Tomcat example source code file (ReflectionUtil.java)

This example Tomcat source code file (ReflectionUtil.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

bean, class, class, classnotfoundexception, elexception, javabean, method, object, object, primitives, propertydescriptor, propertydescriptor, reflection, reflectionutil, string, string, stringbuffer, util

The Tomcat ReflectionUtil.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.el.util;

import java.beans.IntrospectionException;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.util.Arrays;

import javax.el.ELException;
import javax.el.MethodNotFoundException;
import javax.el.PropertyNotFoundException;

import org.apache.el.lang.ELSupport;


/**
 * Utilities for Managing Serialization and Reflection
 * 
 * @author Jacob Hookom [jacob@hookom.net]
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: markt $
 */
public class ReflectionUtil {

    protected static final String[] EMPTY_STRING = new String[0];

    protected static final String[] PRIMITIVE_NAMES = new String[] { "boolean",
            "byte", "char", "double", "float", "int", "long", "short", "void" };

    protected static final Class[] PRIMITIVES = new Class[] { boolean.class,
            byte.class, char.class, double.class, float.class, int.class,
            long.class, short.class, Void.TYPE };

    /**
     * 
     */
    private ReflectionUtil() {
        super();
    }

    public static Class forName(String name) throws ClassNotFoundException {
        if (null == name || "".equals(name)) {
            return null;
        }
        Class c = forNamePrimitive(name);
        if (c == null) {
            if (name.endsWith("[]")) {
                String nc = name.substring(0, name.length() - 2);
                c = Class.forName(nc, true, Thread.currentThread().getContextClassLoader());
                c = Array.newInstance(c, 0).getClass();
            } else {
                c = Class.forName(name, true, Thread.currentThread().getContextClassLoader());
            }
        }
        return c;
    }

    protected static Class forNamePrimitive(String name) {
        if (name.length() <= 8) {
            int p = Arrays.binarySearch(PRIMITIVE_NAMES, name);
            if (p >= 0) {
                return PRIMITIVES[p];
            }
        }
        return null;
    }

    /**
     * Converts an array of Class names to Class types
     * @param s
     * @return
     * @throws ClassNotFoundException
     */
    public static Class[] toTypeArray(String[] s) throws ClassNotFoundException {
        if (s == null)
            return null;
        Class[] c = new Class[s.length];
        for (int i = 0; i < s.length; i++) {
            c[i] = forName(s[i]);
        }
        return c;
    }

    /**
     * Converts an array of Class types to Class names
     * @param c
     * @return
     */
    public static String[] toTypeNameArray(Class[] c) {
        if (c == null)
            return null;
        String[] s = new String[c.length];
        for (int i = 0; i < c.length; i++) {
            s[i] = c[i].getName();
        }
        return s;
    }

    /**
     * Returns a method based on the criteria
     * @param base the object that owns the method
     * @param property the name of the method
     * @param paramTypes the parameter types to use
     * @return the method specified
     * @throws MethodNotFoundException
     */
    public static Method getMethod(Object base, Object property,
            Class[] paramTypes) throws MethodNotFoundException {
        if (base == null || property == null) {
            throw new MethodNotFoundException(MessageFactory.get(
                    "error.method.notfound", base, property,
                    paramString(paramTypes)));
        }

        String methodName = (property instanceof String) ? (String) property
                : property.toString();

        Method method = null;
        try {
            method = base.getClass().getMethod(methodName, paramTypes);
        } catch (NoSuchMethodException nsme) {
            throw new MethodNotFoundException(MessageFactory.get(
                    "error.method.notfound", base, property,
                    paramString(paramTypes)));
        }
        return method;
    }

    protected static final String paramString(Class[] types) {
        if (types != null) {
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < types.length; i++) {
                sb.append(types[i].getName()).append(", ");
            }
            if (sb.length() > 2) {
                sb.setLength(sb.length() - 2);
            }
            return sb.toString();
        }
        return null;
    }

    /**
     * @param base
     * @param property
     * @return
     * @throws ELException
     * @throws PropertyNotFoundException
     */
    public static PropertyDescriptor getPropertyDescriptor(Object base,
            Object property) throws ELException, PropertyNotFoundException {
        String name = ELSupport.coerceToString(property);
        PropertyDescriptor p = null;
        try {
            PropertyDescriptor[] desc = Introspector.getBeanInfo(
                    base.getClass()).getPropertyDescriptors();
            for (int i = 0; i < desc.length; i++) {
                if (desc[i].getName().equals(name)) {
                    return desc[i];
                }
            }
        } catch (IntrospectionException ie) {
            throw new ELException(ie);
        }
        throw new PropertyNotFoundException(MessageFactory.get(
                "error.property.notfound", base, name));
    }
}