org.springframework.batch.item.xml.stax.UnopenedElementClosingEventWriter.java Source code

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Here is the source code for org.springframework.batch.item.xml.stax.UnopenedElementClosingEventWriter.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * Licensed 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
 *
 *      https://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.springframework.batch.item.xml.stax;

import java.io.IOException;
import java.io.Writer;
import java.util.LinkedList;
import java.util.List;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.events.XMLEvent;

import org.springframework.dao.DataAccessResourceFailureException;
import org.springframework.util.StringUtils;

/**
 * Delegating XMLEventWriter, which writes EndElement events that match a given collection of QNames directly
 * to the underlying java.io.Writer instead of to the delegate XMLEventWriter.
 *
 * @author Jimmy Praet
 * @since 3.0
 */
public class UnopenedElementClosingEventWriter extends AbstractEventWriterWrapper {

    private LinkedList<QName> unopenedElements;

    private Writer ioWriter;

    public UnopenedElementClosingEventWriter(XMLEventWriter wrappedEventWriter, Writer ioWriter,
            List<QName> unopenedElements) {
        super(wrappedEventWriter);
        this.unopenedElements = new LinkedList<>(unopenedElements);
        this.ioWriter = ioWriter;
    }

    /* (non-Javadoc)
     * @see org.springframework.batch.item.xml.stax.AbstractEventWriterWrapper#add(javax.xml.stream.events.XMLEvent)
     */
    @Override
    public void add(XMLEvent event) throws XMLStreamException {
        if (isUnopenedElementCloseEvent(event)) {
            QName element = unopenedElements.removeLast();
            String nsPrefix = !StringUtils.hasText(element.getPrefix()) ? "" : element.getPrefix() + ":";
            try {
                super.flush();
                ioWriter.write("</" + nsPrefix + element.getLocalPart() + ">");
                ioWriter.flush();
            } catch (IOException ioe) {
                throw new DataAccessResourceFailureException("Unable to close tag: " + element, ioe);
            }
        } else {
            super.add(event);
        }
    }

    private boolean isUnopenedElementCloseEvent(XMLEvent event) {
        if (unopenedElements.isEmpty()) {
            return false;
        } else if (!event.isEndElement()) {
            return false;
        } else {
            return unopenedElements.getLast().equals(event.asEndElement().getName());
        }
    }

}