Quantifier.java

/*
 * Copyright (C) 2010 eXo Platform SAS.
 *
 * This 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 software 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 software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */

package org.exoplatform.web.controller.regexp;

import java.io.IOException;


/**
 * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
 * @version $Revision$
 */
public class Quantifier {

    public enum Mode {

        GREEDY(""), RELUCTANT("?"), POSSESSIVE("+");

        /** . */
        private final String value;

        Mode(String value) {
            this.value = value;
        }
    }

    public static class Range {

        /** . */
        private final int min;

        /** . */
        private final Integer max;

        public Range(int min, Integer max) {
            this.min = min;
            this.max = max;
        }

        @Override
        public boolean equals(Object o) {
            if (o == this) {
                return true;
            } else if (o instanceof Range) {
                Range that = (Range) o;
                return min == that.min && (max == null ? that.max == null : max.equals(that.max));
            }
            return false;
        }

        public static Range onceOrNotAtAll() {
            return new Range(0, 1);
        }

        public static Range zeroOrMore() {
            return new Range(0, null);
        }

        public static Range oneOrMore() {
            return new Range(1, null);
        }

        public static Range exactly(int value) {
            return new Range(value, value);
        }

        public static Range atLeast(int value) {
            return new Range(value, null);
        }

        public static Range between(int min, int max) {
            return new Range(min, max);
        }
    }

    /** . */
    private final Mode mode;

    /** . */
    private final Range range;

    public Quantifier(Mode mode, int min, Integer max) {
        if (mode == null) {
            throw new NullPointerException("No null mode accepted");
        }

        //
        this.mode = mode;
        this.range = new Range(min, max);
    }

    public Quantifier(Mode mode, Range range) {
        if (mode == null) {
            throw new NullPointerException("No null mode accepted");
        }
        if (range == null) {
            throw new NullPointerException("No null range accepted");
        }

        //
        this.mode = mode;
        this.range = range;
    }

    public int getMin() {
        return range.min;
    }

    public static Quantifier onceOrNotAtAll(Mode mode) {
        return new Quantifier(mode, 0, 1);
    }

    public static Quantifier zeroOrMore(Mode mode) {
        return new Quantifier(mode, 0, null);
    }

    public static Quantifier oneOrMore(Mode mode) {
        return new Quantifier(mode, 1, null);
    }

    public static Quantifier exactly(Mode mode, int value) {
        return new Quantifier(mode, value, value);
    }

    public static Quantifier atLeast(Mode mode, int value) {
        return new Quantifier(mode, value, null);
    }

    public static Quantifier between(Mode mode, int min, int max) {
        return new Quantifier(mode, min, max);
    }

    @Override
    public boolean equals(Object o) {
        if (o == this) {
            return true;
        } else if (o instanceof Quantifier) {
            Quantifier that = (Quantifier) o;
            return mode == that.mode && range.equals(that.range);
        }
        return false;
    }

    @Override
    public String toString() {
        try {
            StringBuilder sb = new StringBuilder();
            toString(sb);
            return sb.toString();
        } catch (IOException e) {
            throw new AssertionError(e);
        }
    }

    public void toString(Appendable appendable) throws IOException {
        if (range.min == 0) {
            if (range.max == null) {
                appendable.append('*').append(mode.value);
            } else if (range.max == 1) {
                appendable.append('?').append(mode.value);
            }
        } else if (range.min == 1 && range.max == null) {
            appendable.append('+').append(mode.value);
        } else if (range.max == null) {
            appendable.append('{').append(Integer.toString(range.min)).append(",").append('}').append(mode.value);
        } else if (range.min == range.max) {
            appendable.append('{').append(Integer.toString(range.min)).append('}').append(mode.value);
        } else {
            appendable.append('{').append(Integer.toString(range.min)).append(",").append(range.max.toString()).append('}')
                    .append(mode.value);
        }
    }
}