can't delete conditionally from xml using Java -

i've xml file need delete elements depending on attribute value. unconditional deletion works fine won't:

nodelist nodes = doc.getelementsbytagname("host");            element d;           ( int = 0; < nodes.getlength(); i++ ) {             string state = nodes.item(i).getchildnodes().item(0).getattributes().item(0).gettextcontent();            if("down".equals(state)){               d= (element) nodes.item(0);              d.getparentnode().removechild(d);               system.out.println(state);            }             } 

there couple of problems code. first line

string state = nodes.item(i).getchildnodes().item(0).getattributes().item(0).gettextcontent(); 

which assumes 1) there no text nodes between child elements, , 2) attribute looked first attribute in list. makes code brittle , subject failure if format of input document change.

the second problem while iterating on node list, of members of list removed parent. behavior of list if detaching/removing children parent not specified in dom api, why effect vary between implementations. not sure if case here, wouldn't depend on guessing.

i suggest using xpath instead (much clearer , shorter). this:

    xpath xp = xpathfactory.newinstance().newxpath();     nodelist list = (nodelist) xp.evaluate("//node[*[@* = 'down']]", doc, xpathconstants.nodeset);     for(int i=0; < list.getlength(); ++i) {         node node = list.item(i);         node.getparentnode().removechild(node);     } 

the expression //node[*[@* = 'down']] selects <node> elements have child element has attribute value down.