com.b2international.commons.Version.java Source code

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Here is the source code for com.b2international.commons.Version.java

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/*
 * Copyright 2011-2015 B2i Healthcare Pte Ltd, http://b2i.sg
 * 
 * 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 com.b2international.commons;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;

import java.util.List;
import java.util.regex.Pattern;

import com.b2international.commons.functions.StringToIntegerParserFunction;
import com.google.common.base.Joiner;
import com.google.common.base.Splitter;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Lists;
import com.google.common.primitives.Ints;

/**
 * Represents a multi-part version string conforming to the <code>\d+(\.\d+)+</code> format.
 * 
 */
public class Version implements Comparable<Version> {

    private static final char VERSION_PART_SEPARATOR = '.';
    private static final Pattern VERSION_PATTERN = Pattern.compile("\\d+(\\.\\d+)+");

    private final List<Integer> parts;

    public Version(List<Integer> parts) {
        this.parts = ImmutableList.copyOf(parts);
    }

    @Override
    public String toString() {
        Joiner joiner = Joiner.on(VERSION_PART_SEPARATOR);
        return joiner.join(parts.iterator());
    }

    /**
     * Creates a new version by incrementing the last part of this version.
     * 
     * @return the incremented version
     */
    public Version increment() {
        List<Integer> newParts = Lists.newArrayList(parts);
        newParts.set(newParts.size() - 1, newParts.get(newParts.size() - 1) + 1);
        return new Version(newParts);
    }

    /**
     * Parses the specified {@link String} into a {@link Version} object.
     * The version string must be non-null and conform to the <code>\d+(\.\d+)+</code> format.
     * 
     * @param versionString the version string to parse
     * @return the parsed {@link Version}
     */
    public static Version parseVersion(String versionString) {
        checkNotNull(versionString, "Version string must not be null.");
        checkArgument(VERSION_PATTERN.matcher(versionString).matches(),
                "Version string format is invalid: " + versionString);
        List<Integer> versionParts = Lists.transform(
                ImmutableList.copyOf(Splitter.on(VERSION_PART_SEPARATOR).split(versionString)),
                new StringToIntegerParserFunction());
        return new Version(versionParts);
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((parts == null) ? 0 : parts.hashCode());
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Version other = (Version) obj;
        if (parts == null) {
            if (other.parts != null)
                return false;
        } else if (!parts.equals(other.parts))
            return false;
        return true;
    }

    @Override
    public int compareTo(Version other) {
        int minLength = Math.min(this.parts.size(), other.parts.size());
        int maxLength = Math.max(this.parts.size(), other.parts.size());

        int i = 0;
        for (; i < minLength; i++) {
            Integer integer1 = this.parts.get(i);
            Integer integer2 = other.parts.get(i);
            int compareResult = integer1.compareTo(integer2);
            if (compareResult != 0) {
                return compareResult;
            }
        }

        if (minLength != maxLength) {
            return Ints.compare(this.parts.size(), other.parts.size());
        } else {
            return 0;
        }
    }

}