pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/core/util/QueryNodeOperation.java b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/core/util/QueryNodeOperation.java
new file mode 100644 (file)
index 0000000..e43ac73
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+++ b/lucene-java-3.5.0/lucene/contrib/queryparser/src/java/org/apache/lucene/queryParser/core/util/QueryNodeOperation.java
@@ -0,0 +1,94 @@
+package org.apache.lucene.queryParser.core.util;
+
+/**
+ * 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.QueryNodeError;
+import org.apache.lucene.queryParser.core.nodes.AndQueryNode;
+import org.apache.lucene.queryParser.core.nodes.QueryNode;
+
+/**
+ * Allow joining 2 QueryNode Trees, into one.
+ */
+public final class QueryNodeOperation {
+  private QueryNodeOperation() {
+    // Exists only to defeat instantiation.
+  }
+
+  private enum ANDOperation {
+    BOTH, Q1, Q2, NONE
+  }
+
+  /**
+   * perform a logical and of 2 QueryNode trees. if q1 and q2 are ANDQueryNode
+   * nodes it uses head Node from q1 and adds the children of q2 to q1 if q1 is
+   * a AND node and q2 is not, add q2 as a child of the head node of q1 if q2 is
+   * a AND node and q1 is not, add q1 as a child of the head node of q2 if q1
+   * and q2 are not ANDQueryNode nodes, create a AND node and make q1 and q2
+   * children of that node if q1 or q2 is null it returns the not null node if
+   * q1 = q2 = null it returns null
+   */
+  public final static QueryNode logicalAnd(QueryNode q1, QueryNode q2) {
+    if (q1 == null)
+      return q2;
+    if (q2 == null)
+      return q1;
+
+    ANDOperation op = null;
+    if (q1 instanceof AndQueryNode && q2 instanceof AndQueryNode)
+      op = ANDOperation.BOTH;
+    else if (q1 instanceof AndQueryNode)
+      op = ANDOperation.Q1;
+    else if (q1 instanceof AndQueryNode)
+      op = ANDOperation.Q2;
+    else
+      op = ANDOperation.NONE;
+
+    try {
+      QueryNode result = null;
+      switch (op) {
+      case NONE:
+        List<QueryNode> children = new ArrayList<QueryNode>();
+        children.add(q1.cloneTree());
+        children.add(q2.cloneTree());
+        result = new AndQueryNode(children);
+        return result;
+      case Q1:
+        result = q1.cloneTree();
+        result.add(q2.cloneTree());
+        return result;
+      case Q2:
+        result = q2.cloneTree();
+        result.add(q1.cloneTree());
+        return result;
+      case BOTH:
+        result = q1.cloneTree();
+        result.add(q2.cloneTree().getChildren());
+        return result;
+      }
+    } catch (CloneNotSupportedException e) {
+      throw new QueryNodeError(e);
+    }
+
+    return null;
+
+  }
+
+}