Android Open Source - Resonos-Android-Framework Parameter List

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License

The source code is released under:

Apache License

Java Source Code

package com.resonos.apps.library.util;
// w  w  w.ja v a2  s.c  o m
import java.lang.reflect.Method;

/**
 * This class allows the use of any enum to serve as a parameter list (representing booleans only).
 * Simply use any enum as the type.
 * @author Chris
 *
 * @param <T>
 */
public class ParameterList<T extends Enum<?>> {
  private boolean[] _hasParam = null;
  
  /**
   * Construct the parameter list using an array of your chosen enum.
   * This allows you to generate a class that accepts any number of parameters
   * in its constructor or another initialization function as follows:
   *     public Object(Param... params) {
   *       ParameterList<Param> mParams = new ParameterList<Param>(params);
   *     }
   * @param list, the array of parameters
   */
  @SuppressWarnings("unchecked")
  public ParameterList(T[] list) {
    if (list == null)
      return;
    Class<T> cl = (Class<T>) list.getClass().getComponentType();
    T[] av = (T[]) callPrivateStaticMethod(cl, "values");
    _hasParam = new boolean[av.length];
    for (int i = 0; i < _hasParam.length; i++) {
      _hasParam[i] = false;
      for (int j = 0; j < list.length; j++) {
        if (list[j] == av[i]) {
          _hasParam[i] = true;
          break;
        }
      }
    }
  }

  /**
   * Calls a static method, ignoring access checks
   * @param Class
   * @param Method name
   * @return Method return value
   */
  private Object callPrivateStaticMethod(Class<?> cl, String n) {
    try {
      Method m = cl.getDeclaredMethod(n);
      m.setAccessible(true);
      return m.invoke(null, (Object[]) null );
    } catch (Exception e) {
            return null;
    }
  }
  
  /**
   * Determine whether a parameter was given.
   * @param The parameter (use an enum constant)
   * @return true if the parameter was passed
   */
  public boolean has(T t) {
    if (_hasParam == null)
      return false;
    int i = t.ordinal();
    return (i >= 0 && i < _hasParam.length) ? _hasParam[i] : false;
  }
  
  /**
   * Change a parameter value after initialization.
   * @param The parameter (use an enum constant)
   * @param the new boolean value
   */
  @SuppressWarnings("unchecked")
  public void set(T t, boolean b) {
    if (_hasParam == null) { // if this was constructed with a null, we need to set up the param list
      Class<T> cl = (Class<T>)t.getClass();
      T[] av = (T[]) callPrivateStaticMethod(cl, "values");
      _hasParam = new boolean[av.length];
      for (int i = 0; i < _hasParam.length; i++) {
        _hasParam[i] = false;
        if (t == av[i])
          _hasParam[i] = true;
      }
    }
    int i = t.ordinal();
    if (i >= 0 && i < _hasParam.length)
      _hasParam[i] = b;
  }
}

Java Source Code List

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