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.
/**
 * 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 Composer, and later transformed into application specific Java classes by the classes from the constructor package. 
/**
 * Base class for all nodes.
 * <p>
 * The nodes form the node-graph described in the <a
 * href="http://yaml.org/spec/1.1/">YAML Specification</a>.
 * </p>
 * <p>
 * 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.
 * </p>
 */
public abstract class Node {
    private Tag tag;
    private Mark startMark;
    protected Mark endMark;
    private Class<? extends Object> type;
    private boolean twoStepsConstruction;
    private String anchor;

    
true when the tag is assigned by the resolver
/**
     * 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.
Returns:
Tag of this node./**
     * Tag of this node.
     * <p>
     * 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 Also:
class variable 'id' in PyYAML
Returns:
scalar, sequence, mapping/**
     * 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;
    }

    
Node is only equal to itself
/**
     * Node is only equal to itself
     */
    @Override
    public final boolean equals(Object obj) {
        return super.equals(obj);
    }

    public Class<? extends Object> getType() {
        return type;
    }

    public void setType(Class<? extends Object> 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 Composer, used during the construction process. 

Only relevant during loading.

Returns:
true if the node is self referenced./**
     * Indicates if this node must be constructed in two steps.
     * <p>
     * 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.
     * </p>
     * <p>
     * Set by {@link org.yaml.snakeyaml.composer.Composer}, used during the
     * construction process.
     * </p>
     * <p>
     * Only relevant during loading.
     * </p>
     * 
     * @return <code>true</code> 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() && resolved && !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 Resolver. 
Returns:
true if the tag of this node was resolved
Deprecated:
Since v1.22.  Absent in immediately prior versions, but present previously.  Restored deprecated for backwards compatibility./**
     * Indicates if the tag was added by
     * {@link org.yaml.snakeyaml.resolver.Resolver}.
     * 
     * @return true if the tag of this node was resolved
     * 
     * @deprecated Since v1.22.  Absent in immediately prior versions, but present previously.  Restored deprecated for backwards compatibility.
     */
    @Deprecated
    public boolean isResolved() {
        return resolved;
    }

    public String getAnchor() {
        return anchor;
    }

    public void setAnchor(String anchor) {
        this.anchor = anchor;
    }
}