codeelementcontainer.java

Grammatica is a C# and Java parser generator (compiler compiler). It improves upon simlar tools (lik

/*
 * CodeElementContainer.java
 *
 * This work is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2 of the License,
 * or (at your option) any later version.
 *
 * This work 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
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA
 *
 * As a special exception, the copyright holders of this library give
 * you permission to link this library with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also meet,
 * for each linked independent module, the terms and conditions of the
 * license of that module. An independent module is a module which is
 * not derived from or based on this library. If you modify this
 * library, you may extend this exception to your version of the
 * library, but you are not obligated to do so. If you do not wish to
 * do so, delete this exception statement from your version.
 *
 * Copyright (c) 2003 Per Cederberg. All rights reserved.
 */

package net.percederberg.grammatica.code;

import java.io.PrintWriter;
import java.util.Collections;
import java.util.Vector;

/**
 * The abstract base class for all code element containers. The code 
 * element containers contains other code elements.
 *
 * @author   Per Cederberg, <per at percederberg dot net>
 * @version  1.0
 */
public abstract class CodeElementContainer extends CodeElement {

    /**
     * The code element contents. This vector contains the code 
     * elements contained inside this element.
     */
    private Vector contents = new Vector();

    /**
     * Adds a code element to this container.
     * 
     * @param elem           the code element to add
     */
    protected void addElement(CodeElement elem) {
        if (!contents.contains(elem)) {
            contents.add(elem);
        }
    }
    
    /**
     * Prints all the contained code elements to the specified output 
     * stream. The code elements will be sorted by their category 
     * number before printing.
     *
     * @param out            the output stream
     * @param style          the code style to use
     * @param indent         the indentation level
     */
    protected void printContents(PrintWriter out, 
                                 CodeStyle style, 
                                 int indent) {
                                     
        CodeElement  prev = null;
        CodeElement  next;

        Collections.sort(contents);
        for (int i = 0; i < contents.size(); i++) {
            next = (CodeElement) contents.get(i);
            printSeparator(out, style, prev, next);
            next.print(out, style, indent);
            prev = next; 
        }
    }
    
    /**
     * Prints the lines separating two elements. By default this 
     * method prints a newline before the first element, and between
     * elements with different category numbers.  
     *
     * @param out            the output stream
     * @param style          the code style to use
     * @param prev           the previous element, or null if first
     * @param next           the next element, or null if last
     */
    protected void printSeparator(PrintWriter out, 
                                  CodeStyle style, 
                                  CodeElement prev, 
                                  CodeElement next) {

        if (prev == null || next == null) {
            // Do nothing
        } else if (prev.category() != next.category()) {
            out.println();
        }
    }
}