Question

I have something like this:

    import java.io.FileInputStream;
    import java.io.FileOutputStream;
    import java.io.OutputStream;
    import java.util.HashMap;
    import java.util.Map;
    import javax.xml.stream.*;
    import javax.xml.stream.events.*;

    public class MyClass implements javax.xml.stream.StreamFilter
    {
        private Map myMap= new HashMap();

        public Map getMap()
        {
            return this.myMap;
        }

        public void addElement(String text)
        {
            this.myMap.put(text, "value");
        }

        public void doSomething(String strValue)
        {

            try
            {
                XMLInputFactory xmlif = null;
                xmlif = XMLInputFactory.newInstance();          
                FileInputStream fis = new FileInputStream("myFile.xml");
                XMLStreamReader xmlr = xmlif.createFilteredReader(xmlif.createXMLStreamReader(fis),new MyClass());

                XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
                OutputStream fileStream = new FileOutputStream("myFileOutput");
                XMLStreamWriter xmlWriter = outputFactory.createXMLStreamWriter(fileStream);

                addElement(strValue);
                System.out.println(getMap().size()+"Before");
                while (xmlr.hasNext())
                {
                    write(xmlr, xmlWriter);
                    xmlr.next();
                }
                System.out.println(getMap().size()+"After");
            }
            catch(Exception e)
            {
                e.printStackTrace();
            }

        }

        public boolean accept(XMLStreamReader reader)
        {
            System.out.println(getMap().size()+"inside");
            if ( getMap().containsKey("Something") )
            {
                System.out.println("The value is there");
            }
            return true;
        }

        private void write(XMLStreamReader xmlr, XMLStreamWriter writer) throws XMLStreamException
        {
            switch (xmlr.getEventType()) {
                case XMLEvent.START_ELEMENT:
                    String localName = xmlr.getLocalName();
                    writer.writeStartElement(localName);
                break;
            }
        }   
    }

When I create the tagMap as static, it works, but since I will put this class in threads, all the maps will point to the same map, making the comparison useless. Specifically I have seen that inside the function accept, the map has 0 values.

The function accept is part of the interface SteamFilter, so it is called automatically when an event occurs. I have tried changing the map to public, and even setting the values with a constructor, but it is the same.

The way it is being called in the class that creates the class, is this:

    Runnable runClass = new Runnable(){
        public void run(){
            try
            {
                MyClass myC = new MyClass();
                myC.doSomething("value");
            }
            catch (Exception e)
            {
                e.printStackTrace();
            }
        }
    }
    Thread myTask = new Thread(runClass);
    myTask.start();

Do you know how can I check for the value of the map inside the function accept?

Answer 1

You instanciate your FilterReader with a new Instance of MyClass (one that hasn’t been called doSomething yet). If you instead start it with the same instance that is currently be worked on it should work.

Change:

xmlif.createFilteredReader(xmlif.createXMLStreamReader(fis),new MyClass())

to

xmlif.createFilteredReader(xmlif.createXMLStreamReader(fis),this)