Reference to labels -- occurs='?'

• RELAX: zero or one times
• Java: "Integer" (which can be null) rather than "int"

<?xml version="1.0"?>
<!DOCTYPE module SYSTEM "relaxCore.dtd">
<module>

  <interface>
    <export label="RefZeroOne"/>
  </interface>

  <elementRule role="RefZeroOne">
    <ref label="Target" occurs="?"/>
  </elementRule>

  <tag name="ref" role="RefZeroOne">
  </tag>

  <elementRule role="Target" type="int">
  </elementRule>

  <tag name="target" role="Target">
  </tag>

</module>

import org.w3c.dom.*;

/**
 * <b>RefZeroOne</b> is generated by Relaxer based on RefZeroOne.rlx.
 * This class is derived from:
 * 
 * <!-- for programmer
 * <elementRule role="RefZeroOne">
 *   <ref label="Target" occurs="?"/>
 * </elementRule>
 * 
 * <tag name="ref" role="RefZeroOne"/>
 * -->
 * <!-- for javadoc -->
 * <pre> &lt;elementRule role="RefZeroOne"&gt;
 *   &lt;ref label="Target" occurs="?"/&gt;
 * &lt;/elementRule&gt;
 * &lt;tag name="ref" role="RefZeroOne"/&gt;
 * </pre>
 *
 * @version RefZeroOne.rlx (Mon Jul 31 06:00:10 JST 2000)
 * @author  Relaxer 0.10 (by ASAMI@Yokohama)
 */
public class RefZeroOne implements java.io.Serializable {
    private Integer target;

    /**
     * Creates a <code>RefZeroOne</code>.
     *
     */
    public RefZeroOne() {
    }

    /**
     * Creates a <code>RefZeroOne</code> by the Stack <code>stack</code>
     * that contains Elements.
     * This constructor is supposed to be used internally
     * by the Relaxer system.
     *
     * @param stack
     */
    public RefZeroOne(RStack stack) {
        setup(stack);
    }

    /**
     * Creates a <code>RefZeroOne</code> by the Document <code>doc</code>.
     *
     * @param doc
     */
    public RefZeroOne(Document doc) {
        setup(doc.getDocumentElement());
    }

    /**
     * Creates a <code>RefZeroOne</code> by the Element <code>element</code>.
     *
     * @param element
     */
    public RefZeroOne(Element element) {
        setup(element);
    }

    /**
     * Initializes the <code>RefZeroOne</code> by the Document <code>doc</code>.
     *
     * @param doc
     */
    public void setup(Document doc) {
        setup(doc.getDocumentElement());
    }

    /**
     * Initializes the <code>RefZeroOne</code> by the Element <code>element</code>.
     *
     * @param element
     */
    public void setup(Element element) {
        init(element);
    }

    /**
     * Initializes the <code>RefZeroOne</code> by the Stack <code>stack</code>
     * that contains Elements.
     * This constructor is supposed to be used internally
     * by the Relaxer system.
     *
     * @param stack
     */
    public void setup(RStack stack) {
        setup(stack.popElement());
    }

    /**
     * @param element
     */
    private void init(Element element) {
        RStack stack = new RStack(element);
        target = URelaxer.getElementPropertyAsIntByStack(stack, "target");
    }

    /**
     * Creates a DOM representation of the object.
     * Result is appended to the Node <code>parent</code>.
     *
     * @param parent
     */
    public void makeElement(Node parent) {
        Document doc;
        if (parent instanceof Document) {
            doc = (Document)parent;
        } else {
            doc = parent.getOwnerDocument();
        }
        Element element = doc.createElement("ref");
        int size;
        if (target != null) {
            URelaxer.setElementPropertyByInt(element, "target", target);
        }
        parent.appendChild(element);
    }

    /**
     * Gets the Integer property <b>target</b>.
     *
     * @return Integer
     */
    public final Integer getTarget() {
        return (target);
    }

    /**
     * Sets the Integer property <b>target</b>.
     *
     * @param target
     */
    public final void setTarget(Integer target) {
        this.target = target;
    }

    /**
     * Tests if a Element <code>element</code> is valid
     * for the <code>RefZeroOne</code>.
     *
     * @param element
     * @return boolean
     */
    public static boolean isMatch(Element element) {
        String tagName = element.getTagName();
        if (!"ref".equals(tagName)) {
            return (false);
        }
        RStack target = new RStack(element);
        Element child;
        child = target.peekElement();
        if (child != null) {
            if ("target".equals(child.getTagName())) {
                target.popElement();
            }
        }
        if (!target.isEmptyElement()) {
            return (false);
        }
        return (true);
    }

    /**
     * Tests if elements contained in a Stack <code>stack</code>
     * is valid for the <code>RefZeroOne</code>.
     * This mehtod is supposed to be used internally
     * by the Relaxer system.
     *
     * @param stack
     * @return boolean
     */
    public static boolean isMatch(RStack stack) {
        Element element = stack.peekElement();
        if (element == null) {
            return (false);
        }
        return (isMatch(element));
    }

    /**
     * Tests if elements contained in a Stack <code>stack</code>
     * is valid for the <code>RefZeroOne</code>.
     * This method consumes the stack contents during matching operation.
     * This mehtod is supposed to be used internally
     * by the Relaxer system.
     *
     * @param stack
     * @return boolean
     */
    public static boolean isMatchHungry(RStack stack) {
        Element element = stack.peekElement();
        if (element == null) {
            return (false);
        }
        if (isMatch(element)) {
            stack.popElement();
            return (true);
        } else {
            return (false);
        }
    }
}