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/*-
* ============LICENSE_START=======================================================
* Copyright (C) 2016-2018 Ericsson. All rights reserved.
* Modifications Copyright (C) 2019-2021 Nordix Foundation.
* ================================================================================
* 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
*
* 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.
*
* SPDX-License-Identifier: Apache-2.0
* ============LICENSE_END=========================================================
*/
package org.onap.policy.apex.model.basicmodel.handling;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Set;
import java.util.TreeSet;
import javax.xml.XMLConstants;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.OutputKeys;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import org.eclipse.persistence.jaxb.JAXBContextFactory;
import org.eclipse.persistence.jaxb.MarshallerProperties;
import org.eclipse.persistence.oxm.MediaType;
import org.onap.policy.apex.model.basicmodel.concepts.AxConcept;
import org.onap.policy.apex.model.basicmodel.concepts.AxValidationResult;
import org.onap.policy.common.utils.validation.Assertions;
import org.slf4j.ext.XLogger;
import org.slf4j.ext.XLoggerFactory;
/**
* This class writes an Apex concept to an XML file or JSON file from a Java Apex Concept.
*
* @param <C> the type of Apex concept to write, must be a sub class of {@link AxConcept}
* @author John Keeney (john.keeney@ericsson.com)
*/
public class ApexModelWriter<C extends AxConcept> {
private static final String CONCEPT_MAY_NOT_BE_NULL = "concept may not be null";
private static final String CONCEPT_WRITER_MAY_NOT_BE_NULL = "concept writer may not be null";
private static final String CONCEPT_STREAM_MAY_NOT_BE_NULL = "concept stream may not be null";
// Get a reference to the logger
private static final XLogger LOGGER = XLoggerFactory.getXLogger(ApexModelWriter.class);
// Writing as JSON or XML
private boolean jsonOutput = false;
// The list of fields to output as CDATA
private final Set<String> cdataFieldSet = new TreeSet<>();
// The Marshaller for the Apex concepts
private Marshaller marshaller = null;
// All written concepts are validated before writing if this flag is set
private boolean validateFlag = true;
/**
* Constructor, initiates the writer.
*
* @param rootConceptClass the root concept class for concept reading
* @throws ApexModelException the apex concept writer exception
*/
public ApexModelWriter(final Class<C> rootConceptClass) throws ApexModelException {
// Set up Eclipselink for XML and JSON output
System.setProperty("javax.xml.bind.context.factory", "org.eclipse.persistence.jaxb.JAXBContextFactory");
try {
final var jaxbContext = JAXBContextFactory.createContext(new Class[]{rootConceptClass}, null);
// Set up the unmarshaller to carry out validation
marshaller = jaxbContext.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.setEventHandler(new javax.xml.bind.helpers.DefaultValidationEventHandler());
} catch (final JAXBException e) {
throw new ApexModelException("JAXB marshaller creation exception", e);
}
}
/**
* The set of fields to be output as CDATA.
*
* @return the set of fields
*/
public Set<String> getCDataFieldSet() {
return cdataFieldSet;
}
/**
* Return true if JSON output enabled, XML output if false.
*
* @return true for JSON output
*/
public boolean isJsonOutput() {
return jsonOutput;
}
/**
* Set the value of JSON output, true for JSON output, false for XML output.
*
* @param jsonOutput true for JSON output
* @throws ApexModelException on errors setting output type
*/
public void setJsonOutput(final boolean jsonOutput) throws ApexModelException {
this.jsonOutput = jsonOutput;
// Set up output specific parameters
if (this.jsonOutput) {
try {
marshaller.setProperty(MarshallerProperties.MEDIA_TYPE, MediaType.APPLICATION_JSON);
marshaller.setProperty(MarshallerProperties.JSON_INCLUDE_ROOT, true);
} catch (final Exception e) {
throw new ApexModelException("JAXB error setting marshaller for JSON output", e);
}
} else {
try {
marshaller.setProperty(MarshallerProperties.MEDIA_TYPE, MediaType.APPLICATION_XML);
} catch (final Exception e) {
throw new ApexModelException("JAXB error setting marshaller for XML output", e);
}
}
}
/**
* This method validates the Apex concept then writes it into a stream.
