[jdom-interest] bug in PartialList addAll method?

Mika Haapakorpi mika.haapakorpi at sensor-sc.fi
Mon Jun 18 10:05:21 PDT 2001


The following piece of code throws a java.util.NoSuchElementException
        Element e = new Element("koe");
        List v = new Vector();
        v.add(new Element("koe1"));
        v.add(new Element("koe2"));
        List v2 = new Vector();
        v2.add(new Element("koe1"));
        v2.add(new Element("koe2"));
        e.getChildren("koe").addAll(v2); <- exception thrown from this line:


Exception in thread "main" java.util.NoSuchElementException
        at java.util.LinkedList.getLast(LinkedList.java:109)
        at org.jdom.PartialList.addAll(PartialList.java:248)
        at SAXBuilderDemo.main(SAXBuilderDemo.java:215)

I'm using todays' snapshot of jdom; 18.6.2001


The reason for this seems quite obvious as we can see from the source of PartialList:

public boolean addAll(Collection c) {
        if (backingList.isEmpty()) {
            return addAll(0, c);
        } else {
            return addAll(backingList.indexOf(getLast()) + 1, c);

if this PartialList is empty and backing list is not the getLast method will throw it.

I tried this simple fix which seem to be obvious solution also solving some other problems of addAll:

public boolean addAll(Collection c) {

        // XXX What if the element already has a parent?
        for (Iterator i = c.iterator(); i.hasNext(); ) {
            Object o = i.next();
            if (o instanceof Element) {
                ((Element)o).setParent(parent);  // null is OK

        if (backingList.isEmpty() || this.isEmpty()) {
            return (backingList.addAll(c) && super.addAll(c));        
        } else {
            return ( backingList.addAll(backingList.indexOf(this.getLast()) + 1, c) &&
                     super.addAll(c) );

but the result was unexpected: it did not throw any exception but the element e looked like this:

<koe><koe1 /><koe2 /><koe1 /><koe2 /><koe1 /><koe2 /><koe1 /><koe2 /><koe1 /><koe2 /></koe>

instead of 4 subelements there was 10 of them ???????

Now i'm using this:

public boolean addAll(Collection c) {
        Iterator i = c.iterator();
        boolean value = true;
        while(i.hasNext() && value ) value = this.add(i.next());
        return value;

This fix seems to work but of course all the elements are always added to the end of the entire content of e not after the last element in PartialList (like it should be ... ?)

Mika Haapakorpi
Sensor Software Consulting
mika.haapakorpi at sensor-sc.fi

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