--- /dev/null
+package org.apache.lucene.facet.enhancements.association;
+
+import java.util.HashSet;
+import java.util.Set;
+
+import org.apache.lucene.analysis.TokenStream;
+
+import org.apache.lucene.facet.enhancements.CategoryEnhancement;
+import org.apache.lucene.facet.enhancements.params.EnhancementsIndexingParams;
+import org.apache.lucene.facet.index.attributes.CategoryAttribute;
+import org.apache.lucene.facet.index.attributes.CategoryProperty;
+import org.apache.lucene.facet.index.streaming.CategoryListTokenizer;
+import org.apache.lucene.facet.taxonomy.TaxonomyWriter;
+import org.apache.lucene.util.Vint8;
+import org.apache.lucene.util.Vint8.Position;
+
+/**
+ * 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.
+ */
+
+/**
+ * A {@link CategoryEnhancement} for adding associations data to the index
+ * (categories with {@link AssociationProperty}s).
+ *
+ * @lucene.experimental
+ */
+public class AssociationEnhancement implements CategoryEnhancement {
+
+ static final String CATEGORY_LIST_TERM_TEXT = "CATEGORY_ASSOCIATION_LIST";
+
+ /** Property Classes which extend AssociationProperty */
+ private static final HashSet<Class<? extends CategoryProperty>> ASSOCIATION_PROPERTY_CLASSES;
+
+ /** Property Classes which do not extend AssociationProperty */
+ private static final HashSet<Class<? extends CategoryProperty>> NON_ASSOCIATION_PROPERTY_CLASSES;
+
+ static {
+ ASSOCIATION_PROPERTY_CLASSES = new HashSet<Class<? extends CategoryProperty>>();
+ NON_ASSOCIATION_PROPERTY_CLASSES = new HashSet<Class<? extends CategoryProperty>>();
+ }
+
+ /**
+ * For a given class which extends a CategoryProperty, answers whether it is
+ * an instance of AssociationProperty (AP) or not. <br>
+ * This method is a cheaper replacement for a call to
+ * <code>instanceof</code>. It has two HashSets - one for classes which are
+ * an extension to AP and one for the classes which are not. Whenever a
+ * property class is introduced:
+ * <ul>
+ * <li>if it is known as a property class extending AP (contained in the
+ * validHashSet)- returns true</li>
+ * <li>if it is known as a property class NOT extending AP - returns false</li>
+ * <li>
+ * If it was not matched against both sets, it calls 'instanceof' to find
+ * out if it extends AP, puts it in the matching Set and returning true or
+ * false accordingly</li>
+ *</ul>
+ *
+ * NOTE: 'instanceof' is only called once per a Class (not instance) of a
+ * property. And as there are few properties (currently 4 concrete
+ * implementations) the two sets would be rather small
+ */
+ public static boolean isAssociationProperty(Class<? extends CategoryProperty> clazz) {
+ if (ASSOCIATION_PROPERTY_CLASSES.contains(clazz)) {
+ return true;
+ }
+
+ if (NON_ASSOCIATION_PROPERTY_CLASSES.contains(clazz)) {
+ return false;
+ }
+
+ if (AssociationProperty.class.isAssignableFrom(clazz)) {
+ ASSOCIATION_PROPERTY_CLASSES.add(clazz);
+ return true;
+ }
+
+ NON_ASSOCIATION_PROPERTY_CLASSES.add(clazz);
+ return false;
+ }
+
+ public boolean generatesCategoryList() {
+ return true;
+ }
+
+ public String getCategoryListTermText() {
+ return CATEGORY_LIST_TERM_TEXT;
+ }
+
+ public CategoryListTokenizer getCategoryListTokenizer(
+ TokenStream tokenizer, EnhancementsIndexingParams indexingParams,
+ TaxonomyWriter taxonomyWriter) {
+ return new AssociationListTokenizer(tokenizer, indexingParams, this);
+ }
+
+ public byte[] getCategoryTokenBytes(CategoryAttribute categoryAttribute) {
+
+ AssociationProperty property = getAssociationProperty(categoryAttribute);
+
+ if (property == null) {
+ return null;
+ }
+
+ int association = property.getAssociation();
+ int bytesNeeded = Vint8.bytesNeeded(association);
+ byte[] buffer = new byte[bytesNeeded];
+ Vint8.encode(association, buffer, 0);
+ return buffer;
+ }
+
+ public static AssociationProperty getAssociationProperty(
+ CategoryAttribute categoryAttribute) {
+ AssociationProperty property = null;
+ Set<Class<? extends CategoryProperty>> propertyClasses = categoryAttribute
+ .getPropertyClasses();
+ if (propertyClasses == null) {
+ return null;
+ }
+ for (Class<? extends CategoryProperty> clazz : propertyClasses) {
+ if (isAssociationProperty(clazz)) {
+ property = (AssociationProperty) categoryAttribute
+ .getProperty(clazz);
+ break;
+ }
+ }
+ return property;
+ }
+
+ public Object extractCategoryTokenData(byte[] buffer, int offset, int length) {
+ if (length == 0) {
+ return null;
+ }
+ Integer i = Integer.valueOf(Vint8.decode(buffer, new Position(offset)));
+ return i;
+ }
+
+ public Class<? extends CategoryProperty> getRetainableProperty() {
+ return null;
+ }
+
+}
fnp / pylucene.git / blobdiff