org.n52.svalbard.encode.stream.xml.AbstractElementXmlStreamWriter Maven / Gradle / Ivy
/*
* Copyright 2016-2019 52°North Initiative for Geospatial Open Source
* Software GmbH
*
* 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.
*/
package org.n52.svalbard.encode.stream.xml;
import static java.util.stream.Collectors.joining;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.Reader;
import java.io.StringReader;
import java.io.Writer;
import java.net.URI;
import java.time.OffsetDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Collection;
import java.util.Iterator;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.function.Function;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamException;
import org.n52.iceland.util.XmlFactories;
import org.n52.shetland.ogc.gml.time.TimeInstant;
import org.n52.shetland.ogc.gml.time.TimePosition;
import org.n52.shetland.util.DateTimeHelper;
import org.n52.shetland.w3c.SchemaLocation;
import org.n52.shetland.w3c.W3CConstants;
import org.n52.shetland.w3c.xlink.Actuate;
import org.n52.shetland.w3c.xlink.Link;
import org.n52.shetland.w3c.xlink.Show;
import org.n52.svalbard.encode.exception.EncodingException;
import org.n52.svalbard.stream.XLinkConstants;
import com.google.common.base.Strings;
import com.google.common.escape.Escaper;
import com.google.common.io.BaseEncoding;
import com.google.common.io.ByteStreams;
import com.google.common.xml.XmlEscapers;
public abstract class AbstractElementXmlStreamWriter extends XmlFactories implements ElementXmlStreamWriter {
private static final Escaper ESCAPER = XmlEscapers.xmlContentEscaper();
private XmlStreamWritingContext context;
@Override
public void setContext(XmlStreamWritingContext context) {
this.context = Objects.requireNonNull(context);
}
protected XmlStreamWritingContext context() {
return this.context;
}
protected void attr(QName name,
String value) throws XMLStreamException {
context().dispatch(eventFactory().createAttribute(name, value));
}
protected void attr(QName name,
Optional value) throws XMLStreamException {
if (value.isPresent()) {
attr(name, value.get());
}
}
protected void attr(String name,
Optional value) throws XMLStreamException {
attr(new QName(name), value);
}
protected void attr(String name,
String value) throws XMLStreamException {
attr(new QName(name), value);
}
protected void attr(QName name,
Collection coll,
Function mapper) throws XMLStreamException {
if (coll != null && !coll.isEmpty()) {
attr(name, coll.stream().map(mapper).collect(joining(" ")));
}
}
protected void attr(String namespace,
String localName,
String value) throws XMLStreamException {
attr(new QName(namespace, localName), value);
}
protected void attr(String name,
Collection coll,
Function mapper) throws XMLStreamException {
attr(new QName(name), coll, mapper);
}
protected void namespace(String prefix,
String namespace) throws XMLStreamException {
if (context().declareNamespace(prefix, namespace)) {
context().dispatch(eventFactory().createNamespace(prefix, namespace));
}
}
protected void start(String namespace,
String localName) throws XMLStreamException {
start(new QName(namespace, localName));
}
protected void start(String namespace,
String localName,
String prefix) throws XMLStreamException {
start(new QName(namespace, localName, prefix));
}
protected void start(QName name) throws XMLStreamException {
context().dispatch(eventFactory().createStartElement(name.getPrefix(), name.getNamespaceURI(), name
.getLocalPart()));
}
protected void empty(QName name) throws XMLStreamException {
start(name);
end(name);
}
protected void chars(String chars) throws XMLStreamException {
context().dispatch(eventFactory().createCharacters(chars));
}
protected void chars(String chars,
boolean escape) throws XMLStreamException {
// TODO escape by default
context().dispatch(eventFactory().createCharacters(escape ? escaper().escape(chars) : chars));
}
protected void end(QName name) throws XMLStreamException {
context().dispatch(eventFactory().createEndElement(name.getPrefix(), name.getNamespaceURI(), name
.getLocalPart()));
}
protected void write(Reader in) throws XMLStreamException {
context().write(in);
}
protected void write(XMLEventReader reader) throws XMLStreamException {
context().write(reader);
}
protected void flush() throws XMLStreamException {
context().flush();
}
protected void cdata(String value) throws XMLStreamException {
context().dispatch(eventFactory().createCData(value));
}
protected void writeBase64(InputStream data) throws IOException {
try (CharacterEmittingWriter writer = new CharacterEmittingWriter();
OutputStream encodingStream = base64().encodingStream(writer)) {
ByteStreams.copy(data, encodingStream);
}
}
/**
* Write {@link TimeInstant} to stream
*
* @param time
* {@link TimeInstant} to write to stream
*
* @throws XMLStreamException
