michael@0: /*
michael@0:  * ====================================================================
michael@0:  * Licensed to the Apache Software Foundation (ASF) under one
michael@0:  * or more contributor license agreements.  See the NOTICE file
michael@0:  * distributed with this work for additional information
michael@0:  * regarding copyright ownership.  The ASF licenses this file
michael@0:  * to you under the Apache License, Version 2.0 (the
michael@0:  * "License"); you may not use this file except in compliance
michael@0:  * with the License.  You may obtain a copy of the License at
michael@0:  *
michael@0:  *   http://www.apache.org/licenses/LICENSE-2.0
michael@0:  *
michael@0:  * Unless required by applicable law or agreed to in writing,
michael@0:  * software distributed under the License is distributed on an
michael@0:  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
michael@0:  * KIND, either express or implied.  See the License for the
michael@0:  * specific language governing permissions and limitations
michael@0:  * under the License.
michael@0:  * ====================================================================
michael@0:  *
michael@0:  * This software consists of voluntary contributions made by many
michael@0:  * individuals on behalf of the Apache Software Foundation.  For more
michael@0:  * information on the Apache Software Foundation, please see
michael@0:  * <http://www.apache.org/>.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: package ch.boye.httpclientandroidlib;
michael@0: 
michael@0: import java.io.Serializable;
michael@0: import ch.boye.httpclientandroidlib.util.CharArrayBuffer;
michael@0: 
michael@0: /**
michael@0:  * Represents a protocol version. The "major.minor" numbering
michael@0:  * scheme is used to indicate versions of the protocol.
michael@0:  * <p>
michael@0:  * This class defines a protocol version as a combination of
michael@0:  * protocol name, major version number, and minor version number.
michael@0:  * Note that {@link #equals} and {@link #hashCode} are defined as
michael@0:  * final here, they cannot be overridden in derived classes.
michael@0:  * </p>
michael@0:  *
michael@0:  * @since 4.0
michael@0:  */
michael@0: public class ProtocolVersion implements Serializable, Cloneable {
michael@0: 
michael@0:     private static final long serialVersionUID = 8950662842175091068L;
michael@0: 
michael@0: 
michael@0:     /** Name of the protocol. */
michael@0:     protected final String protocol;
michael@0: 
michael@0:     /** Major version number of the protocol */
michael@0:     protected final int major;
michael@0: 
michael@0:     /** Minor version number of the protocol */
michael@0:     protected final int minor;
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Create a protocol version designator.
michael@0:      *
michael@0:      * @param protocol   the name of the protocol, for example "HTTP"
michael@0:      * @param major      the major version number of the protocol
michael@0:      * @param minor      the minor version number of the protocol
michael@0:      */
michael@0:     public ProtocolVersion(String protocol, int major, int minor) {
michael@0:         if (protocol == null) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Protocol name must not be null.");
michael@0:         }
michael@0:         if (major < 0) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Protocol major version number must not be negative.");
michael@0:         }
michael@0:         if (minor < 0) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Protocol minor version number may not be negative");
michael@0:         }
michael@0:         this.protocol = protocol;
michael@0:         this.major = major;
michael@0:         this.minor = minor;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the name of the protocol.
michael@0:      *
michael@0:      * @return the protocol name
michael@0:      */
michael@0:     public final String getProtocol() {
michael@0:         return protocol;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the major version number of the protocol.
michael@0:      *
michael@0:      * @return the major version number.
michael@0:      */
michael@0:     public final int getMajor() {
michael@0:         return major;
michael@0:     }
michael@0: 
michael@0:     /**
michael@0:      * Returns the minor version number of the HTTP protocol.
michael@0:      *
michael@0:      * @return the minor version number.
michael@0:      */
michael@0:     public final int getMinor() {
michael@0:         return minor;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Obtains a specific version of this protocol.
michael@0:      * This can be used by derived classes to instantiate themselves instead
michael@0:      * of the base class, and to define constants for commonly used versions.
michael@0:      * <br/>
michael@0:      * The default implementation in this class returns <code>this</code>
michael@0:      * if the version matches, and creates a new {@link ProtocolVersion}
michael@0:      * otherwise.
michael@0:      *
michael@0:      * @param major     the major version
michael@0:      * @param minor     the minor version
michael@0:      *
michael@0:      * @return  a protocol version with the same protocol name
michael@0:      *          and the argument version
michael@0:      */
michael@0:     public ProtocolVersion forVersion(int major, int minor) {
michael@0: 
michael@0:         if ((major == this.major) && (minor == this.minor)) {
michael@0:             return this;
michael@0:         }
michael@0: 
michael@0:         // argument checking is done in the constructor
michael@0:         return new ProtocolVersion(this.protocol, major, minor);
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Obtains a hash code consistent with {@link #equals}.
michael@0:      *
michael@0:      * @return  the hashcode of this protocol version
michael@0:      */
michael@0:     public final int hashCode() {
michael@0:         return this.protocol.hashCode() ^ (this.major * 100000) ^ this.minor;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Checks equality of this protocol version with an object.
