com.hazelcast.org.snakeyaml.engine.v2.representer.BaseRepresenter Maven / Gradle / Ivy
/**
* Copyright (c) 2018, http://www.snakeyaml.org
*
* 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 com.hazelcast.org.snakeyaml.engine.v2.representer;
import com.hazelcast.org.snakeyaml.engine.v2.api.RepresentToNode;
import com.hazelcast.org.snakeyaml.engine.v2.common.FlowStyle;
import com.hazelcast.org.snakeyaml.engine.v2.common.ScalarStyle;
import com.hazelcast.org.snakeyaml.engine.v2.exceptions.YamlEngineException;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.AnchorNode;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.MappingNode;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.Node;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.NodeTuple;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.ScalarNode;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.SequenceNode;
import com.hazelcast.org.snakeyaml.engine.v2.nodes.Tag;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
/**
* Represent basic YAML structures: scalar, sequence, mapping
*/
public abstract class BaseRepresenter {
/**
* Keep representers which must match the class exactly
*/
protected final Map, RepresentToNode> representers = new HashMap();
/**
* in Java 'null' is not a type. So we have to keep the null representer
* separately otherwise it will coincide with the default representer which
* is stored with the key null.
*/
protected RepresentToNode nullRepresenter;
// the order is important (map can be also a sequence of key-values)
/**
* Keep representers which match a parent of the class to be represented
*/
protected final Map, RepresentToNode> parentClassRepresenters = new LinkedHashMap();
protected ScalarStyle defaultScalarStyle = ScalarStyle.PLAIN;
protected FlowStyle defaultFlowStyle = FlowStyle.AUTO;
protected final Map representedObjects = new IdentityHashMap() {
@Override
public Node put(Object key, Node value) {
return super.put(key, new AnchorNode(value));
}
};
protected Object objectToRepresent;
/**
* Represent the provided Java instance to a Node
*
* @param data - Java instance to be represented
* @return The Node to be serialized
*/
public Node represent(Object data) {
Node node = representData(data);
representedObjects.clear();
objectToRepresent = null;
return node;
}
/**
* Find the representer which is suitable to represent the internal structure of the provided instance to
* a Node
*
* @param data - the data to be serialized
* @return RepresentToNode to call to create a Node
*/
protected Optional findRepresenterFor(Object data) {
Class clazz = data.getClass();
// check the same class
if (representers.containsKey(clazz)) {
return Optional.of(representers.get(clazz));
} else {
// check the parents
for (Map.Entry, RepresentToNode> parentRepresenterEntry : parentClassRepresenters.entrySet()) {
if (parentRepresenterEntry.getKey().isInstance(data)) {
return Optional.of(parentRepresenterEntry.getValue());
}
}
return Optional.empty();
}
}
protected final Node representData(Object data) {
objectToRepresent = data;
// check for identity
if (representedObjects.containsKey(objectToRepresent)) {
return representedObjects.get(objectToRepresent);
}
// check for null first
if (data == null) {
return nullRepresenter.representData(null);
}
RepresentToNode representer = findRepresenterFor(data)
.orElseThrow(() -> new YamlEngineException("Representer is not defined for " + data.getClass()));
return representer.representData(data);
}
protected Node representScalar(Tag tag, String value, ScalarStyle style) {
if (style == ScalarStyle.PLAIN) {
style = this.defaultScalarStyle;
}
return new ScalarNode(tag, value, style);
}
protected Node representScalar(Tag tag, String value) {
return representScalar(tag, value, ScalarStyle.PLAIN);
}
protected Node representSequence(Tag tag, Iterable sequence, FlowStyle flowStyle) {
int size = 10;// default for ArrayList
if (sequence instanceof List) {
size = ((List) sequence).size();
}
List value = new ArrayList<>(size);
SequenceNode node = new SequenceNode(tag, value, flowStyle);
representedObjects.put(objectToRepresent, node);
FlowStyle bestStyle = FlowStyle.FLOW;
for (Object item : sequence) {
Node nodeItem = representData(item);
if (!(nodeItem instanceof ScalarNode && ((ScalarNode) nodeItem).isPlain())) {
bestStyle = FlowStyle.BLOCK;
}
value.add(nodeItem);
}
if (flowStyle == FlowStyle.AUTO) {
if (defaultFlowStyle != FlowStyle.AUTO) {
node.setFlowStyle(defaultFlowStyle);
} else {
node.setFlowStyle(bestStyle);
}
}
return node;
}
protected Node representMapping(Tag tag, Map mapping, FlowStyle flowStyle) {
List value = new ArrayList<>(mapping.size());
MappingNode node = new MappingNode(tag, value, flowStyle);
representedObjects.put(objectToRepresent, node);
FlowStyle bestStyle = FlowStyle.FLOW;
for (Map.Entry entry : mapping.entrySet()) {
Node nodeKey = representData(entry.getKey());
Node nodeValue = representData(entry.getValue());
if (!(nodeKey instanceof ScalarNode && ((ScalarNode) nodeKey).isPlain())) {
bestStyle = FlowStyle.BLOCK;
}
if (!(nodeValue instanceof ScalarNode && ((ScalarNode) nodeValue).isPlain())) {
bestStyle = FlowStyle.BLOCK;
}
value.add(new NodeTuple(nodeKey, nodeValue));
}
if (flowStyle == FlowStyle.AUTO) {
if (defaultFlowStyle != FlowStyle.AUTO) {
node.setFlowStyle(defaultFlowStyle);
} else {
node.setFlowStyle(bestStyle);
}
}
return node;
}
}