org.apache.olingo.fit.utils.XMLEventReaderWrapper.java Source code

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Here is the source code for org.apache.olingo.fit.utils.XMLEventReaderWrapper.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.olingo.fit.utils;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.Charset;

import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.XMLEvent;

import org.apache.commons.io.IOUtils;

public class XMLEventReaderWrapper implements XMLEventReader {

    private static final Charset ENCODING = Charset.forName(org.apache.olingo.commons.api.Constants.UTF8);

    public final static String CONTENT = "CONTENT_TAG";

    public final String CONTENT_STAG;

    public final static String CONTENT_ETAG = "</" + CONTENT + ">";

    private final XMLEventReader wrapped;

    private XMLEvent nextGivenEvent = null;

    public XMLEventReaderWrapper(final InputStream stream) throws IOException, XMLStreamException {
        final StringBuilder startBuilder = new StringBuilder();
        startBuilder.append("<").append(CONTENT).append(" xmlns:m").append("=\"")
                .append(Constants.get(ConstantKey.METADATA_NS)).append("\"").append(" xmlns:d").append("=\"")
                .append(Constants.get(ConstantKey.DATASERVICES_NS)).append("\"").append(" xmlns:georss")
                .append("=\"").append(Constants.get(ConstantKey.GEORSS_NS)).append("\"").append(" xmlns:gml")
                .append("=\"").append(Constants.get(ConstantKey.GML_NS)).append("\"").append(">");

        CONTENT_STAG = startBuilder.toString();

        final XMLInputFactory factory = XMLInputFactory.newInstance();

        final InputStreamReader reader = new InputStreamReader(new ByteArrayInputStream(
                (CONTENT_STAG + IOUtils.toString(stream, ENCODING).replaceAll("^<\\?xml.*\\?>", "")
                        + XMLEventReaderWrapper.CONTENT_ETAG).getBytes(ENCODING)),
                Constants.DECODER);

        wrapped = factory.createXMLEventReader(reader);

        init();
    }

    private void init() {

        try {
            do {

                nextGivenEvent = wrapped.nextEvent();

            } while (nextGivenEvent.isStartDocument() || (nextGivenEvent.isStartElement()
                    && CONTENT.equals(nextGivenEvent.asStartElement().getName().getLocalPart())));

        } catch (Exception ignore) {
            // ignore
        }
    }

    @Override
    public XMLEvent nextEvent() throws XMLStreamException {
        final XMLEvent event = nextGivenEvent;

        if (!isValidEvent(event)) {
            throw new IllegalStateException("No event found");
        }

        nextGivenEvent = wrapped.hasNext() ? wrapped.nextEvent() : null;

        return event;
    }

    @Override
    public boolean hasNext() {
        return isValidEvent(nextGivenEvent);
    }

    @Override
    public XMLEvent peek() throws XMLStreamException {
        return wrapped.peek();
    }

    @Override
    public String getElementText() throws XMLStreamException {
        return wrapped.getElementText();
    }

    @Override
    public XMLEvent nextTag() throws XMLStreamException {
        XMLEvent tagEvent = wrapped.nextTag();
        if (isValidEvent(tagEvent)) {
            return tagEvent;
        } else {
            return null;
        }
    }

    @Override
    public Object getProperty(final String string) throws IllegalArgumentException {
        return wrapped.getProperty(string);
    }

    @Override
    public void close() throws XMLStreamException {
        wrapped.close();
    }

    @Override
    public Object next() {
        return wrapped.next();
    }

    @Override
    public void remove() {
        wrapped.remove();
    }

    private boolean isValidEvent(final XMLEvent event) {
        // discard content end element tag ...
        return event != null
                && (!event.isEndElement() || !CONTENT.equals(event.asEndElement().getName().getLocalPart()));
    }
}