Target.java

package com.laytonsmith.core.constructs;

import java.io.File;

/**
 * A target allows code to be exactly identified in source. It contains the line
 * number, file, and column that this target represents.
 *
 *
 */
public class Target {

    /**
     * For efficiency sake, since Targets are immutable, if you intend on using
     * a blank target, that is to say, one that has been manufactured in source,
     * you must use this target instead. If a null target is attempted to be
     * created elsewhere, an exception is thrown.
     */
    public static final Target UNKNOWN = new Target(0, null, 0, null);
    private final int line;
    private final File file;
    private final int col;

    private Target(int line, File file, int col, String Null) {
        this.line = line;
        this.file = file;
        this.col = col;
    }

    /**
     * Creates a new target that represents a location in a source file.
     *
     * @param line
     * @param file
     * @param col
     */
    public Target(int line, File file, int col) {
        if (line == 0 && col == 0 && file == null) {
            throw new RuntimeException("For efficiency sake, use Target.UNKNOWN instead of constructing"
                    + " a new Target.");
        }
        this.line = line;
        this.file = file;
        this.col = col;
    }

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

    /**
     * Returns the file. (May exist in a zip file, if the contents need to be
     * read, you should use {@link ZipReader})
     *
     * @return
     */
    public File file() {
        return file;
    }

    /**
     * Return the column.
     *
     * @return
     */
    public int col() {
        return col;
    }

	/**
	 * Returns a string in the form: <code>absolute/path:0</code>
	 * @return
	 */
    @Override
    public String toString() {
        return ( file != null ? file.getAbsolutePath() : "Unknown File" ) + ":" + line;
    }
}