ratpack.groovy.launch.GroovyVersionChecker.java Source code

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Here is the source code for ratpack.groovy.launch.GroovyVersionChecker.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * 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 ratpack.groovy.launch;

import com.google.common.base.Charsets;
import com.google.common.io.Resources;
import ratpack.api.Nullable;
import ratpack.util.ExceptionUtils;

import java.io.IOException;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class GroovyVersionChecker {

    private GroovyVersionChecker() {
    }

    public static void ensureRequiredVersionUsed(String version) throws RuntimeException {
        try {
            String minimumVersion = retrieveMinimumGroovyVersion();
            if (minimumVersion == null) {
                // Couldn't find the minimum version, we are in a strange classloader situation, continue
                return;
            }

            Pattern versionPattern = Pattern.compile("(\\d+)\\.(\\d+)\\.(\\d+).*");
            Matcher minimumVersionMatcher = versionPattern.matcher(minimumVersion);
            minimumVersionMatcher.find();
            int minimumMajor = groupAsInt(minimumVersionMatcher, 1);
            int minimumMinor = groupAsInt(minimumVersionMatcher, 2);
            int minimumPatch = groupAsInt(minimumVersionMatcher, 3);

            Matcher matcher = versionPattern.matcher(version);
            if (matcher.find()) {
                int major = groupAsInt(matcher, 1);
                int minor = groupAsInt(matcher, 2);
                int patch = groupAsInt(matcher, 3);
                if (major > minimumMajor || (major == minimumMajor && minor > minimumMinor)
                        || (major == minimumMajor && minor == minimumMinor && patch >= minimumPatch)) {
                    return;
                }
            }

            throw new RuntimeException(
                    "Ratpack requires Groovy " + minimumVersion + "+ to run but the version used is " + version);
        } catch (IOException e) {
            throw ExceptionUtils.uncheck(e);
        }
    }

    private static int groupAsInt(Matcher matcher, int group) {
        return Integer.parseInt(matcher.group(group));
    }

    @Nullable
    private static String retrieveMinimumGroovyVersion() throws IOException {
        URL resource = GroovyVersionChecker.class.getClassLoader()
                .getResource("ratpack/minimum-groovy-version.txt");
        return resource == null ? null : Resources.toString(resource, Charsets.UTF_8);
    }

}