Convert a given String into the appropriate Class. : Class « Reflection « Java

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Java » Reflection » Class 




Convert a given String into the appropriate Class.
      
import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.StringTokenizer;

/*
 * 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.
 */

public class Main {

  /** 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);
  }
  /**
   * 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<String> it, ClassLoader cl)
      throws ClassNotFoundException {
    ArrayList<Class<?>> classes = new ArrayList<Class<?>>();
    while (it.hasNext()) {
      classes.add(convertToJavaClass(it.next(), cl));
    }
    return classes.toArray(new Class[classes.size()]);
  }

  /**
   * 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 = (ClassPRIMITIVE_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[i1;
      }
      c = Array.newInstance(c, dims).getClass();
    }

    return c;
  }

}

   
    
    
    
    
    
  














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