/****************************************************************
 * Licensed to the Apache Software Foundation (ASF) under one   *
 * or more contributor license agreements.  See the NOTICE file *
 * distributed with this work for additional information        *
 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
 * with the License.  You may obtain a copy of the License at   *
 *                                                              *
 *   http://www.apache.org/licenses/LICENSE-2.0                 *
 *                                                              *
 * Unless required by applicable law or agreed to in writing,   *
 * software distributed under the License is distributed on an  *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
 * KIND, either express or implied.  See the License for the    *
 * specific language governing permissions and limitations      *
 * under the License.                                           *
 ****************************************************************/

package org.apache.jsieve;

import static org.apache.jsieve.Constants.TAG_COMPARATOR;

import org.apache.jsieve.parser.generated.Token;

/**
 * <p>
 * A parsed representation of an RFC3028 TAG argument...
 * </p>
 * 
 * <code>tag = ":" identifier</code>
 */
public class TagArgument implements Argument {

    /**
     * The Tag
     */
    private String fieldTag;

    /**
     * Constructor for TagArgument.
     */
    private TagArgument() {
        super();
    }

    /**
     * Constructor for TagArgument.
     * 
     * @param token
     */
    public TagArgument(Token token) {
        this();
        setTag(token);
    }

    /**
     * Method setTag.
     * 
     * @param token
     */
    protected void setTag(Token token) {
        setTag(token.image);
    }

    /**
     * Returns the tag.
     * 
     * @return String
     */
    public String getTag() {
        return fieldTag;
    }

    /**
     * Does this argument match the given tag?
     * @param tag not null
     * @return true when the tag identifier equals that given,
     * false otherwise
     */
    public boolean is(String tag) {
       return tag.equals(fieldTag); 
    }
    
    /**
     * Is this a comparator tag?
     * @return true when identifier matches {@link Constants#TAG_COMPARATOR},
     * false otherwise
     */
    public boolean isComparator() {
        return this.is(TAG_COMPARATOR);
    }
    
    /**
     * Sets the tag.
     * 
     * @param tag
     *            The tag to set
     */
    protected void setTag(String tag) {
        fieldTag = tag;
    }

    /**
     * @see org.apache.jsieve.Argument#getValue()
     */
    public Object getValue() {
        return getTag();
    }

    /**
     * @see java.lang.Object#toString()
     */
    public String toString() {
        return (getValue() == null) ? "null" : getValue().toString();
    }

}