org.apache.maven.plugins.checkstyle.RuleUtil Maven / Gradle / Ivy

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Generates a report on violations of code style and optionally fails the build if violations are detected.
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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.
 */
package org.apache.maven.plugins.checkstyle;

import java.util.ArrayList;
import java.util.List;

import com.puppycrawl.tools.checkstyle.api.AuditEvent;
import org.apache.commons.lang3.StringUtils;

/**
 * Tooling for Checkstyle rules conventions: names, categories.
 *
 * @author Hervé Boutemy
 * @since 2.13
 */
public final class RuleUtil {
    private RuleUtil() {
        // hide utility class constructor
    }

    private static final String CHECKSTYLE_PACKAGE = "com.puppycrawl.tools.checkstyle.checks";

    /**
     * Get the rule name from an audit event.
     *
     * @param event the audit event
     * @return the rule name, which is the class name without package and removed eventual "Check" suffix
     */
    public static String getName(AuditEvent event) {
        return getName(event.getSourceName());
    }
    /**
     * Get the rule name from an audit event source name.
     *
     * @param eventSrcName the audit event source name
     * @return the rule name, which is the class name without package and removed eventual "Check" suffix
     */
    public static String getName(String eventSrcName) {
        if (eventSrcName == null) {
            return null;
        }

        if (eventSrcName.endsWith("Check")) {
            eventSrcName = eventSrcName.substring(0, eventSrcName.length() - 5);
        }

        return eventSrcName.substring(eventSrcName.lastIndexOf('.') + 1);
    }

    /**
     * Get the rule category from an audit event.
     *
     * @param event the audit event
     * @return the rule category, which is the last package name or "misc" or "extension"
     */
    public static String getCategory(AuditEvent event) {
        return getCategory(event.getSourceName());
    }

    /**
     * Get the rule category from an audit event source name.
     *
     * @param eventSrcName the audit event source name
     * @return the rule category, which is the last package name or "misc" or "extension"
     */
    public static String getCategory(String eventSrcName) {
        if (eventSrcName == null) {
            return null;
        }

        int end = eventSrcName.lastIndexOf('.');
        eventSrcName = end == -1 ? eventSrcName : eventSrcName.substring(0, end);

        if (CHECKSTYLE_PACKAGE.equals(eventSrcName)) {
            return "misc";
        } else if (!eventSrcName.startsWith(CHECKSTYLE_PACKAGE)) {
            return "extension";
        }

        return eventSrcName.substring(eventSrcName.lastIndexOf('.') + 1);
    }

    public static List parseMatchers(String[] specs) {
        List matchers = new ArrayList<>();
        for (String spec : specs) {
            if (StringUtils.isBlank(spec)) {
                continue;
            }
            spec = spec.trim();
            Matcher matcher;
            if (Character.isUpperCase(spec.charAt(0))) {
                // spec starting with uppercase is a rule name
                matcher = new RuleMatcher(spec);
            } else if ("misc".equals(spec)) {
                // "misc" is a special case
                matcher = new PackageMatcher(CHECKSTYLE_PACKAGE);
            } else if ("extension".equals(spec)) {
                // "extension" is a special case
                matcher = new ExtensionMatcher();
            } else if (!spec.contains(".")) {
                matcher = new PackageMatcher(CHECKSTYLE_PACKAGE + '.' + spec);
            } else {
                // by default, spec is a package name
                matcher = new PackageMatcher(spec);
            }
            matchers.add(matcher);
        }
        return matchers;
    }

    /**
     * Audit event source name matcher.
     */
    public interface Matcher {
        /**
         * Does the event source name match?
         * @param eventSrcName the event source name
         * @return boolean
         */
        boolean match(String eventSrcName);
    }

    private static class RuleMatcher implements Matcher {
        private final String rule;

        RuleMatcher(String rule) {
            this.rule = rule;
        }

        public boolean match(String eventSrcName) {
            return rule.equals(getName(eventSrcName));
        }
    }

    private static class PackageMatcher implements Matcher {
        private final String packageName;

        PackageMatcher(String packageName) {
            this.packageName = packageName;
        }

        public boolean match(String eventSrcName) {
            return eventSrcName.startsWith(packageName)
                    && !eventSrcName.substring(packageName.length() + 1).contains(".");
        }
    }

    /**
     * An extension does not start with Checkstyle package.
     */
    private static class ExtensionMatcher implements Matcher {
        public boolean match(String eventSrcName) {
            return !eventSrcName.startsWith(CHECKSTYLE_PACKAGE);
        }
    }
}