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/*
* ====================================================================
* 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.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
*
* This class defines a protocol version as a combination of
* protocol name, major version number, and minor version number.
* Note that {@link #equals} and {@link #hashCode} are defined as
* final here, they cannot be overridden in derived classes.
*
*
* @since 4.0
*/
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class ProtocolVersion implements Serializable, Cloneable {
private static final long serialVersionUID = 8950662842175091068L;
/** Name of the protocol. */
protected final String protocol;
/** Major version number of the protocol */
protected final int major;
/** Minor version number of the protocol */
protected final int minor;
/**
* Create a protocol version designator.
*
* @param protocol the name of the protocol, for example "HTTP"
* @param major the major version number of the protocol
* @param minor the minor version number of the protocol
*/
public ProtocolVersion(final String protocol, final int major, final int minor) {
this.protocol = Args.notNull(protocol, "Protocol name");
this.major = Args.notNegative(major, "Protocol minor version");
this.minor = Args.notNegative(minor, "Protocol minor version");
}
/**
* Returns the name of the protocol.
*
* @return the protocol name
*/
public final String getProtocol() {
return protocol;
}
/**
* Returns the major version number of the protocol.
*
* @return the major version number.
*/
public final int getMajor() {
return major;
}
/**
* Returns the minor version number of the HTTP protocol.
*
* @return the minor version number.
*/
public final int getMinor() {
return minor;
}
/**
* Obtains a specific version of this protocol.
* This can be used by derived classes to instantiate themselves instead
* of the base class, and to define constants for commonly used versions.
*
* The default implementation in this class returns {@code this}
* if the version matches, and creates a new {@link ProtocolVersion}
* otherwise.
*
*
* @param major the major version
* @param minor the minor version
*
* @return a protocol version with the same protocol name
* and the argument version
*/
public ProtocolVersion forVersion(final int major, final int minor) {
if ((major == this.major) && (minor == this.minor)) {
return this;
}
// argument checking is done in the constructor
return new ProtocolVersion(this.protocol, major, minor);
}
/**
* Obtains a hash code consistent with {@link #equals}.
*
* @return the hashcode of this protocol version
*/
@Override
public final int hashCode() {
return this.protocol.hashCode() ^ (this.major * 100000) ^ this.minor;
}
/**
* Checks equality of this protocol version with an object.
* The object is equal if it is a protocl version with the same
* protocol name, major version number, and minor version number.
* The specific class of the object is not relevant,
* instances of derived classes with identical attributes are
* equal to instances of the base class and vice versa.
*
* @param obj the object to compare with
*
* @return {@code true} if the argument is the same protocol version,
* {@code false} otherwise
*/
@Override
public final boolean equals(final Object obj) {
if (this == obj) {
return true;
}
if (!(obj instanceof ProtocolVersion)) {
return false;
}
final ProtocolVersion that = (ProtocolVersion) obj;
return ((this.protocol.equals(that.protocol)) &&
(this.major == that.major) &&
(this.minor == that.minor));
}
/**
* Checks whether this protocol can be compared to another one.
* Only protocol versions with the same protocol name can be
* {@link #compareToVersion compared}.
*
* @param that the protocol version to consider
*
* @return {@code true} if {@link #compareToVersion compareToVersion}
* can be called with the argument, {@code false} otherwise
*/
public boolean isComparable(final ProtocolVersion that) {
return (that != null) && this.protocol.equals(that.protocol);
}
/**
* Compares this protocol version with another one.
* Only protocol versions with the same protocol name can be compared.
* This method does not define a total ordering, as it would be
* required for {@link java.lang.Comparable}.
*
* @param that the protocol version to compare with
*
* @return a negative integer, zero, or a positive integer
* as this version is less than, equal to, or greater than
* the argument version.
*
* @throws IllegalArgumentException
* if the argument has a different protocol name than this object,
* or if the argument is {@code null}
*/
public int compareToVersion(final ProtocolVersion that) {
Args.notNull(that, "Protocol version");
Args.check(this.protocol.equals(that.protocol),
"Versions for different protocols cannot be compared: %s %s", this, that);
int delta = getMajor() - that.getMajor();
if (delta == 0) {
delta = getMinor() - that.getMinor();
}
return delta;
}
/**
* Tests if this protocol version is greater or equal to the given one.
*
* @param version the version against which to check this version
*
* @return {@code true} if this protocol version is
* {@link #isComparable comparable} to the argument
* and {@link #compareToVersion compares} as greater or equal,
* {@code false} otherwise
*/
public final boolean greaterEquals(final ProtocolVersion version) {
return isComparable(version) && (compareToVersion(version) >= 0);
}
/**
* Tests if this protocol version is less or equal to the given one.
*
* @param version the version against which to check this version
*
* @return {@code true} if this protocol version is
* {@link #isComparable comparable} to the argument
* and {@link #compareToVersion compares} as less or equal,
* {@code false} otherwise
*/
public final boolean lessEquals(final ProtocolVersion version) {
return isComparable(version) && (compareToVersion(version) <= 0);
}
/**
* Converts this protocol version to a string.
*
* @return a protocol version string, like "HTTP/1.1"
*/
@Override
public String toString() {
final StringBuilder buffer = new StringBuilder();
buffer.append(this.protocol);
buffer.append('/');
buffer.append(Integer.toString(this.major));
buffer.append('.');
buffer.append(Integer.toString(this.minor));
return buffer.toString();
}
@Override
public Object clone() throws CloneNotSupportedException {
return super.clone();
}
}