package seedu.address.model.tag;

import java.util.Comparator;

import seedu.address.commons.exceptions.IllegalValueException;
import seedu.address.model.task.Task;

/**
 * Represents a Tag in the address book.
 * Guarantees: immutable; name is valid as declared in {@link #isValidTagName(String)}
 */
public class Tag implements Comparable<Tag>, Comparator<Tag> {

    public static final String MESSAGE_TAG_CONSTRAINTS = "Tags names should be alphanumeric";
    public static final String TAG_VALIDATION_REGEX = "\\p{Alnum}+";

    public final String tagName;

    /**
     * Validates given tag name.
     *
     * @throws IllegalValueException if the given tag name string is invalid.
     */
    public Tag(String name) throws IllegalValueException {
        assert name != null;
        String trimmedName = name.trim();
        if (!isValidTagName(trimmedName)) {
            throw new IllegalValueException(MESSAGE_TAG_CONSTRAINTS);
        }
        this.tagName = trimmedName;
    }

    /**
     * Returns true if a given string is a valid tag name.
     */
    public static boolean isValidTagName(String test) {
        return test.matches(TAG_VALIDATION_REGEX);
    }

    @Override
    public boolean equals(Object other) {
        return other == this // short circuit if same object
                || (other instanceof Tag // instanceof handles nulls
                && this.tagName.equals(((Tag) other).tagName)); // state check
    }

    @Override
    public int hashCode() {
        return tagName.hashCode();
    }

    /**
     * Format state as text for viewing.
     */
    public String toString() {
        return '[' + tagName + ']';
    }

    @Override
    public int compareTo(Tag compareTag) {
        return this.tagName.compareTo(compareTag.tagName);
    }
    
    public static Comparator<Tag> TagComparator
        = new Comparator<Tag>() {
 
        public int compare(Tag tag1, Tag tag2) {
             return tag1.compareTo(tag2);
        }
        
    };
}

@@ -123,46 +123,8 @@
 ion;
-%0Aimport seedu.address.model.task.Task;
 %0A%0A/*
@@ -304,25 +304,8 @@
 Tag%3E
-, Comparator%3CTag%3E
  %7B%0A%0A

fix compile error in Tag.java