net.sf.saxon.pull.PullPushTee Maven / Gradle / Ivy

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package net.sf.saxon.pull;

import net.sf.saxon.event.Receiver;
import net.sf.saxon.event.SequenceReceiver;
import net.sf.saxon.om.AttributeCollection;
import net.sf.saxon.om.NamespaceDeclarations;
import net.sf.saxon.om.Orphan;
import net.sf.saxon.trans.XPathException;
import net.sf.saxon.type.Type;

import java.util.List;

/**
 * PullPushTee is a pass-through filter class that links one PullProvider to another PullProvider
 * in a pipeline, copying all events that are read into a push pipeline, supplied in the form
 * of a Receiver.
 *
 * This class can be used to insert a schema validator into a pull pipeline, since Saxon's schema
 * validation is push-based. It could also be used to insert a serializer into the pipeline, allowing
 * the XML document being "pulled" to be displayed for diagnostic purposes.
*/

public class PullPushTee extends PullFilter {

    private Receiver branch;
    boolean previousAtomic = false;

    /**
     * Create a PullPushTee
     * @param base the PullProvider to which requests are to be passed
     * @param branch the Receiver to which all events are to be copied, as "push" events
     */

    public PullPushTee(PullProvider base, Receiver branch) throws XPathException {
        super(base);
        this.branch = branch;
        //branch.open();
    }

    /**
     * Get the Receiver to which events are being tee'd.
     * @return the Receiver
     */

    public Receiver getReceiver() {
        return branch;
    }

    /**
     * Get the next event. This implementation gets the next event from the underlying PullProvider,
     * copies it to the branch Receiver, and then returns the event to the caller.
     *
     * @return an integer code indicating the type of event. The code
     *         {@link #END_OF_INPUT} is returned at the end of the sequence.
     */

    public int next() throws XPathException {
        currentEvent = super.next();
        copyEvent(currentEvent);
        return currentEvent;
    }


    /**
     * Copy a pull event to a Receiver
     * @param event the pull event to be copied
     */

    private void copyEvent(int event) throws XPathException {
        PullProvider in = getUnderlyingProvider();
        Receiver out = branch;
        switch (event) {
            case START_DOCUMENT:
                out.startDocument(0);
                break;

            case START_ELEMENT:
                out.startElement(in.getNameCode(), in.getTypeAnnotation(), 0, 0);

                NamespaceDeclarations decl = in.getNamespaceDeclarations();
                for (int i=0; i