pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / facet / src / java / org / apache / lucene / facet / index / streaming / CategoryAttributesStream.java

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/index/streaming/CategoryAttributesStream.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/index/streaming/CategoryAttributesStream.java
new file mode 100644 (file)
index 0000000..a869219
--- /dev/null
+++ b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/index/streaming/CategoryAttributesStream.java
@@ -0,0 +1,81 @@
+package org.apache.lucene.facet.index.streaming;
+
+import java.io.IOException;
+import java.util.Iterator;
+
+import org.apache.lucene.analysis.TokenStream;
+
+import org.apache.lucene.facet.index.attributes.CategoryAttribute;
+
+/**
+ * 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.
+ */
+
+/**
+ * An attribute stream built from an {@link Iterable} of
+ * {@link CategoryAttribute}. This stream should then be passed through several
+ * filters (see {@link CategoryParentsStream}, {@link CategoryListTokenizer} and
+ * {@link CategoryTokenizer}) until a token stream is produced that can be
+ * indexed by Lucene.
+ * <P>
+ * A CategoryAttributesStream object can be reused for producing more than one
+ * stream. To do that, the user should cause the underlying
+ * Iterable<CategoryAttribute> object to return a new set of categories, and
+ * then call {@link #reset()} to allow this stream to be used again.
+ * 
+ * @lucene.experimental
+ */
+public class CategoryAttributesStream extends TokenStream {
+
+  protected CategoryAttribute categoryAttribute;
+
+  private Iterable<CategoryAttribute> iterable;
+  private Iterator<CategoryAttribute> iterator;
+
+  /**
+   * Constructor
+   * 
+   * @param iterable
+   *            {@link Iterable} of {@link CategoryAttribute}, from which
+   *            categories are taken.
+   */
+  public CategoryAttributesStream(Iterable<CategoryAttribute> iterable) {
+    this.iterable = iterable;
+    this.iterator = null;
+    this.categoryAttribute = this.addAttribute(CategoryAttribute.class);
+  }
+
+  @Override
+  public final boolean incrementToken() throws IOException {
+    if (iterator == null) {
+      if (iterable == null) {
+        return false;
+      }
+      iterator = iterable.iterator();
+    }
+    if (iterator.hasNext()) {
+      categoryAttribute.set(iterator.next());
+      return true;
+    }
+    return false;
+  }
+
+  @Override
+  public void reset() {
+    this.iterator = null;
+  }
+
+}