# NoChildOptimizationQueryNodeProcessor (Lucene 3.6.1 API)
Keywords: org.apache.lucene.queryParser.core.processors.NoChildOptimizationQueryNodeProcessor class

## org.apache.lucene.queryParser.core.processors
Class NoChildOptimizationQueryNodeProcessor

    java.lang.Object
      org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl
          org.apache.lucene.queryParser.core.processors.NoChildOptimizationQueryNodeProcessor

All Implemented Interfaces:
  QueryNodeProcessor

    public class NoChildOptimizationQueryNodeProcessor

extends QueryNodeProcessorImpl

A `NoChildOptimizationQueryNodeProcessor` removes every BooleanQueryNode, BoostQueryNode, TokenizedPhraseQueryNode or ModifierQueryNode that do not have a valid children.

Example: When the children of these nodes are removed for any reason then the nodes may become invalid.

Constructor Summary
`NoChildOptimizationQueryNodeProcessor()`

Method Summary
`protected QueryNode` `postProcessNode(QueryNode node)` This method is invoked for every node when walking up the tree.
`protected QueryNode` `preProcessNode(QueryNode node)` This method is invoked for every node when walking down the tree.
`protected List<QueryNode>` `setChildrenOrder(List<QueryNode> children)` This method is invoked for every node that has at least on child.

Methods inherited from class org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl
`getQueryConfigHandler, process, processChildren, setQueryConfigHandler`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### NoChildOptimizationQueryNodeProcessor

    public NoChildOptimizationQueryNodeProcessor()

Method Detail

### postProcessNode

    protected QueryNode postProcessNode(QueryNode node)
                                 throws QueryNodeException

  Description copied from class: `QueryNodeProcessorImpl`
  This method is invoked for every node when walking up the tree.

  Specified by:
    `postProcessNode` in class `QueryNodeProcessorImpl`
  Parameters:
    `node` - node the query node to be post-processed
  Returns:
    a query node
  Throws:
    `QueryNodeException` - if something goes wrong during the query node processing

### preProcessNode

    protected QueryNode preProcessNode(QueryNode node)
                                throws QueryNodeException

  Description copied from class: `QueryNodeProcessorImpl`
  This method is invoked for every node when walking down the tree.

  Specified by:
    `preProcessNode` in class `QueryNodeProcessorImpl`
  Parameters:
    `node` - the query node to be pre-processed
  Returns:
    a query node
  Throws:
    `QueryNodeException` - if something goes wrong during the query node processing

### setChildrenOrder

    protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
                                        throws QueryNodeException

  Description copied from class: `QueryNodeProcessorImpl`
  This method is invoked for every node that has at least on child. It's invoked right before `QueryNodeProcessorImpl.postProcessNode(QueryNode)` is invoked.

  Specified by:
    `setChildrenOrder` in class `QueryNodeProcessorImpl`
  Parameters:
    `children` - the list containing all current node's children
  Returns:
    a new list containing all children that should be set to the current node
  Throws:
    `QueryNodeException` - if something goes wrong during the query node processing