AbstractMessageParser.java
- /* Copyright 2002-2022 CS GROUP
- * Licensed to CS GROUP (CS) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * CS 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.orekit.files.ccsds.utils.parsing;
- import java.io.IOException;
- import java.util.HashMap;
- import java.util.Map;
- import org.hipparchus.exception.LocalizedCoreFormats;
- import org.orekit.data.DataSource;
- import org.orekit.errors.OrekitException;
- import org.orekit.errors.OrekitInternalError;
- import org.orekit.files.ccsds.utils.FileFormat;
- import org.orekit.files.ccsds.utils.lexical.LexicalAnalyzerSelector;
- import org.orekit.files.ccsds.utils.lexical.MessageParser;
- import org.orekit.files.ccsds.utils.lexical.MessageVersionXmlTokenBuilder;
- import org.orekit.files.ccsds.utils.lexical.ParseToken;
- import org.orekit.files.ccsds.utils.lexical.XmlTokenBuilder;
- /** Parser for CCSDS messages.
- * <p>
- * Note than starting with Orekit 11.0, CCSDS message parsers are
- * mutable objects that gather the data being parsed, until the
- * message is complete and the {@link #parseMessage(org.orekit.data.DataSource)
- * parseMessage} method has returned. This implies that parsers
- * should <em>not</em> be used in a multi-thread context. The recommended
- * way to use parsers is to either dedicate one parser for each message
- * and drop it afterwards, or to use a single-thread loop.
- * </p>
- * @param <T> type of the file
- * @author Luc Maisonobe
- * @since 11.0
- */
- public abstract class AbstractMessageParser<T> implements MessageParser<T> {
- /** Safety limit for loop over processing states. */
- private static final int MAX_LOOP = 100;
- /** Root element for XML files. */
- private final String root;
- /** Key for format version. */
- private final String formatVersionKey;
- /** Anticipated next processing state. */
- private ProcessingState next;
- /** Current processing state. */
- private ProcessingState current;
- /** Fallback processing state. */
- private ProcessingState fallback;
- /** Format of the file ready to be parsed. */
- private FileFormat format;
- /** Flag for XML end tag. */
- private boolean endTagSeen;
- /** Simple constructor.
- * @param root root element for XML files
- * @param formatVersionKey key for format version
- */
- protected AbstractMessageParser(final String root, final String formatVersionKey) {
- this.root = root;
- this.formatVersionKey = formatVersionKey;
- this.current = null;
- setFallback(new ErrorState());
- }
- /** Set fallback processing state.
- * <p>
- * The fallback processing state is used if anticipated state fails
- * to parse the token.
- * </p>
- * @param fallback processing state to use if anticipated state does not work
- */
- public void setFallback(final ProcessingState fallback) {
- this.fallback = fallback;
- }
- /** Reset parser to initial state before parsing.
- * @param fileFormat format of the file ready to be parsed
- * @param initialState initial processing state
- */
- protected void reset(final FileFormat fileFormat, final ProcessingState initialState) {
- format = fileFormat;
- current = initialState;
- endTagSeen = false;
- anticipateNext(fallback);
- }
- /** Set the flag for XML end tag.
- * @param endTagSeen if true, the XML end tag has been seen
- */
- public void setEndTagSeen(final boolean endTagSeen) {
- this.endTagSeen = endTagSeen;
- }
- /** Check if XML end tag has been seen.
- * @return true if XML end tag has been seen
- */
- public boolean wasEndTagSeen() {
- return endTagSeen;
- }
- /** Get the current processing state.
- * @return current processing state
- */
- public ProcessingState getCurrent() {
- return current;
- }
- /** Get the file format.
- * @return file format
- */
- protected FileFormat getFileFormat() {
- return format;
- }
- /** {@inheritDoc} */
- @Override
- public T parseMessage(final DataSource source) {
- try {
- return LexicalAnalyzerSelector.select(source).accept(this);
- } catch (IOException ioe) {
- throw new OrekitException(ioe, LocalizedCoreFormats.SIMPLE_MESSAGE,
- ioe.getLocalizedMessage());
- }
- }
- /** {@inheritDoc} */
- @Override
- public String getFormatVersionKey() {
- return formatVersionKey;
- }
- /** {@inheritDoc} */
- @Override
- public Map<String, XmlTokenBuilder> getSpecialXmlElementsBuilders() {
- final HashMap<String, XmlTokenBuilder> builders = new HashMap<>();
- if (formatVersionKey != null) {
- // special handling of root tag that contains the format version
- builders.put(root, new MessageVersionXmlTokenBuilder());
- }
- return builders;
- }
- /** Anticipate what next processing state should be.
- * @param anticipated anticipated next processing state
- */
- public void anticipateNext(final ProcessingState anticipated) {
- this.next = anticipated;
- }
- /** {@inheritDoc} */
- @Override
- public void process(final ParseToken token) {
- // loop over the various states until one really processes the token
- for (int i = 0; i < MAX_LOOP; ++i) {
- if (current.processToken(token)) {
- return;
- }
- current = next;
- next = fallback;
- }
- // this should never happen
- throw new OrekitInternalError(null);
- }
- }