/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2006, University of Maryland
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.filter;

import java.util.regex.Pattern;

import javax.annotation.CheckForNull;

import edu.umd.cs.findbugs.util.Util;

/**
 * Matches a String value against a predefined specification.
 *
 * Matching can be done in three modes depending on ctor matchSpec argument.
 *
 * If matchSpec is null, match will succeed for any value (including empty
 * String and null)
 *
 * If matchSpec starts with ~ character it will be treated as
 * java.util.regex.Pattern, with the ~ character omited. The pattern will be
 * matched against whole value (ie Matcher.match(), not Matcher.find())
 *
 * If matchSpec is a non-null String with any other initial charcter, exact
 * matching using String.equals(String) will be performed.
 *
 * @author rafal@caltha.pl
 */
public class NameMatch {

    private @CheckForNull
    final
    String spec;

    private @CheckForNull
    String exact;

    private @CheckForNull
    Pattern pattern;

    @Override
    public int hashCode() {
        if (spec == null) {
            return 0;
        }
        return spec.hashCode();
    }

    public boolean isUniversal() {
        if (spec == null) {
            return true;
        }
        return "~.*".equals(spec);
    }

    @Override
    public boolean equals(Object o) {
        if (!(o instanceof NameMatch)) {
            return false;
        }
        return Util.nullSafeEquals(spec, ((NameMatch) o).spec);
    }

    public String getValue() {
        if (exact != null) {
            return exact;
        }
        if (pattern != null) {
            return pattern.toString();
        }
        return "~.*";
    }

    public NameMatch(String matchSpec) {
        spec = matchSpec;
        if (matchSpec != null) {
            if (matchSpec.startsWith("~")) {
                pattern = Pattern.compile(matchSpec.substring(1));
            } else {
                exact = matchSpec;
            }
        }
    }

    public boolean match(String value) {
        if (exact != null) {
            return exact.equals(value);
        }
        if (pattern != null) {
            return pattern.matcher(value).matches();
        }
        return true;
    }

    @Override
    public String toString() {
        if (exact != null) {
            return "exact(" + exact + ")";
        }
        if (pattern != null) {
            return "regex(" + pattern.toString() + ")";
        }
        return "any()";
    }

    public String getSpec() {
        return spec;
    }
}
