makeiterator.java

webwork source

package webwork.util;

import java.lang.reflect.Array;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Enumeration;
import java.util.Iterator;
import java.util.Map;

public class MakeIterator {

	public static Iterator convert(Object value) {
		
		Iterator iterator;
		
         if(value instanceof Map)
         {
            value = ((Map)value).entrySet();
         }

         if(value instanceof Collection)
         {
            iterator = ((Collection)value).iterator();
         }
         else if(value.getClass().isArray())
         {
            //need ability to support primitives; therefore, cannot
            //use Object[] casting.
            Object a = Array.newInstance(value.getClass().getComponentType(), (Array.getLength(value)));
            ArrayList list = new ArrayList(Array.getLength(value));
            for(int j = 0; j < Array.getLength(value); j++) {
               list.add(Array.get(value, j));
            }
            iterator = list.iterator();
         }
         else if(value instanceof Enumeration)
         {
            Enumeration enum = (Enumeration)value;
            ArrayList list = new ArrayList();
            while(enum.hasMoreElements())
            {
               list.add(enum.nextElement());
            }
            iterator = list.iterator();
         }
         else
         {
            iterator = (Iterator)value;
         }
		 return iterator;
	}
        
        /**
         * Determine whether a given object can be made into an <code>Iterator</code>
         * @param object the object to check
         * @return <code>true</code> if the object can be converted to an iterator and
         * <code>false</code> otherwise
         */
        public static boolean isIterable(Object object) {
            if (object == null) {
                return false;
            }
            if (object instanceof Map) {
                return true;
            } else if (object instanceof Collection) {
                return true;
            } else if(object.getClass().isArray()) {
                 return true;
            } else if(object instanceof Enumeration) {
                 return true;
            } else if(object instanceof Iterator) {
                 return true;
            } else {
                return false;
            }
        }
}