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

Home
Java
1.2D Graphics GUI
2.3D
3.Advanced Graphics
4.Ant
5.Apache Common
6.Chart
7.Class
8.Collections Data Structure
9.Data Type
10.Database SQL JDBC
11.Design Pattern
12.Development Class
13.EJB3
14.Email
15.Event
16.File Input Output
17.Game
18.Generics
19.GWT
20.Hibernate
21.I18N
22.J2EE
23.J2ME
24.JDK 6
25.JNDI LDAP
26.JPA
27.JSP
28.JSTL
29.Language Basics
30.Network Protocol
31.PDF RTF
32.Reflection
33.Regular Expressions
34.Scripting
35.Security
36.Servlets
37.Spring
38.Swing Components
39.Swing JFC
40.SWT JFace Eclipse
41.Threads
42.Tiny Application
43.Velocity
44.Web Services SOA
45.XML
Java » Reflection » ClassScreenshots 
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;
  }

}

   
    
    
    
    
    
  
Related examples in the same category
1.Class Reflection: class modifierClass Reflection: class modifier
2.Class Reflection: class nameClass Reflection: class name
3.Class Reflection: name for super classClass Reflection: name for super class
4.Object Reflection: create new instance
5.Class reflectionClass reflection
6.This class shows using Reflection to get a field from another classThis class shows using Reflection to get a field from another class
7.Show the class keyword and getClass() method in actionShow the class keyword and getClass() method in action
8.Simple Demonstration of a ClassLoader WILL NOT COMPILE OUT OF THE BOX
9.Demonstrate classFor to create an instance of an object
10.CrossRef prints a cross-reference about all classes named in argv
11.Make up a compilable version of a given Sun or other API
12.Show a couple of things you can do with a Class object
13.Reflect1 shows the information about the class named in argv
14.Show that you can, in fact, take the class of a primitive
15.JavaP prints structural information about classes
16.Provides a set of static methods that extend the Java metaobject
17.Demonstration of speed of reflexive versus programmatic invocation
18.Use reflection to get console char set
19.Load the class source location from Class.getResource()
20.Access the enclosing class from an inner class
21.Use reflection to dynamically discover the capabilities of a class.
22.Get the class By way of a string
23.Get the class By way of .class
24.Return a String representation of an object's overall identity
25.Manipulate Java class files in strange and mysterious ways
26.Class file reader for obtaining the parameter names for declared methods in a class
27.Manipulate Java classes
28.Encapsulates a class serialVersionUID and codebase.
29.Dump a class using Reflection
30.This program uses reflection to spy on objects
31.This program uses reflection to print all features of a classThis program uses reflection to print all features of a class
32.Get Unqualified Name
33.Return a paranthesis enclosed, comma sepearated String of all SimpleClass names in params.
34.Adds the class SimpleNames, comma sepearated and surrounded by paranthesis to the call StringBuffer
35.Class Finder
java2s.com  | Contact Us | Privacy Policy
Copyright 2009 - 12 Demo Source and Support. All rights reserved.
All other trademarks are property of their respective owners.