ratpack.groovy.internal.GroovyVersionCheck.java Source code

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Here is the source code for ratpack.groovy.internal.GroovyVersionCheck.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.internal;

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

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

public class GroovyVersionCheck {

    private GroovyVersionCheck() {
    }

    public static void ensureRequiredVersionUsed(String groovyVersion) throws RuntimeException {
        String minimumVersion = maybeLoadMinimumGroovyVersion();
        if (minimumVersion != null) {
            ensureRequiredVersionUsed(groovyVersion, minimumVersion);
        }
    }

    static void ensureRequiredVersionUsed(String groovyVersion, String minimumVersion) {
        Pattern versionPattern = Pattern.compile("(\\d+)\\.(\\d+)\\.(\\d+).*");
        Matcher minimumVersionMatcher = versionPattern.matcher(minimumVersion);
        if (!minimumVersionMatcher.find()) {
            throw new IllegalStateException("Minimum groovy isn't in expected format");
        }
        int minimumMajor = groupAsInt(minimumVersionMatcher, 1);
        int minimumMinor = groupAsInt(minimumVersionMatcher, 2);
        int minimumPatch = groupAsInt(minimumVersionMatcher, 3);

        Matcher matcher = versionPattern.matcher(groovyVersion);
        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 " + groovyVersion);
    }

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

    @Nullable
    public static String maybeLoadMinimumGroovyVersion() {
        URL resource = GroovyVersionCheck.class.getClassLoader().getResource("ratpack/minimum-groovy-version.txt");
        try {
            return resource == null ? null : Resources.toString(resource, Charsets.UTF_8);
        } catch (IOException e) {
            return null;
        }
    }

}