org.yaml.snakeyaml.nodes.Node Maven / Gradle / Ivy
/**
* Copyright (c) 2008, 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 org.yaml.snakeyaml.nodes;
import org.yaml.snakeyaml.error.Mark;
/**
* Base class for all nodes.
*
* The nodes form the node-graph described in the YAML Specification.
*
*
* While loading, the node graph is usually created by the
* {@link org.yaml.snakeyaml.composer.Composer}, and later transformed into
* application specific Java classes by the classes from the
* {@link org.yaml.snakeyaml.constructor} package.
*
*/
public abstract class Node {
private Tag tag;
private Mark startMark;
protected Mark endMark;
private Class type;
private boolean twoStepsConstruction;
/**
* true when the tag is assigned by the resolver
*/
protected boolean resolved;
protected Boolean useClassConstructor;
public Node(Tag tag, Mark startMark, Mark endMark) {
setTag(tag);
this.startMark = startMark;
this.endMark = endMark;
this.type = Object.class;
this.twoStepsConstruction = false;
this.resolved = true;
this.useClassConstructor = null;
}
/**
* Tag of this node.
*
* Every node has a tag assigned. The tag is either local or global.
*
* @return Tag of this node.
*/
public Tag getTag() {
return this.tag;
}
public Mark getEndMark() {
return endMark;
}
/**
* For error reporting.
*
* @see "class variable 'id' in PyYAML"
* @return scalar, sequence, mapping
*/
public abstract NodeId getNodeId();
public Mark getStartMark() {
return startMark;
}
public void setTag(Tag tag) {
if (tag == null) {
throw new NullPointerException("tag in a Node is required.");
}
this.tag = tag;
}
/**
* Two Nodes are never equal.
*/
@Override
public final boolean equals(Object obj) {
return super.equals(obj);
}
public Class getType() {
return type;
}
public void setType(Class type) {
if (!type.isAssignableFrom(this.type)) {
this.type = type;
}
}
public void setTwoStepsConstruction(boolean twoStepsConstruction) {
this.twoStepsConstruction = twoStepsConstruction;
}
/**
* Indicates if this node must be constructed in two steps.
*
* Two-step construction is required whenever a node is a child (direct or
* indirect) of it self. That is, if a recursive structure is build using
* anchors and aliases.
*
*
* Set by {@link org.yaml.snakeyaml.composer.Composer}, used during the
* construction process.
*
*
* Only relevant during loading.
*
*
* @return true if the node is self referenced.
*/
public boolean isTwoStepsConstruction() {
return twoStepsConstruction;
}
@Override
public final int hashCode() {
return super.hashCode();
}
public boolean useClassConstructor() {
if (useClassConstructor == null) {
if (!tag.isSecondary() && isResolved() && !Object.class.equals(type)
&& !tag.equals(Tag.NULL)) {
return true;
} else if (tag.isCompatible(getType())) {
// the tag is compatible with the runtime class
// the tag will be ignored
return true;
} else {
return false;
}
}
return useClassConstructor.booleanValue();
}
public void setUseClassConstructor(Boolean useClassConstructor) {
this.useClassConstructor = useClassConstructor;
}
/**
* Indicates if the tag was added by
* {@link org.yaml.snakeyaml.resolver.Resolver}.
*
* @return true if the tag of this node was resolved
*/
public boolean isResolved() {
return resolved;
}
}