CollectionDealer.java :  » Web-Framework » vraptor » org » vraptor » reflection » Java Open Source

package org.vraptor.reflection;

import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.util.Collection;
import java.util.Iterator;

import org.vraptor.component.ComponentInstantiationException;

/**
 * Collection implementation.
 * 
 * @author Guilherme Silveira
 */
public class CollectionDealer implements SetDealer {

  @SuppressWarnings("unchecked")
  public Object resizeAndSet(Object object, int position, boolean mayCreate,
      Type type) throws SettingException {
    int length = position + 1;

    Collection collection = (Collection) object;
    int realLen = collection.size();

    if (realLen >= length) {
      return object;
    }

    if ((!mayCreate) || length != realLen + 1) {
      throw new SettingException(
          "Invalid array index - probably missed one object in between: "
              + length);
    }

    Class desiredClass = (type instanceof ParameterizedType) ? (Class) ((ParameterizedType) type)
        .getActualTypeArguments()[0]
        : Object.class;

    try {
      collection.add(ReflectionUtil.instantiate(desiredClass));
    } catch (ComponentInstantiationException e) {
      throw new SettingException(e.getMessage(), e);
    }
    return object;

  }

  public Object getPosition(Object object, int arrayPosition,
      boolean mayCreate) throws SettingException {
    Collection collection = (Collection) object;
    if (arrayPosition >= collection.size()) {
      throw new SettingException("Invalid collection index: "
          + arrayPosition);
    }
    return iterate((Collection) object, arrayPosition);
  }

  /**
   * Iterates over a collection n times
   * 
   * @param collection
   *            the collection
   * @param index
   *            n
   * @return the object at this position
   */
  Object iterate(Collection set, int index) {
    Iterator it = set.iterator();
    for (int i = 0; i < index; i++, it.next()) {
      ;
    }
    return it.next();
  }

  @SuppressWarnings("unchecked")
  public Object resizeAndSet(Object obj, int position, Object value)
      throws SettingException {
    Collection collection = (Collection) obj;
    if (collection.size() > position) {
      throw new SettingException(
          "There is already an object in this position!");
    }
    if (collection.size() != position) {
      throw new SettingException(
          "Invalid array index - probably missed one object in between: "
              + position);
    }
    collection.add(value);
    return obj;
  }

  public Class getType(Type type) {
    return (Class) ((ParameterizedType) type).getActualTypeArguments()[0];
  }

}