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
022import java.util.regex.Pattern;
023
024/**
025 * Represents an import rules for a specific file. Only the file name is
026 * considered and only files processed by TreeWalker. The file's
027 * extension is ignored.
028 */
029class FileImportControl extends AbstractImportControl {
030
031    /** The name for the file. */
032    private final String name;
033    /** The regex pattern for exact matches - only not null if regex is true. */
034    private final Pattern patternForExactMatch;
035    /** If this file name represents a regular expression. */
036    private final boolean regex;
037
038    /**
039     * Construct a file node.
040     *
041     * @param parent the parent node.
042     * @param name the name of the file.
043     * @param regex flags interpretation of name as regex pattern.
044     */
045    /* package */ FileImportControl(PkgImportControl parent, String name, boolean regex) {
046        super(parent, MismatchStrategy.DELEGATE_TO_PARENT);
047        this.regex = regex;
048        this.name = name;
049        patternForExactMatch = createPatternForExactMatch(name);
050    }
051
052    /**
053     * Creates a Pattern from {@code expression}.
054     *
055     * @param expression a self-contained regular expression matching the full
056     *     file name exactly.
057     * @return a Pattern.
058     */
059    private static Pattern createPatternForExactMatch(String expression) {
060        return Pattern.compile(expression);
061    }
062
063    @Override
064    public AbstractImportControl locateFinest(String forPkg, String forFileName) {
065        AbstractImportControl finestMatch = null;
066        // Check if we are a match.
067        if (matchesExactly(forPkg, forFileName)) {
068            finestMatch = this;
069        }
070        return finestMatch;
071    }
072
073    @Override
074    protected boolean matchesExactly(String pkg, String fileName) {
075        final boolean result;
076        if (fileName == null) {
077            result = false;
078        }
079        else if (regex) {
080            result = patternForExactMatch.matcher(fileName).matches();
081        }
082        else {
083            result = name.equals(fileName);
084        }
085        return result;
086    }
087
088}