Added search modifiers that were moved from Asterix.

git-svn-id: https://hyracks.googlecode.com/svn/branches/hyracks_lsm_tree@2496 123451ca-8445-de46-9d55-352943316053
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/ListEditDistanceSearchModifier.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/ListEditDistanceSearchModifier.java
new file mode 100644
index 0000000..8ae22a5
--- /dev/null
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/ListEditDistanceSearchModifier.java
@@ -0,0 +1,55 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed 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 from
+ * 
+ *     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.
+ */
+
+package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search;
+
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexSearchModifier;
+
+public class ListEditDistanceSearchModifier implements IInvertedIndexSearchModifier {
+
+    private int edThresh;
+
+    public ListEditDistanceSearchModifier(int edThresh) {
+        this.edThresh = edThresh;
+    }
+
+    public int getEdThresh() {
+        return edThresh;
+    }
+
+    public void setEdThresh(int edThresh) {
+        this.edThresh = edThresh;
+    }
+
+    @Override
+    public int getOccurrenceThreshold(int numQueryTokens) {
+        return numQueryTokens - edThresh;
+    }
+
+    @Override
+    public int getNumPrefixLists(int occurrenceThreshold, int numInvLists) {
+        return numInvLists - occurrenceThreshold + 1;
+    }
+
+    @Override
+    public short getNumTokensLowerBound(short numQueryTokens) {
+        return (short) (numQueryTokens - edThresh);
+    }
+
+    @Override
+    public short getNumTokensUpperBound(short numQueryTokens) {
+        return (short) (numQueryTokens + edThresh);
+    }
+}
diff --git a/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/ListEditDistanceSearchModifierFactory.java b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/ListEditDistanceSearchModifierFactory.java
new file mode 100644
index 0000000..d8f57b1
--- /dev/null
+++ b/hyracks-storage-am-lsm-invertedindex/src/main/java/edu/uci/ics/hyracks/storage/am/lsm/invertedindex/search/ListEditDistanceSearchModifierFactory.java
@@ -0,0 +1,35 @@
+/*
+ * Copyright 2009-2010 by The Regents of the University of California
+ * Licensed 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 from
+ * 
+ *     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.
+ */
+
+package edu.uci.ics.hyracks.storage.am.lsm.invertedindex.search;
+
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexSearchModifier;
+import edu.uci.ics.hyracks.storage.am.lsm.invertedindex.api.IInvertedIndexSearchModifierFactory;
+
+public class ListEditDistanceSearchModifierFactory implements IInvertedIndexSearchModifierFactory {
+
+    private static final long serialVersionUID = 1L;
+
+    private final int edThresh;
+
+    public ListEditDistanceSearchModifierFactory(int edThresh) {
+        this.edThresh = edThresh;
+    }
+
+    @Override
+    public IInvertedIndexSearchModifier createSearchModifier() {
+        return new ListEditDistanceSearchModifier(edThresh);
+    }
+}