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Utilities for creating more complex shell commands with subcommands. It provides easy ability to parse the users command line input.

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/*
 * LICENSE
 *
 * "THE BEER-WARE LICENSE" (Revision 43):
 * "Sven Strittmatter"  wrote this file.
 * As long as you retain this notice you can do whatever you want with
 * this stuff. If we meet some day, and you think this stuff is worth it,
 * you can buy me a non alcohol-free beer in return.
 *
 * Copyright (C) 2012 "Sven Strittmatter" 
 */
package de.weltraumschaf.commons.token;

import de.weltraumschaf.commons.guava.Objects;
import de.weltraumschaf.commons.validate.Validate;

/**
 * Represents a token position in the source string.
 * 
 * The position contains the line, column and filename where the
 * token occurred. The file name is optional.
 * 
 *
 * @since 1.0.0
 * @author Sven Strittmatter <[email protected]>
 * @version $Id: $Id
 */
public final class Position {

    /**
     * A position for line 0 and column 0.
     */
    public static final Position NULL = new Position(0, 0);

    /**
     * File of the source string.
     */
    private final String file;

    /**
     * Line of occurrence.
     */
    private final int line;

    /**
     * Column of occurrence.
     */
    private final int column;

    /**
     * Initializes without file.
     *
     * @param line Line of occurrence.
     * @param column Column of occurrence.
     */
    public Position(final int line, final int column) {
        this(line, column, "");
    }

    /**
     * Dedicated constructor initializes immutable object.
     *
     * File is optional e.g. if string is parsed directly without any file.
     *
     * @param line must be greater than -1
     * @param column must be greater than -1
     * @param file must not be {@code null}, may be empty
     */
    public Position(final int line, final int column, final String file) {
        super();
        this.line   = Validate.greaterThan(line, -1, "line");
        this.column = Validate.greaterThan(column, -1, "column");
        this.file   = Validate.notNull(file, "file");
    }

    /**
     * Returns the file name of the source.
     *
     * May be null.
     *
     * @return Filename as string.
     */
    public String getFile() {
        return file;
    }

    /**
     * Returns line of occurrence in source.
     *
     * @return Line position.
     */
    public int getLine() {
        return line;
    }

    /**
     * Returns column of occurrence in source.
     *
     * @return Column position.
     */
    public int getColumn() {
        return column;
    }

    /**
     * {@inheritDoc}
     *
     * Returns human readable string representation.
     */
    @Override
    public String toString() {
        final StringBuilder str = new StringBuilder();

        if (!getFile().isEmpty()) {
            str.append(getFile()).append(' ');
        }

        str.append(String.format("(%s, %s)", getLine(), getColumn()));
        return str.toString();
    }

    /** {@inheritDoc} */
    @Override
    public int hashCode() {
        return Objects.hashCode(line, column, file);
    }

    /** {@inheritDoc} */
    @Override
    public boolean equals(final Object obj) {
        if (! (obj instanceof Position)) {
            return false;
        }

        final Position other = (Position) obj;
        return Objects.equal(line, other.line)
                && Objects.equal(column, other.column)
                && Objects.equal(file, other.file);
    }

}