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16 package org.yaml.snakeyaml.composer;
17
18 import java.util.ArrayList;
19 import java.util.HashMap;
20 import java.util.HashSet;
21 import java.util.List;
22 import java.util.Map;
23 import java.util.Set;
24
25 import org.yaml.snakeyaml.events.AliasEvent;
26 import org.yaml.snakeyaml.events.Event;
27 import org.yaml.snakeyaml.events.MappingStartEvent;
28 import org.yaml.snakeyaml.events.NodeEvent;
29 import org.yaml.snakeyaml.events.ScalarEvent;
30 import org.yaml.snakeyaml.events.SequenceStartEvent;
31 import org.yaml.snakeyaml.nodes.MappingNode;
32 import org.yaml.snakeyaml.nodes.Node;
33 import org.yaml.snakeyaml.nodes.NodeId;
34 import org.yaml.snakeyaml.nodes.NodeTuple;
35 import org.yaml.snakeyaml.nodes.ScalarNode;
36 import org.yaml.snakeyaml.nodes.SequenceNode;
37 import org.yaml.snakeyaml.nodes.Tag;
38 import org.yaml.snakeyaml.parser.Parser;
39 import org.yaml.snakeyaml.resolver.Resolver;
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46
47
48 public class Composer {
49 private final Parser parser;
50 private final Resolver resolver;
51 private final Map<String, Node> anchors;
52 private final Set<Node> recursiveNodes;
53
54 public Composer(Parser parser, Resolver resolver) {
55 this.parser = parser;
56 this.resolver = resolver;
57 this.anchors = new HashMap<String, Node>();
58 this.recursiveNodes = new HashSet<Node>();
59 }
60
61
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63
64
65
66 public boolean checkNode() {
67
68 if (parser.checkEvent(Event.ID.StreamStart)) {
69 parser.getEvent();
70 }
71
72 return !parser.checkEvent(Event.ID.StreamEnd);
73 }
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81 public Node getNode() {
82
83 if (!parser.checkEvent(Event.ID.StreamEnd)) {
84 return composeDocument();
85 } else {
86 return null;
87 }
88 }
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98
99 public Node getSingleNode() {
100
101 parser.getEvent();
102
103 Node document = null;
104 if (!parser.checkEvent(Event.ID.StreamEnd)) {
105 document = composeDocument();
106 }
107
108 if (!parser.checkEvent(Event.ID.StreamEnd)) {
109 Event event = parser.getEvent();
110 throw new ComposerException("expected a single document in the stream",
111 document.getStartMark(), "but found another document", event.getStartMark());
112 }
113
114 parser.getEvent();
115 return document;
116 }
117
118 private Node composeDocument() {
119
120 parser.getEvent();
121
122 Node node = composeNode(null);
123
124 parser.getEvent();
125 this.anchors.clear();
126 recursiveNodes.clear();
127 return node;
128 }
129
130 private Node composeNode(Node parent) {
131 recursiveNodes.add(parent);
132 if (parser.checkEvent(Event.ID.Alias)) {
133 AliasEvent event = (AliasEvent) parser.getEvent();
134 String anchor = event.getAnchor();
135 if (!anchors.containsKey(anchor)) {
136 throw new ComposerException(null, null, "found undefined alias " + anchor,
137 event.getStartMark());
138 }
139 Node result = anchors.get(anchor);
140 if (recursiveNodes.remove(result)) {
141 result.setTwoStepsConstruction(true);
142 }
143 return result;
144 }
145 NodeEvent event = (NodeEvent) parser.peekEvent();
146 String anchor = null;
147 anchor = event.getAnchor();
148 if (anchor != null && anchors.containsKey(anchor)) {
149 throw new ComposerException("found duplicate anchor " + anchor + "; first occurence",
150 this.anchors.get(anchor).getStartMark(), "second occurence",
151 event.getStartMark());
152 }
153 Node node = null;
154 if (parser.checkEvent(Event.ID.Scalar)) {
155 node = composeScalarNode(anchor);
156 } else if (parser.checkEvent(Event.ID.SequenceStart)) {
157 node = composeSequenceNode(anchor);
158 } else {
159 node = composeMappingNode(anchor);
160 }
161 recursiveNodes.remove(parent);
162 return node;
163 }
164
165 private Node composeScalarNode(String anchor) {
166 ScalarEvent ev = (ScalarEvent) parser.getEvent();
167 String tag = ev.getTag();
168 boolean resolved = false;
169 Tag nodeTag;
170 if (tag == null || tag.equals("!")) {
171 nodeTag = resolver.resolve(NodeId.scalar, ev.getValue(), ev.getImplicit()
172 .canOmitTagInPlainScalar());
173 resolved = true;
174 } else {
175 nodeTag = new Tag(tag);
176 }
177 Node node = new ScalarNode(nodeTag, resolved, ev.getValue(), ev.getStartMark(),
178 ev.getEndMark(), ev.getStyle());
179 if (anchor != null) {
180 anchors.put(anchor, node);
181 }
182 return node;
183 }
184
185 private Node composeSequenceNode(String anchor) {
186 SequenceStartEvent startEvent = (SequenceStartEvent) parser.getEvent();
187 String tag = startEvent.getTag();
188 Tag nodeTag;
189 boolean resolved = false;
190 if (tag == null || tag.equals("!")) {
191 nodeTag = resolver.resolve(NodeId.sequence, null, startEvent.getImplicit());
192 resolved = true;
193 } else {
194 nodeTag = new Tag(tag);
195 }
196 final ArrayList<Node> children = new ArrayList<Node>();
197 SequenceNode node = new SequenceNode(nodeTag, resolved, children,
198 startEvent.getStartMark(), null, startEvent.getFlowStyle());
199 if (anchor != null) {
200 anchors.put(anchor, node);
201 }
202 int index = 0;
203 while (!parser.checkEvent(Event.ID.SequenceEnd)) {
204 children.add(composeNode(node));
205 index++;
206 }
207 Event endEvent = parser.getEvent();
208 node.setEndMark(endEvent.getEndMark());
209 return node;
210 }
211
212 private Node composeMappingNode(String anchor) {
213 MappingStartEvent startEvent = (MappingStartEvent) parser.getEvent();
214 String tag = startEvent.getTag();
215 Tag nodeTag;
216 boolean resolved = false;
217 if (tag == null || tag.equals("!")) {
218 nodeTag = resolver.resolve(NodeId.mapping, null, startEvent.getImplicit());
219 resolved = true;
220 } else {
221 nodeTag = new Tag(tag);
222 }
223
224 final List<NodeTuple> children = new ArrayList<NodeTuple>();
225 MappingNode node = new MappingNode(nodeTag, resolved, children, startEvent.getStartMark(),
226 null, startEvent.getFlowStyle());
227 if (anchor != null) {
228 anchors.put(anchor, node);
229 }
230 while (!parser.checkEvent(Event.ID.MappingEnd)) {
231 Node itemKey = composeNode(node);
232 if (itemKey.getTag().equals(Tag.MERGE)) {
233 node.setMerged(true);
234 } else if (itemKey.getTag().equals(Tag.VALUE)) {
235 itemKey.setTag(Tag.STR);
236 }
237 Node itemValue = composeNode(node);
238 children.add(new NodeTuple(itemKey, itemValue));
239 }
240 Event endEvent = parser.getEvent();
241 node.setEndMark(endEvent.getEndMark());
242 return node;
243 }
244 }