javax.jmdns.impl.constants.DNSLabel Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of jmdns Show documentation

JmDNS is a Java implementation of multi-cast DNS and can be used for service registration and discovery in local area networks. JmDNS is fully compatible with Apple's Bonjour. The project was originally started in December 2002 by Arthur van Hoff at Strangeberry.

The newest version!

/*
 * Licensed 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 javax.jmdns.impl.constants;

/**
 * DNS label.
 * 
 * @author Arthur van Hoff, Jeff Sonstein, Werner Randelshofer, Pierre Frisch, Rick Blair
 */
public enum DNSLabel {
    /**
     * This is unallocated.
     */
    Unknown("", 0x80),
    /**
     * Standard label [RFC 1035]
     */
    Standard("standard label", 0x00),
    /**
     * Compressed label [RFC 1035]
     */
    Compressed("compressed label", 0xC0),
    /**
     * Extended label [RFC 2671]
     */
    Extended("extended label", 0x40);

    /**
     * DNS label types are encoded on the first 2 bits
     */
    static final int LABEL_MASK = 0xC0;
    static final int LABEL_NOT_MASK = 0x3F;
    private final String externalName;
    private final int indexValue;

    DNSLabel(String name, int index) {
        externalName = name;
        indexValue = index;
    }

    /**
     * Return the string representation of this type
     * 
     * @return String
     */
    public String externalName() {
        return externalName;
    }

    /**
     * Return the numeric value of this type
     * 
     * @return String
     */
    public int indexValue() {
        return indexValue;
    }

    /**
     * @param index index of the label
     * @return label
     */
    public static DNSLabel labelForByte(int index) {
        int maskedIndex = index & LABEL_MASK;
        for (DNSLabel label : DNSLabel.values()) {
            if (label.indexValue == maskedIndex) return label;
        }
        return Unknown;
    }

    /**
     * @param index index of the label
     * @return masked value
     */
    public static int labelValue(int index) {
        return index & LABEL_NOT_MASK;
    }

    @Override
    public String toString() {
        return this.name() + " index " + this.indexValue();
    }

}