+++ /dev/null
-package org.apache.lucene.queryParser.core.processors;
-
-/**
- * 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.
- */
-
-import java.util.ArrayList;
-import java.util.List;
-
-import org.apache.lucene.queryParser.core.QueryNodeException;
-import org.apache.lucene.queryParser.core.config.QueryConfigHandler;
-import org.apache.lucene.queryParser.core.nodes.QueryNode;
-
-/**
- * <p>
- * This is a default implementation for the {@link QueryNodeProcessor}
- * interface, it's an abstract class, so it should be extended by classes that
- * want to process a {@link QueryNode} tree.
- * </p>
- * <p>
- * This class process {@link QueryNode}s from left to right in the tree. While
- * it's walking down the tree, for every node,
- * {@link #preProcessNode(QueryNode)} is invoked. After a node's children are
- * processed, {@link #postProcessNode(QueryNode)} is invoked for that node.
- * {@link #setChildrenOrder(List)} is invoked before
- * {@link #postProcessNode(QueryNode)} only if the node has at least one child,
- * in {@link #setChildrenOrder(List)} the implementor might redefine the
- * children order or remove any children from the children list.
- * </p>
- * <p>
- * Here is an example about how it process the nodes:
- * </p>
- *
- * <pre>
- * a
- * / \
- * b e
- * / \
- * c d
- * </pre>
- *
- * Here is the order the methods would be invoked for the tree described above:
- *
- * <pre>
- * preProcessNode( a );
- * preProcessNode( b );
- * preProcessNode( c );
- * postProcessNode( c );
- * preProcessNode( d );
- * postProcessNode( d );
- * setChildrenOrder( bChildrenList );
- * postProcessNode( b );
- * preProcessNode( e );
- * postProcessNode( e );
- * setChildrenOrder( aChildrenList );
- * postProcessNode( a )
- * </pre>
- *
- * @see org.apache.lucene.queryParser.core.processors.QueryNodeProcessor
- */
-public abstract class QueryNodeProcessorImpl implements QueryNodeProcessor {
-
- private ArrayList<ChildrenList> childrenListPool = new ArrayList<ChildrenList>();
-
- private QueryConfigHandler queryConfig;
-
- public QueryNodeProcessorImpl() {
- // empty constructor
- }
-
- public QueryNodeProcessorImpl(QueryConfigHandler queryConfigHandler) {
- this.queryConfig = queryConfigHandler;
- }
-
- public QueryNode process(QueryNode queryTree) throws QueryNodeException {
- return processIteration(queryTree);
- }
-
- private QueryNode processIteration(QueryNode queryTree)
- throws QueryNodeException {
- queryTree = preProcessNode(queryTree);
-
- processChildren(queryTree);
-
- queryTree = postProcessNode(queryTree);
-
- return queryTree;
-
- }
-
- /**
- * This method is called every time a child is processed.
- *
- * @param queryTree
- * the query node child to be processed
- * @throws QueryNodeException
- * if something goes wrong during the query node processing
- */
- protected void processChildren(QueryNode queryTree) throws QueryNodeException {
-
- List<QueryNode> children = queryTree.getChildren();
- ChildrenList newChildren;
-
- if (children != null && children.size() > 0) {
-
- newChildren = allocateChildrenList();
-
- try {
-
- for (QueryNode child : children) {
- child = processIteration(child);
-
- if (child == null) {
- throw new NullPointerException();
-
- }
-
- newChildren.add(child);
-
- }
-
- List<QueryNode> orderedChildrenList = setChildrenOrder(newChildren);
-
- queryTree.set(orderedChildrenList);
-
- } finally {
- newChildren.beingUsed = false;
- }
-
- }
-
- }
-
- private ChildrenList allocateChildrenList() {
- ChildrenList list = null;
-
- for (ChildrenList auxList : this.childrenListPool) {
-
- if (!auxList.beingUsed) {
- list = auxList;
- list.clear();
-
- break;
-
- }
-
- }
-
- if (list == null) {
- list = new ChildrenList();
- this.childrenListPool.add(list);
-
- }
-
- list.beingUsed = true;
-
- return list;
-
- }
-
- /**
- * For reference about this method check:
- * {@link QueryNodeProcessor#setQueryConfigHandler(QueryConfigHandler)}.
- *
- * @param queryConfigHandler
- * the query configuration handler to be set.
- *
- * @see QueryNodeProcessor#getQueryConfigHandler()
- * @see QueryConfigHandler
- */
- public void setQueryConfigHandler(QueryConfigHandler queryConfigHandler) {
- this.queryConfig = queryConfigHandler;
- }
-
- /**
- * For reference about this method check:
- * {@link QueryNodeProcessor#getQueryConfigHandler()}.
- *
- * @return QueryConfigHandler the query configuration handler to be set.
- *
- * @see QueryNodeProcessor#setQueryConfigHandler(QueryConfigHandler)
- * @see QueryConfigHandler
- */
- public QueryConfigHandler getQueryConfigHandler() {
- return this.queryConfig;
- }
-
- /**
- * This method is invoked for every node when walking down the tree.
- *
- * @param node
- * the query node to be pre-processed
- *
- * @return a query node
- *
- * @throws QueryNodeException
- * if something goes wrong during the query node processing
- */
- abstract protected QueryNode preProcessNode(QueryNode node)
- throws QueryNodeException;
-
- /**
- * This method is invoked for every node when walking up the tree.
- *
- * @param node
- * node the query node to be post-processed
- *
- * @return a query node
- *
- * @throws QueryNodeException
- * if something goes wrong during the query node processing
- */
- abstract protected QueryNode postProcessNode(QueryNode node)
- throws QueryNodeException;
-
- /**
- * This method is invoked for every node that has at least on child. It's
- * invoked right before {@link #postProcessNode(QueryNode)} is invoked.
- *
- * @param children
- * the list containing all current node's children
- *
- * @return 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
- */
- abstract protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
- throws QueryNodeException;
-
- private static class ChildrenList extends ArrayList<QueryNode> {
-
- private static final long serialVersionUID = -2613518456949297135L;
-
- boolean beingUsed;
-
- }
-
-}
fnp / pylucene.git / blobdiff