/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.lucene.queryparser.flexible.core.nodes;

import org.apache.lucene.queryparser.flexible.core.parser.EscapeQuerySyntax;

import java.util.List;
import java.util.Map;


A QueryNode is a interface implemented by all nodes on a QueryNode tree. /**
 * A {@link QueryNode} is a interface implemented by all nodes on a QueryNode
 * tree.
 */
public interface QueryNode {

  
convert to a query string understood by the query parser /** convert to a query string understood by the query parser */
  // TODO: this interface might be changed in the future
  public CharSequence toQueryString(EscapeQuerySyntax escapeSyntaxParser);

  
for printing /** for printing */
  @Override
  public String toString();

  
get Children nodes /** get Children nodes */
  public List<QueryNode> getChildren();

  
verify if a node is a Leaf node /** verify if a node is a Leaf node */
  public boolean isLeaf();

  
verify if a node contains a tag /** verify if a node contains a tag */
  public boolean containsTag(String tagName);
  
  
Returns object stored under that tag name
/**
   * Returns object stored under that tag name
   */
  public Object getTag(String tagName);
  
  public QueryNode getParent();

  
Recursive clone the QueryNode tree The tags are not copied to the new tree
when you call the cloneTree() method
Returns:
the cloned tree/**
   * Recursive clone the QueryNode tree The tags are not copied to the new tree
   * when you call the cloneTree() method
   * 
   * @return the cloned tree
   */
  public QueryNode cloneTree() throws CloneNotSupportedException;

  // Below are the methods that can change state of a QueryNode
  // Write Operations (not Thread Safe)

  // add a new child to a non Leaf node
  public void add(QueryNode child);

  public void add(List<QueryNode> children);

  // reset the children of a node
  public void set(List<QueryNode> children);

  
Associate the specified value with the specified tagName. If the tagName
already exists, the old value is replaced. The tagName and value cannot be
null. tagName will be converted to lowercase.
/**
   * Associate the specified value with the specified tagName. If the tagName
   * already exists, the old value is replaced. The tagName and value cannot be
   * null. tagName will be converted to lowercase.
   */
  public void setTag(String tagName, Object value);
  
  
Unset a tag. tagName will be converted to lowercase.
/**
   * Unset a tag. tagName will be converted to lowercase.
   */
  public void unsetTag(String tagName);
  
  
Returns a map containing all tags attached to this query node. 
Returns:
a map containing all tags attached to this query node/**
   * Returns a map containing all tags attached to this query node. 
   * 
   * @return a map containing all tags attached to this query node
   */
  public Map<String, Object> getTagMap();

  
Removes this query node from its parent.
/**
   * Removes this query node from its parent.
   */
  public void removeFromParent();


  
Remove a child node
Params:
childNode – Which child to remove/**
   * Remove a child node
   * @param childNode Which child to remove
   */
  public void removeChildren(QueryNode childNode);
}