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/**
* Copyright (c) 2008, SnakeYAML
*
* 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.pyyaml;
import java.util.ArrayList;
import org.yaml.snakeyaml.DumperOptions;
import org.yaml.snakeyaml.DumperOptions.Version;
import org.yaml.snakeyaml.events.AliasEvent;
import org.yaml.snakeyaml.events.DocumentEndEvent;
import org.yaml.snakeyaml.events.DocumentStartEvent;
import org.yaml.snakeyaml.events.Event;
import org.yaml.snakeyaml.events.ImplicitTuple;
import org.yaml.snakeyaml.events.MappingEndEvent;
import org.yaml.snakeyaml.events.MappingStartEvent;
import org.yaml.snakeyaml.events.ScalarEvent;
import org.yaml.snakeyaml.events.SequenceEndEvent;
import org.yaml.snakeyaml.events.SequenceStartEvent;
import org.yaml.snakeyaml.events.StreamEndEvent;
import org.yaml.snakeyaml.events.StreamStartEvent;
import org.yaml.snakeyaml.nodes.Tag;
import org.yaml.snakeyaml.parser.Parser;
import org.yaml.snakeyaml.tokens.AliasToken;
import org.yaml.snakeyaml.tokens.AnchorToken;
import org.yaml.snakeyaml.tokens.ScalarToken;
import org.yaml.snakeyaml.tokens.TagToken;
import org.yaml.snakeyaml.tokens.Token;
public class CanonicalParser implements Parser {
private final ArrayList<Event> events;
private boolean parsed;
private final CanonicalScanner scanner;
public CanonicalParser(String data) {
events = new ArrayList<Event>();
parsed = false;
scanner = new CanonicalScanner(data);
}
// stream: STREAM-START document* STREAM-END
private void parseStream() {
scanner.getToken(Token.ID.StreamStart);
events.add(new StreamStartEvent(null, null));
while (!scanner.checkToken(Token.ID.StreamEnd)) {
if (scanner.checkToken(Token.ID.Directive, Token.ID.DocumentStart)) {
parseDocument();
} else {
throw new CanonicalException("document is expected, got " + scanner.tokens.get(0));
}
}
scanner.getToken(Token.ID.StreamEnd);
events.add(new StreamEndEvent(null, null));
}
// document: DIRECTIVE? DOCUMENT-START node
private void parseDocument() {
if (scanner.checkToken(Token.ID.Directive)) {
scanner.getToken(Token.ID.Directive);
}
scanner.getToken(Token.ID.DocumentStart);
events.add(new DocumentStartEvent(null, null, true, Version.V1_1, null));
parseNode();
events.add(new DocumentEndEvent(null, null, true));
}
// node: ALIAS | ANCHOR? TAG? (SCALAR|sequence|mapping)
private void parseNode() {
if (scanner.checkToken(Token.ID.Alias)) {
AliasToken token = (AliasToken) scanner.getToken();
events.add(new AliasEvent(token.getValue(), null, null));
} else {
String anchor = null;
if (scanner.checkToken(Token.ID.Anchor)) {
AnchorToken token = (AnchorToken) scanner.getToken();
anchor = token.getValue();
}
String tag = null;
if (scanner.checkToken(Token.ID.Tag)) {
TagToken token = (TagToken) scanner.getToken();
tag = token.getValue().getHandle() + token.getValue().getSuffix();
}
if (scanner.checkToken(Token.ID.Scalar)) {
ScalarToken token = (ScalarToken) scanner.getToken();
events.add(new ScalarEvent(anchor, tag, new ImplicitTuple(false, false), token.getValue(),
null, null, DumperOptions.ScalarStyle.PLAIN));
} else if (scanner.checkToken(Token.ID.FlowSequenceStart)) {
events.add(new SequenceStartEvent(anchor, Tag.SEQ.getValue(), false, null, null,
DumperOptions.FlowStyle.AUTO));
parseSequence();
} else if (scanner.checkToken(Token.ID.FlowMappingStart)) {
events.add(new MappingStartEvent(anchor, Tag.MAP.getValue(), false, null, null,
DumperOptions.FlowStyle.AUTO));
parseMapping();
} else {
throw new CanonicalException(
"SCALAR, '[', or '{' is expected, got " + scanner.tokens.get(0));
}
}
}
// sequence: SEQUENCE-START (node (ENTRY node)*)? ENTRY? SEQUENCE-END
private void parseSequence() {
scanner.getToken(Token.ID.FlowSequenceStart);
if (!scanner.checkToken(Token.ID.FlowSequenceEnd)) {
parseNode();
while (!scanner.checkToken(Token.ID.FlowSequenceEnd)) {
scanner.getToken(Token.ID.FlowEntry);
if (!scanner.checkToken(Token.ID.FlowSequenceEnd)) {
parseNode();
}
}
}
scanner.getToken(Token.ID.FlowSequenceEnd);
events.add(new SequenceEndEvent(null, null));
}
// mapping: MAPPING-START (map_entry (ENTRY map_entry)*)? ENTRY? MAPPING-END
private void parseMapping() {
scanner.getToken(Token.ID.FlowMappingStart);
if (!scanner.checkToken(Token.ID.FlowMappingEnd)) {
parseMapEntry();
while (!scanner.checkToken(Token.ID.FlowMappingEnd)) {
scanner.getToken(Token.ID.FlowEntry);
if (!scanner.checkToken(Token.ID.FlowMappingEnd)) {
parseMapEntry();
}
}
}
scanner.getToken(Token.ID.FlowMappingEnd);
events.add(new MappingEndEvent(null, null));
}
// map_entry: KEY node VALUE node
private void parseMapEntry() {
scanner.getToken(Token.ID.Key);
parseNode();
scanner.getToken(Token.ID.Value);
parseNode();
}
public void parse() {
parseStream();
parsed = true;
}
public Event getEvent() {
if (!parsed) {
parse();
}
return events.remove(0);
}
/**
* Check the type of the next event.
*/
public boolean checkEvent(Event.ID choice) {
if (!parsed) {
parse();
}
if (!events.isEmpty()) {
return events.get(0).is(choice);
}
return false;
}
/**
* Get the next event.
*/
public Event peekEvent() {
if (!parsed) {
parse();
}
if (events.isEmpty()) {
return null;
} else {
return events.get(0);
}
}
}
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