How to skip the parent tag, based on the value of a child tag in XML Parsing using SAX Parser

Vipul Reddy Published at Dev

Vipul Reddy

<root>
<parent>
    <child1> 30</child1>
    <child2> 30</child2>
    <child3> 30</child3>
</parent>
 <parent>
    <child1> 20</child1>
    <child2> 30</child2>
    <child3> 30</child3>
</parent>
 <parent>
    <child1> 30</child1>
    <child2> 30</child2>
    <child3> 30</child3>
</parent>
</root>

I am really new to the world of coding and to sax parsing.. Consider the above XML, what I need is. .. based on the value of the tag child1, if it is greater than 20, only then I would want to parse the remaining child tags(child2 and child3), otherwise I would want to move on to the next parent tag.

Could anyone pls suggest what would be the ideal way to do it?

Maurice Perry

Something like that:

...
private boolean skipChildren;
private StringBuilder buf = new StringBuilder();
...

@Override
public void startElement(String uri, String localName, String qName,
        Attributes attributes) throws SAXException {
    if (qName.equals("parent")) {
        skipChildren = false;
        ...
    } else if (qName.equals("child1")) {
        buf.setLength(0);
        ...
    } else if (qName.startsWith("child")) {
        if (!skipChildren) {
            buf.setLength(0);
            ...
        }
    }
}

@Override
public void endElement(String uri, String localName, String qName)
        throws SAXException {
    if (qName.equals("parent")) {
        ...
    } else if (qName.equals("child1")) {
        int value = Integer.parseInt(buf.toString().trim());
        if (value <= 20) {
            skipChildren = true;
        }
        ...
    } else if (qName.startsWith("child")) {
        if (!skipChildren) {
            int value = Integer.parseInt(buf.toString().trim());
            doSomethingWith(value);
        }
    }
}

@Override
public void characters(char[] ch, int start, int length) {
    if (!skipChildren) {
        buf.append(ch, start, length);
    }
}

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