* If an error occurs when writing to {@link OutputStream}
*/
protected void time(TimeInstant time) throws XMLStreamException {
time(time.getTimePosition());
}
/**
* Write {@link TimePosition} as ISO 8601 to stream
*
* @param time
* {@link TimePosition} to write as ISO 8601 to stream
*
* @throws XMLStreamException
* If an error occurs when writing to {@link OutputStream}
*/
protected void time(TimePosition time) throws XMLStreamException {
chars(DateTimeHelper.formatDateTime2IsoString(time.getTime()));
}
/**
* Write {@link SchemaLocation}s as xsi:schemaLocations attribute to stream
*
* @param schemaLocations
* {@link SchemaLocation}s to write
*
* @throws XMLStreamException
* If an error occurs when writing to {@link OutputStream}
*/
protected void schemaLocation(Set schemaLocations) throws XMLStreamException {
String merged = mergeSchemaLocationsToString(schemaLocations);
if (!Strings.isNullOrEmpty(merged)) {
namespace(W3CConstants.NS_XSI_PREFIX, W3CConstants.NS_XSI);
attr(W3CConstants.QN_SCHEMA_LOCATION_PREFIXED, merged);
}
}
protected void writeXLinkAttrs(Link link) throws XMLStreamException {
namespace(XLinkConstants.NS_XLINK_PREFIX, XLinkConstants.NS_XLINK);
attr(XLinkConstants.Attr.QN_HREF, link.getHref().map(URI::toString));
attr(XLinkConstants.Attr.QN_ROLE, link.getRole().map(URI::toString));
attr(XLinkConstants.Attr.QN_SHOW, link.getShow().map(Show::toString));
attr(XLinkConstants.Attr.QN_TITLE, link.getTitle());
attr(XLinkConstants.Attr.QN_ARCROLE, link.getArcrole().map(URI::toString));
attr(XLinkConstants.Attr.QN_ACTUATE, link.getActuate().map(Actuate::toString));
}
protected void writeLink(QName name,
Link link) throws XMLStreamException {
element(name, link, this::writeXLinkAttrs);
}
protected void element(QName name,
String value) throws XMLStreamException {
start(name);
chars(value);
end(name);
}
protected void element(QName name,
Optional value) throws XMLStreamException {
if (value.isPresent()) {
element(name, value.get());
}
}
protected void element(QName name,
OffsetDateTime time) throws XMLStreamException {
element(name, format(time));
}
protected void element(QName name,
Optional elem,
ElementWriter writer) throws XMLStreamException {
if (elem.isPresent()) {
start(name);
writer.write(elem.get());
end(name);
}
}
protected void element(QName name,
T elem,
ElementWriter writer) throws XMLStreamException {
if (elem != null) {
start(name);
writer.write(elem);
end(name);
}
}
protected void element(QName name,
ContentWriter writer) throws XMLStreamException {
start(name);
writer.write();
end(name);
}
protected void delegate(T object) throws XMLStreamException, EncodingException {
context().write(object);
}
protected String format(OffsetDateTime time) {
return DateTimeFormatter.ISO_DATE_TIME.format(time);
}
protected void forEach(QName name,
Iterable elements,
ElementWriter writer) throws XMLStreamException {
if (elements != null) {
for (T elem : elements) {
start(name);
writer.write(elem);
end(name);
}
}
}
protected void writeXML(String xml) throws XMLStreamException {
try (StringReader reader = new StringReader(xml)) {
write(reader);
}
}
protected static BaseEncoding base64() {
return BaseEncoding.base64().withSeparator("\n", 80);
}
private static String mergeSchemaLocationsToString(Iterable schemaLocations) {
if (schemaLocations == null) {
return "";
}
StringBuilder builder = new StringBuilder();
Iterator it = schemaLocations.iterator();
if (it.hasNext()) {
builder.append(it.next().getSchemaLocationString());
while (it.hasNext()) {
builder.append(" ").append(it.next().getSchemaLocationString());
}
}
return builder.toString();
}
/**
* @return the xmlContentEscaper
*/
protected static Escaper escaper() {
return ESCAPER;
}
@FunctionalInterface
protected interface ElementWriter {
void write(T elem) throws XMLStreamException;
}
@FunctionalInterface
protected interface ContentWriter {
void write() throws XMLStreamException;
}
private class CharacterEmittingWriter extends Writer {
private boolean closed;
@Override
public void write(char[] cbuf,
int off,
int len) throws IOException {
checkNotClosed();
write(new String(cbuf, off, len));
}
@Override
public void write(String str) throws IOException {
checkNotClosed();
try {
AbstractElementXmlStreamWriter.this.chars(str);
} catch (XMLStreamException ex) {
throw new IOException(ex);
}
}
@Override
public void write(String str,
int off,
int len) throws IOException {
checkNotClosed();
write(str.substring(off, len));
}
@Override
public void flush() throws IOException {
checkNotClosed();
try {
AbstractElementXmlStreamWriter.this.flush();
} catch (XMLStreamException ex) {
throw new IOException(ex);
}
}
@Override
public void close() {
this.closed = true;
}
private void checkNotClosed() throws IOException {
if (closed) {
throw new IOException("already closed");
}
}
}
}
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