source: trunk/quest-core-events/src/main/java/de/ugoe/cs/quest/SequenceInstanceOf.java @ 541

package de.ugoe.cs.quest;

import java.util.Collection;
import java.util.List;
import java.util.NoSuchElementException;

import de.ugoe.cs.quest.eventcore.Event;

/**
 * <p>
 * Helper class that can be used to determine if an object is a sequence or a
 * collection of sequences. {@code instanceof} does not work, because of
 * the type erasure of generics.
 * </p>
 * 
 * @author Steffen Herbold
 * @version 1.0
 */
public class SequenceInstanceOf {
        
        /**
         * <p>
         * Private constructor to prevent initializing of the class.
         * </p>
         */
        private SequenceInstanceOf() {
                
        }

        /**
         * <p>
         * Checks if an object is of type {@link Collection}&lt;{@link List}&lt;
         * {@link Event}&lt;?&gt;&gt;&gt;.
         * </p>
         * 
         * @param obj
         *            object that is checked
         * @return true, if the obj is of type {@link Collection}&lt;{@link List}
         *         &lt; {@link Event}&lt;?&gt;&gt;&gt;; false otherwise
         */
        public static boolean isCollectionOfSequences(Object obj) {
                try {
                        if (obj instanceof Collection<?>) {
                                Object listObj = ((Collection<?>) obj).iterator().next();
                                if (listObj instanceof List<?>) {
                                        if (((List<?>) listObj).iterator().next() instanceof Event) {
                                                return true;
                                        }
                                }
                        }
                } catch (NoSuchElementException e) {
                }
                return false;
        }

        /**
         * <p>
         * Checks if an object is of type {@link List}&lt;{@link Event}
         * &lt;?&gt;&gt;.
         * </p>
         * 
         * @param obj
         *            object that is checked
         * @return true, if obj is of type {@link List}&lt;{@link Event}
         *         &lt;?&gt;&gt;; false otherwise
         */
        public static boolean isEventSequence(Object obj) {
                try {
                        if (obj instanceof List<?>) {
                                if (((List<?>) obj).iterator().next() instanceof Event) {
                                        return true;
                                }
                        }
                } catch (NoSuchElementException e) {
                }
                return false;
        }

}