*
* @param concept the concept to write
* @param apexConceptStream the stream to write to
* @throws ApexModelException on validation or writing exceptions
*/
public void write(final C concept, final OutputStream apexConceptStream) throws ApexModelException {
Assertions.argumentNotNull(concept, CONCEPT_MAY_NOT_BE_NULL);
Assertions.argumentNotNull(apexConceptStream, CONCEPT_STREAM_MAY_NOT_BE_NULL);
this.write(concept, new OutputStreamWriter(apexConceptStream));
}
/**
* This method validates the Apex concept then writes it into a writer.
*
* @param concept the concept to write
* @param apexConceptWriter the writer to write to
* @throws ApexModelException on validation or writing exceptions
*/
public void write(final C concept, final Writer apexConceptWriter) throws ApexModelException {
Assertions.argumentNotNull(concept, CONCEPT_MAY_NOT_BE_NULL);
Assertions.argumentNotNull(apexConceptWriter, CONCEPT_WRITER_MAY_NOT_BE_NULL);
// Check if we should validate the concept
if (validateFlag) {
// Validate the concept first
final AxValidationResult validationResult = concept.validate(new AxValidationResult());
if (!validationResult.isValid()) {
String message =
"Apex concept xml (" + concept.getKey().getId() + ") validation failed: " + validationResult
.toString();
throw new ApexModelException(message);
}
}
if (jsonOutput) {
writeJson(concept, apexConceptWriter);
} else {
writeXml(concept, apexConceptWriter);
}
}
/**
* This method writes the Apex concept into a writer in XML format.
*
* @param concept the concept to write
* @param apexConceptWriter the writer to write to
* @throws ApexModelException on validation or writing exceptions
*/
private void writeXml(final C concept, final Writer apexConceptWriter) throws ApexModelException {
Assertions.argumentNotNull(concept, CONCEPT_MAY_NOT_BE_NULL);
LOGGER.debug("writing Apex concept XML . . .");
try {
// Write the concept into a DOM document, then transform to add CDATA fields and pretty
// print, then write out the result
final var docBuilderFactory = DocumentBuilderFactory.newInstance();
docBuilderFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
docBuilderFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_SCHEMA, "");
docBuilderFactory.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);
final var document = docBuilderFactory.newDocumentBuilder().newDocument();
// Marshal the concept into the empty document.
marshaller.marshal(concept, document);
final var domTransformer = getTransformer();
// Convert the cDataFieldSet into a space delimited string
domTransformer.setOutputProperty(OutputKeys.CDATA_SECTION_ELEMENTS,
cdataFieldSet.toString().replaceAll("[\\[\\]\\,]", " "));
domTransformer.transform(new DOMSource(document), new StreamResult(apexConceptWriter));
} catch (JAXBException | TransformerException | ParserConfigurationException e) {
throw new ApexModelException("Unable to marshal Apex concept to XML", e);
}
LOGGER.debug("wrote Apex concept XML");
}
private Transformer getTransformer() throws TransformerConfigurationException {
// Transform the DOM to the output stream
final var transformerFactory = TransformerFactory.newInstance();
transformerFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_DTD, "");
transformerFactory.setAttribute(XMLConstants.ACCESS_EXTERNAL_STYLESHEET, "");
final var domTransformer = transformerFactory.newTransformer();
// Pretty print
try {
domTransformer.setOutputProperty(OutputKeys.INDENT, "yes");
// May fail if not using XALAN XSLT engine. But not in any way vital
domTransformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2");
} catch (final Exception ignore) {
LOGGER.trace("Unable to set indent property", ignore);
}
return domTransformer;
}
/**
* This method writes the Apex concept into a writer in JSON format.
*
* @param concept the concept to write
* @param apexConceptWriter the writer to write to
* @throws ApexModelException on validation or writing exceptions
*/
private void writeJson(final C concept, final Writer apexConceptWriter) throws ApexModelException {
Assertions.argumentNotNull(concept, CONCEPT_MAY_NOT_BE_NULL);
LOGGER.debug("writing Apex concept JSON . . .");
try {
marshaller.marshal(concept, apexConceptWriter);
} catch (final JAXBException e) {
throw new ApexModelException("Unable to marshal Apex concept to JSON", e);
}
LOGGER.debug("wrote Apex concept JSON");
}
/**
* Gets the validation flag value.
*
* @return the validation flag value
*/
public boolean getValidateFlag() {
return validateFlag;
}
/**
* Sets the validation flag.
*
* @param validateFlag the validation flag value
*/
public void setValidateFlag(final boolean validateFlag) {
this.validateFlag = validateFlag;
}
}
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