pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/standard/processors/MultiFieldQueryNodeProcessor.java b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/standard/processors/MultiFieldQueryNodeProcessor.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/standard/processors/MultiFieldQueryNodeProcessor.java
@@ -0,0 +1,133 @@
+package org.apache.lucene.queryParser.standard.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.LinkedList;
+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.BooleanQueryNode;
+import org.apache.lucene.queryParser.core.nodes.FieldableNode;
+import org.apache.lucene.queryParser.core.nodes.GroupQueryNode;
+import org.apache.lucene.queryParser.core.nodes.QueryNode;
+import org.apache.lucene.queryParser.core.processors.QueryNodeProcessorImpl;
+import org.apache.lucene.queryParser.standard.config.StandardQueryConfigHandler.ConfigurationKeys;
+
+/**
+ * This processor is used to expand terms so the query looks for the same term
+ * in different fields. It also boosts a query based on its field. <br/>
+ * <br/>
+ * This processor looks for every {@link FieldableNode} contained in the query
+ * node tree. If a {@link FieldableNode} is found, it checks if there is a
+ * {@link ConfigurationKeys#MULTI_FIELDS} defined in the {@link QueryConfigHandler}. If
+ * there is, the {@link FieldableNode} is cloned N times and the clones are
+ * added to a {@link BooleanQueryNode} together with the original node. N is
+ * defined by the number of fields that it will be expanded to. The
+ * {@link BooleanQueryNode} is returned. <br/>
+ * 
+ * @see ConfigurationKeys#MULTI_FIELDS
+ */
+public class MultiFieldQueryNodeProcessor extends QueryNodeProcessorImpl {
+
+  private boolean processChildren = true;
+
+  public MultiFieldQueryNodeProcessor() {
+    // empty constructor
+  }
+
+  @Override
+  protected QueryNode postProcessNode(QueryNode node) throws QueryNodeException {
+
+    return node;
+
+  }
+
+  @Override
+  protected void processChildren(QueryNode queryTree) throws QueryNodeException {
+
+    if (this.processChildren) {
+      super.processChildren(queryTree);
+
+    } else {
+      this.processChildren = true;
+    }
+
+  }
+
+  @Override
+  protected QueryNode preProcessNode(QueryNode node) throws QueryNodeException {
+
+    if (node instanceof FieldableNode) {
+      this.processChildren = false;
+      FieldableNode fieldNode = (FieldableNode) node;
+
+      if (fieldNode.getField() == null) {
+        CharSequence[] fields = getQueryConfigHandler().get(ConfigurationKeys.MULTI_FIELDS);
+
+        if (fields == null) {
+          throw new IllegalArgumentException(
+              "StandardQueryConfigHandler.ConfigurationKeys.MULTI_FIELDS should be set on the QueryConfigHandler");
+        }
+
+        if (fields != null && fields.length > 0) {
+          fieldNode.setField(fields[0]);
+
+          if (fields.length == 1) {
+            return fieldNode;
+
+          } else {
+            LinkedList<QueryNode> children = new LinkedList<QueryNode>();
+            children.add(fieldNode);
+
+            for (int i = 1; i < fields.length; i++) {
+              try {
+                fieldNode = (FieldableNode) fieldNode.cloneTree();
+                fieldNode.setField(fields[i]);
+
+                children.add(fieldNode);
+
+              } catch (CloneNotSupportedException e) {
+                // should never happen
+              }
+
+            }
+
+            return new GroupQueryNode(new BooleanQueryNode(children));
+
+          }
+
+        }
+
+      }
+
+    }
+
+    return node;
+
+  }
+
+  @Override
+  protected List<QueryNode> setChildrenOrder(List<QueryNode> children)
+      throws QueryNodeException {
+
+    return children;
+
+  }
+
+}