pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / facet / src / java / org / apache / lucene / facet / util / PartitionsUtils.java

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/util/PartitionsUtils.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/util/PartitionsUtils.java
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+package org.apache.lucene.facet.util;
+
+import org.apache.lucene.facet.index.params.CategoryListParams;
+import org.apache.lucene.facet.index.params.FacetIndexingParams;
+import org.apache.lucene.facet.search.params.FacetSearchParams;
+import org.apache.lucene.facet.taxonomy.TaxonomyReader;
+
+/**
+ * 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.
+ */
+
+/**
+ * Utilities for partitions - sizes and such
+ * 
+ * @lucene.experimental
+ */
+public final class PartitionsUtils {
+
+  /**
+   * Get the offset for a given partition.  That is, what is the minimum number an
+   * ordinal could be for a particular partition. 
+   */
+  public final static int partitionOffset (  FacetIndexingParams iParams, 
+                        int partitionNumber, 
+                        final TaxonomyReader taxonomyReader) {
+    return partitionNumber * partitionSize(iParams, taxonomyReader);
+  }
+
+  /**
+   * @see #partitionOffset(FacetIndexingParams, int, TaxonomyReader)
+   */
+  public final static int partitionOffset (  FacetSearchParams sParams, 
+                        int partitionNumber, 
+                        final TaxonomyReader taxonomyReader) {
+    return partitionOffset(sParams.getFacetIndexingParams(), partitionNumber, taxonomyReader);
+  }
+
+  /**
+   * Get the partition size in this parameter, or return the size of the taxonomy, which
+   * is smaller.  (Guarantees usage of as little memory as possible at search time).
+   */
+  public final static int partitionSize(FacetIndexingParams indexingParams, final TaxonomyReader taxonomyReader) {
+    return Math.min(indexingParams.getPartitionSize(), taxonomyReader.getSize());
+  }
+
+  /**
+   * @see #partitionSize(FacetIndexingParams, TaxonomyReader)
+   */
+  public final static int partitionSize(FacetSearchParams sParams, final TaxonomyReader taxonomyReader) {
+    return partitionSize(sParams.getFacetIndexingParams(), taxonomyReader);
+  }
+
+  /**
+   * Partition number of an ordinal.
+   * <p>
+   * This allows to locate the partition containing a certain (facet) ordinal.
+   * @see FacetIndexingParams#getPartitionSize()      
+   */
+  public final static int partitionNumber(FacetIndexingParams iParams, int ordinal) {
+    return ordinal / iParams.getPartitionSize();
+  }
+
+  /**
+   * @see #partitionNumber(FacetIndexingParams, int)
+   */
+  public final static int partitionNumber(FacetSearchParams sParams, int ordinal) {
+    return partitionNumber(sParams.getFacetIndexingParams(), ordinal);
+  }
+
+  /**
+   * Partition name by category ordinal
+   */
+  public final static String partitionNameByOrdinal(  FacetIndexingParams iParams, 
+                            CategoryListParams clParams, 
+                            int ordinal) {
+    int partition = partitionNumber(iParams, ordinal); 
+    return partitionName(clParams, partition);
+  }
+
+  /** 
+   * Partition name by its number
+   */
+  public final static String partitionName(CategoryListParams clParams, int partition) {
+    String term = clParams.getTerm().text();
+    if (partition == 0) {
+      return term; // for backwards compatibility we do not add a partition number in this case
+    }
+    return term + partition;
+  }
+
+}