ctor.newInstance(ctorObjs);
} catch (Exception e) {
throw new TeiidDesignerException(e);
}
}
}