/*
* Copyright (c) 2014 Red Hat, Inc. and/or its affiliates.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Cheng Fang - Initial API and implementation
*/
package org.jberet.support.io;
import java.io.Serializable;
import javax.batch.api.BatchProperty;
import javax.batch.api.chunk.ItemReader;
import javax.enterprise.context.Dependent;
import javax.inject.Inject;
import javax.inject.Named;
import com.fasterxml.jackson.core.JsonToken;
import com.fasterxml.jackson.core.io.InputDecorator;
import com.fasterxml.jackson.dataformat.xml.JacksonXmlModule;
import com.fasterxml.jackson.dataformat.xml.deser.FromXmlParser;
import org.jberet.support._private.SupportLogger;
/**
* An implementation of {@code javax.batch.api.chunk.ItemReader} that reads a collection of data from XML resource.
* Users of this class should provide a bean class that represents individual data item in the source XML, and the
* {@link #readItem()} method reads one item at a time and binds it to the provided bean type.
*/
@Named
@Dependent
public class XmlItemReader extends XmlItemReaderWriterBase implements ItemReader {
@Inject
@BatchProperty
protected Class beanType;
@Inject
@BatchProperty
protected int start;
@Inject
@BatchProperty
protected int end;
@Inject
@BatchProperty
protected Class inputDecorator;
@Inject
@BatchProperty
protected String xmlTextElementName;
private FromXmlParser fromXmlParser;
private JsonToken token;
private int rowNumber;
@Override
public void open(final Serializable checkpoint) throws Exception {
if (end == 0) {
end = Integer.MAX_VALUE;
}
if (checkpoint != null) {
start = (Integer) checkpoint;
}
if (start > end) {
throw SupportLogger.LOGGER.invalidStartPosition((Integer) checkpoint, start, end);
}
super.initXmlFactory();
if (inputDecorator != null) {
xmlFactory.setInputDecorator((InputDecorator) inputDecorator.newInstance());
}
fromXmlParser = (FromXmlParser) xmlFactory.createParser(getInputStream(false));
SupportLogger.LOGGER.openingResource(resource, this.getClass());
token = fromXmlParser.nextToken();
}
@Override
public Object readItem() throws Exception {
if (rowNumber >= end) {
return null;
}
int nestedObjectLevel = 0;
do {
token = fromXmlParser.nextToken();
if (token == null) {
return null;
} else if (token == JsonToken.START_OBJECT) {
nestedObjectLevel++;
if (nestedObjectLevel == 1) {
rowNumber++;
} else if (nestedObjectLevel < 1) {
throw SupportLogger.LOGGER.unexpectedJsonContent(fromXmlParser.getCurrentLocation());
}
if (rowNumber >= start) {
break;
}
} else if (token == JsonToken.END_OBJECT) {
nestedObjectLevel--;
}
} while (true);
return xmlMapper.readValue(fromXmlParser, beanType);
}
@Override
public Serializable checkpointInfo() throws Exception {
return rowNumber;
}
@Override
public void close() throws Exception {
if (fromXmlParser != null) {
SupportLogger.LOGGER.closingResource(resource, this.getClass());
fromXmlParser.close();
fromXmlParser = null;
}
}
@Override
protected void initXmlModule() {
if (xmlTextElementName != null && !xmlTextElementName.isEmpty()) {
xmlModule = new JacksonXmlModule();
xmlModule.setXMLTextElementName(xmlTextElementName);
}
}
}