michael@0:      * The object is equal if it is a protocl version with the same
michael@0:      * protocol name, major version number, and minor version number.
michael@0:      * The specific class of the object is <i>not</i> relevant,
michael@0:      * instances of derived classes with identical attributes are
michael@0:      * equal to instances of the base class and vice versa.
michael@0:      *
michael@0:      * @param obj       the object to compare with
michael@0:      *
michael@0:      * @return  <code>true</code> if the argument is the same protocol version,
michael@0:      *          <code>false</code> otherwise
michael@0:      */
michael@0:     public final boolean equals(Object obj) {
michael@0:         if (this == obj) {
michael@0:             return true;
michael@0:         }
michael@0:         if (!(obj instanceof ProtocolVersion)) {
michael@0:             return false;
michael@0:         }
michael@0:         ProtocolVersion that = (ProtocolVersion) obj;
michael@0: 
michael@0:         return ((this.protocol.equals(that.protocol)) &&
michael@0:                 (this.major == that.major) &&
michael@0:                 (this.minor == that.minor));
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Checks whether this protocol can be compared to another one.
michael@0:      * Only protocol versions with the same protocol name can be
michael@0:      * {@link #compareToVersion compared}.
michael@0:      *
michael@0:      * @param that      the protocol version to consider
michael@0:      *
michael@0:      * @return  <code>true</code> if {@link #compareToVersion compareToVersion}
michael@0:      *          can be called with the argument, <code>false</code> otherwise
michael@0:      */
michael@0:     public boolean isComparable(ProtocolVersion that) {
michael@0:         return (that != null) && this.protocol.equals(that.protocol);
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Compares this protocol version with another one.
michael@0:      * Only protocol versions with the same protocol name can be compared.
michael@0:      * This method does <i>not</i> define a total ordering, as it would be
michael@0:      * required for {@link java.lang.Comparable}.
michael@0:      *
michael@0:      * @param that      the protocl version to compare with
michael@0:      *
michael@0:      * @return   a negative integer, zero, or a positive integer
michael@0:      *           as this version is less than, equal to, or greater than
michael@0:      *           the argument version.
michael@0:      *
michael@0:      * @throws IllegalArgumentException
michael@0:      *         if the argument has a different protocol name than this object,
michael@0:      *         or if the argument is <code>null</code>
michael@0:      */
michael@0:     public int compareToVersion(ProtocolVersion that) {
michael@0:         if (that == null) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Protocol version must not be null.");
michael@0:         }
michael@0:         if (!this.protocol.equals(that.protocol)) {
michael@0:             throw new IllegalArgumentException
michael@0:                 ("Versions for different protocols cannot be compared. " +
michael@0:                  this + " " + that);
michael@0:         }
michael@0: 
michael@0:         int delta = getMajor() - that.getMajor();
michael@0:         if (delta == 0) {
michael@0:             delta = getMinor() - that.getMinor();
michael@0:         }
michael@0:         return delta;
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Tests if this protocol version is greater or equal to the given one.
michael@0:      *
michael@0:      * @param version   the version against which to check this version
michael@0:      *
michael@0:      * @return  <code>true</code> if this protocol version is
michael@0:      *          {@link #isComparable comparable} to the argument
michael@0:      *          and {@link #compareToVersion compares} as greater or equal,
michael@0:      *          <code>false</code> otherwise
michael@0:      */
michael@0:     public final boolean greaterEquals(ProtocolVersion version) {
michael@0:         return isComparable(version) && (compareToVersion(version) >= 0);
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Tests if this protocol version is less or equal to the given one.
michael@0:      *
michael@0:      * @param version   the version against which to check this version
michael@0:      *
michael@0:      * @return  <code>true</code> if this protocol version is
michael@0:      *          {@link #isComparable comparable} to the argument
michael@0:      *          and {@link #compareToVersion compares} as less or equal,
michael@0:      *          <code>false</code> otherwise
michael@0:      */
michael@0:     public final boolean lessEquals(ProtocolVersion version) {
michael@0:         return isComparable(version) && (compareToVersion(version) <= 0);
michael@0:     }
michael@0: 
michael@0: 
michael@0:     /**
michael@0:      * Converts this protocol version to a string.
michael@0:      *
michael@0:      * @return  a protocol version string, like "HTTP/1.1"
michael@0:      */
michael@0:     public String toString() {
michael@0:         CharArrayBuffer buffer = new CharArrayBuffer(16);
michael@0:         buffer.append(this.protocol);
michael@0:         buffer.append('/');
michael@0:         buffer.append(Integer.toString(this.major));
michael@0:         buffer.append('.');
michael@0:         buffer.append(Integer.toString(this.minor));
michael@0:         return buffer.toString();
michael@0:     }
michael@0: 
michael@0:     public Object clone() throws CloneNotSupportedException {
michael@0:         return super.clone();
michael@0:     }
michael@0: 
michael@0: }