/*
 * Copyright 2016-present Open Networking Laboratory
 *
 * 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.onosproject.store.service;

import java.util.Iterator;

import javax.annotation.concurrent.NotThreadSafe;

/**
 * A {@code DocumentTree} node.
 *
 * @param <V> value type
 */
@NotThreadSafe
public interface DocumentTreeNode<V> {

    /**
     * Returns the path to this node in a {@code DocumentTree}.
     *
     * @return absolute path
     */
    DocumentPath path();

    /**
     * Returns the value of this node.
     *
     * @return node value (and version)
     */
    Versioned<V> value();

    /**
     * Returns the children of this node.
     *
     * @return iterator for this node's children
     */
    Iterator<DocumentTreeNode<V>> children();

    /**
     * Returns the child node of this node with the specified relative path name.
     *
     * @param relativePath relative path name for the child node.
     * @return child node; this method returns {@code null} if no such child exists
     */
    DocumentTreeNode<V> child(String relativePath);

    /**
     * Returns if this node has one or more children.
     * @return {@code true} if yes, {@code false} otherwise
     */
    default boolean hasChildren() {
        return children().hasNext();
    }
}