001///////////////////////////////////////////////////////////////////////////////////////////////
002// checkstyle: Checks Java source code and other text files for adherence to a set of rules.
003// Copyright (C) 2001-2026 the original author or authors.
004//
005// This library is free software; you can redistribute it and/or
006// modify it under the terms of the GNU Lesser General Public
007// License as published by the Free Software Foundation; either
008// version 2.1 of the License, or (at your option) any later version.
009//
010// This library is distributed in the hope that it will be useful,
011// but WITHOUT ANY WARRANTY; without even the implied warranty of
012// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
013// Lesser General Public License for more details.
014//
015// You should have received a copy of the GNU Lesser General Public
016// License along with this library; if not, write to the Free Software
017// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
018///////////////////////////////////////////////////////////////////////////////////////////////
019
020package com.puppycrawl.tools.checkstyle.checks.imports;
021
022/**
023 * Base class for import rules.
024 */
025public abstract class AbstractImportRule {
026
027    /** Indicates whether to allow access or not. */
028    private final boolean allowed;
029
030    /** Indicates if the rule only applies to this package. */
031    private final boolean localOnly;
032
033    /**
034     * Indicates if the name is to be interpreted as a regular expression.
035     */
036    private final boolean regExp;
037
038    /**
039     * Constructs an instance.
040     *
041     * @param allow whether to allow access.
042     * @param localOnly whether the rule is to be applied locally only.
043     * @param regExp whether the name is to be interpreted as a regular expression.
044     */
045    protected AbstractImportRule(final boolean allow, final boolean localOnly,
046        final boolean regExp) {
047        allowed = allow;
048        this.localOnly = localOnly;
049        this.regExp = regExp;
050    }
051
052    /**
053     * Verifies whether a package name is used.
054     *
055     * @param forImport the import to check.
056     * @return a result {@link AccessResult} indicating whether it can be used.
057     */
058    public abstract AccessResult verifyImport(String forImport);
059
060    /**
061     * Return true if the guard is to only be applied locally or false.
062     *
063     * @return whether the guard is to only be applied locally.
064     */
065    public boolean isLocalOnly() {
066        return localOnly;
067    }
068
069    /**
070     * Return true if the name is to be interpreted as a regular expression or false.
071     *
072     * @return whether the name is to be interpreted as a regular expression.
073     */
074    protected boolean isRegExp() {
075        return regExp;
076    }
077
078    /**
079     * Returns the appropriate {@link AccessResult} based on whether there
080     * was a match and if the rule is to allow access.
081     *
082     * @param matched indicates whether there was a match.
083     * @return An appropriate {@code AccessResult}.
084     */
085    protected AccessResult calculateResult(final boolean matched) {
086        AccessResult result = AccessResult.UNKNOWN;
087
088        if (matched) {
089            if (allowed) {
090                result = AccessResult.ALLOWED;
091            }
092            else {
093                result = AccessResult.DISALLOWED;
094            }
095        }
096
097        return result;
098    }
099
100}