TextPos.java

/*
 * Reference ETL Parser for Java
 * Copyright (c) 2000-2009 Constantine A Plotnikov
 *
 * Permission is hereby granted, free of charge, to any person 
 * obtaining a copy of this software and associated documentation 
 * files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, 
 * publish, distribute, sublicense, and/or sell copies of the Software, 
 * and to permit persons to whom the Software is furnished to do so, 
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be 
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 
 * SOFTWARE. 
 */
package net.sf.etl.parsers;

import java.io.Serializable;

/**
 * <p>
 * Text position. The position is represented as three numbers: line (numbered
 * from 1), column (numbered from 1), offset (numbered from 0).
 * </p>
 * 
 * <p>
 * The object is immutable.
 * </p>
 * 
 * <p>
 * Three components are used because different values are needed for different
 * consumers. Compilers and command line tools usually need line and column.
 * Editors like Eclipse TextEditor need offset.
 * </p>
 * 
 * @author const
 */
public final class TextPos implements Serializable {
	/**
	 * generated serial version id
	 */
	private static final long serialVersionUID = 7303432848120694096L;
	// NOTE consider using the type 'long' for lines and columns.
	/** line */
	private final int line;
	/** column */
	private final int column;
	/** offset */
	private final long offset;
	/** start offset */
	public static final int START_OFFSET = 0;
	/** start column */
	public static final int START_COLUMN = 1;
	/** start line */
	public static final int START_LINE = 1;
	/** Start text position of in text */
	public static final TextPos START = new TextPos(START_LINE, START_COLUMN,
			START_OFFSET);

	/**
	 * A constructor
	 * 
	 * @param line
	 *            a line
	 * @param column
	 *            a column
	 * @param offset
	 *            an offset in the file
	 */
	public TextPos(int line, int column, long offset) {
		this.column = column;
		this.line = line;
		this.offset = offset;
	}

	/**
	 * @return column
	 */
	public int column() {
		return column;
	}

	/**
	 * @return line
	 */
	public int line() {
		return line;
	}

	/**
	 * @return offset
	 */
	public long offset() {
		return offset;
	}

	/**
	 * @return string representation of position
	 */
	@Override
	public String toString() {
		return "(" + line + "," + column + "," + offset + ")";
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public boolean equals(Object arg0) {
		if (!(arg0 instanceof TextPos)) {
			return false;
		}
		final TextPos p = (TextPos) arg0;
		return line == p.line && column == p.column && offset == p.offset;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public int hashCode() {
		return line ^ column ^ (int) (offset >>> 32)
				^ (int) (offset & 0xFFFFFFFF);
	}
}