net.grinder.util.VersionNumber.java Source code

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Here is the source code for net.grinder.util.VersionNumber.java

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/* 
 * 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 net.grinder.util;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.math.NumberUtils;

import java.util.StringTokenizer;

/**
 * Comparable Version number.
 *
 * @author JunHo Yoon
 * @since 3.1.1
 */
public class VersionNumber implements Comparable<VersionNumber> {
    private final int[] digits;

    /**
     * Parses a string like "1.0.2" into the version number.
     *
     * @param num parameter string
     */
    public VersionNumber(String num) {
        StringTokenizer tokens = new StringTokenizer(num, ".-_");
        this.digits = new int[tokens.countTokens()];
        if (this.digits.length < 2) {
            throw new IllegalArgumentException("Failed to parse " + num + " as version number");
        }

        int i = 0;
        while (tokens.hasMoreTokens()) {
            String token = tokens.nextToken().toLowerCase();
            if (token.equals("*")) {
                this.digits[i++] = 1000;
            } else if (StringUtils.startsWithIgnoreCase(token, "snapshot")) {
                this.digits[i - 1]--;
                //noinspection UnusedAssignment
                this.digits[i++] = 1000;
                break;
            } else {
                if (NumberUtils.isNumber(token)) {
                    this.digits[i++] = Integer.parseInt(token);
                }
            }
        }
    }

    @Override
    public String toString() {
        StringBuilder buf = new StringBuilder();
        for (int i = 0; i < this.digits.length; i++) {
            if (i != 0) {
                buf.append('.');
            }
            buf.append(Integer.toString(this.digits[i]));
        }
        return buf.toString();
    }

    @Override
    public boolean equals(Object o) {
        return o instanceof VersionNumber && compareTo((VersionNumber) o) == 0;
    }

    @Override
    public int hashCode() {
        int x = 0;
        for (int i : this.digits) {
            x = x << 1 | i;
        }
        return x;
    }

    /*
     * (non-Javadoc)
     * 
     * @see java.lang.Comparable#compareTo(java.lang.Object)
     */
    @Override
    public int compareTo(VersionNumber rhs) {
        for (int i = 0;; i++) {
            if (i == this.digits.length && i == rhs.digits.length) {
                return 0; // equals
            }
            if (i == this.digits.length) {
                return -1; // rhs is larger
            }
            if (i == rhs.digits.length) {
                return 1;
            }

            int r = this.digits[i] - rhs.digits[i];
            if (r != 0) {
                return r;
            }
        }
    }
}