pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / queryparser / src / java / org / apache / lucene / queryParser / core / processors / NoChildOptimizationQueryNodeProcessor.java

diff --git a/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/core/processors/NoChildOptimizationQueryNodeProcessor.java b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/core/processors/NoChildOptimizationQueryNodeProcessor.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/core/processors/NoChildOptimizationQueryNodeProcessor.java
@@ -0,0 +1,93 @@
+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.List;
+
+import org.apache.lucene.queryParser.core.QueryNodeException;
+import org.apache.lucene.queryParser.core.nodes.BooleanQueryNode;
+import org.apache.lucene.queryParser.core.nodes.BoostQueryNode;
+import org.apache.lucene.queryParser.core.nodes.DeletedQueryNode;
+import org.apache.lucene.queryParser.core.nodes.MatchNoDocsQueryNode;
+import org.apache.lucene.queryParser.core.nodes.ModifierQueryNode;
+import org.apache.lucene.queryParser.core.nodes.QueryNode;
+import org.apache.lucene.queryParser.core.nodes.TokenizedPhraseQueryNode;
+
+/**
+ * <p>
+ * A {@link NoChildOptimizationQueryNodeProcessor} removes every
+ * BooleanQueryNode, BoostQueryNode, TokenizedPhraseQueryNode or
+ * ModifierQueryNode that do not have a valid children.
+ * </p>
+ * <p>
+ * Example: When the children of these nodes are removed for any reason then the
+ * nodes may become invalid.
+ * </p>
+ */
+public class NoChildOptimizationQueryNodeProcessor extends
+    QueryNodeProcessorImpl {
+
+  public NoChildOptimizationQueryNodeProcessor() {
+    // empty constructor
+  }
+
+  @Override
+  protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
+
+    if (node instanceof BooleanQueryNode || node instanceof BoostQueryNode
+        || node instanceof TokenizedPhraseQueryNode
+        || node instanceof ModifierQueryNode) {
+
+      List<QueryNode> children = node.getChildren();
+
+      if (children != null && children.size() > 0) {
+
+        for (QueryNode child : children) {
+
+          if (!(child instanceof DeletedQueryNode)) {
+            return node;
+          }
+
+        }
+
+      }
+
+      return new MatchNoDocsQueryNode();
+
+    }
+
+    return node;
+
+  }
+
+  @Override
+  protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
+
+    return node;
+
+  }
+
+  @Override
+  protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
+      throws QueryNodeException {
+
+    return children;
+
+  }
+
+}