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The Apache Commons Codec package contains simple encoder and decoders for various formats such as Base64 and Hexadecimal. In addition to these widely used encoders and decoders, the codec package also maintains a collection of phonetic encoding utilities.
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/*   Copyright 2004 The Apache Software Foundation
 *
 *   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.apache.xmlbeans.impl.jam;

import java.lang.reflect.Constructor;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Arrays;
import java.util.Comparator;

/**
 * Singleton collection of utility methods which can be very useful in
 * some samples, but not often enough to warrant inclusion in the main
 * APIs.  
 *
 * Most of these are here to help you jump from the JClass
 * hierarchy to the java.lang.reflect hierarchy.  This is primarily
 * useful when you find yourself, for example, wanting to actually invoke
 * a method represented by a JMethod.
 *
 * @author Patrick Calahan <email: pcal-at-bea-dot-com>
 */
public class JamUtils {

  // ========================================================================
  // Singleton

  public static final JamUtils getInstance() { return INSTANCE; }

  private JamUtils() {}

  private static final JamUtils INSTANCE = new JamUtils();


  // ========================================================================
  // Public methods

  /**
   * Returns the java.lang.Method on a given
   * java.lang.Class which is represented by a given JMethod.
   *
   * @param containedin Class to be searched for the method.
   * @return
   * @throws ClassNotFoundException if one of the paramType classes specified
   * for this MethodName cannot be loaded from the given class' classloader.
   * @throws NoSuchMethodException If the named method does not exist on
   * this class.
   * @throws IllegalArgumentException if any argument is null
   */
  public Method getMethodOn(JMethod method, Class containedin)
    throws NoSuchMethodException, ClassNotFoundException
  {
    if (containedin == null) throw new IllegalArgumentException("null class");
    if (method == null) throw new IllegalArgumentException("null method");
    Class[] types = null;
    JParameter[] params = method.getParameters();
    if (params != null && params.length > 0) {
      types = new Class[params.length];
      for (int i = 0; i < types.length; i++) {
        types[i] = loadClass(params[i].getType(),containedin.getClassLoader());
      }
    }
    return containedin.getMethod(method.getSimpleName(), types);
  }

  /**
   * Returns the java.lang.Method on a given
   * java.lang.Class which is represented by a given JMethod.
   *
   * @param containedin Class to be searched for the ctor.
   * @return
   * @throws ClassNotFoundException if one of the paramType classes specified
   * for this MethodName cannot be loaded from the given class' classloader.
   * @throws NoSuchMethodException If the named ctor does not exist on
   * this class.
   * @throws IllegalArgumentException if any argument is null
   */
  public Constructor getConstructorOn(JConstructor ctor, Class containedin)
    throws NoSuchMethodException, ClassNotFoundException
  {
    if (containedin == null) throw new IllegalArgumentException("null class");
    if (ctor == null) throw new IllegalArgumentException("null ctor");
    Class[] types = null;
    JParameter[] params = ctor.getParameters();
    if (params != null && params.length > 0) {
      types = new Class[params.length];
      for (int i = 0; i < types.length; i++) {
        types[i] = loadClass(params[i].getType(),containedin.getClassLoader());
      }
    }
    return containedin.getConstructor(types);
  }

  /**
   * Returns the java.lang.Method on a given
   * java.lang.Class which is represented by a given JMethod.
   *
   * @param containedin Class to be searched for the method.
   * @return
   * @throws NoSuchFieldException if the field does not exist on the class.
   * @throws IllegalArgumentException if any argument is null
   */
  public Field getFieldOn(JField field, Class containedin)
    throws NoSuchFieldException
  {
    if (containedin == null) throw new IllegalArgumentException("null class");
    if (field == null) throw new IllegalArgumentException("null field");
    return containedin.getField(field.getSimpleName());
  }


  /**
   * Loads the java.lang.Class represented by a given JClass out of a given
   * classloader.
   * @return
   * @throws ClassNotFoundException If the class is not found in the classloader
   */
  public Class loadClass(JClass clazz, ClassLoader inThisClassloader)
    throws ClassNotFoundException
  {
    return inThisClassloader.loadClass(clazz.getQualifiedName());
  }

  /**
   * Sorts the given array in place so that the elements are ordered by
   * their sourcePosition's line numbers.
   */
  public void placeInSourceOrder(JElement[] elements) {
    if (elements == null) throw new IllegalArgumentException("null elements");
    Arrays.sort(elements,SOURCE_POSITION_COMPARATOR);
  }

  // ========================================================================
  // Private

  private static Comparator SOURCE_POSITION_COMPARATOR = new Comparator() {

    public int compare(Object o, Object o1) {
      JSourcePosition p1 = ((JElement)o).getSourcePosition();
      JSourcePosition p2 = ((JElement)o1).getSourcePosition();
      if (p1 == null) return (p2 == null) ? 0 : -1;
      if (p2 == null) return 1;
      return (p1.getLine() < p2.getLine()) ? -1 :
        (p1.getLine() > p2.getLine()) ? 1 : 0;
    }
  };


}