/*
 * 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.onlab.packet;

/**
 * Representation of a VLAN ID.
 */
public class VlanId {

    private final short value;

    // Based on convention used elsewhere? Check and change if needed
    public static final short UNTAGGED = (short) 0xffff;

    public static final VlanId NONE = VlanId.vlanId(UNTAGGED);

    // A VLAN ID is actually 12 bits of a VLAN tag.
    public static final short MAX_VLAN = 4095;

    protected VlanId() {
        this.value = UNTAGGED;
    }

    protected VlanId(short value) {
        this.value = value;
    }

    public static VlanId vlanId() {
        return new VlanId(UNTAGGED);
    }

    public static VlanId vlanId(short value) {
        if (value == UNTAGGED) {
            return new VlanId();
        }

        if (value > MAX_VLAN) {
            throw new IllegalArgumentException(
                    "value exceeds allowed maximum VLAN ID value (4095)");
        }
        return new VlanId(value);
    }

    public short toShort() {
        return this.value;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        if (obj instanceof VlanId) {

            VlanId other = (VlanId) obj;

             if (this.value == other.value) {
                return true;
            }
        }

        return false;
    }

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

    @Override
    public String toString() {
        return String.valueOf(this.value);
    }
}