pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / facet / src / java / org / apache / lucene / facet / search / CategoryListIterator.java

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/search/CategoryListIterator.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/search/CategoryListIterator.java
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+package org.apache.lucene.facet.search;
+
+import java.io.IOException;
+
+/**
+ * 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 interface for iterating over a "category list", i.e., the list of
+ * categories per document.
+ * <p>
+ * <b>NOTE:</b>
+ * <ul>
+ * <li>This class operates as a key to a Map. Appropriate implementation of
+ * <code>hashCode()</code> and <code>equals()</code> must be provided.
+ * <li>{@link #init()} must be called before you consume any categories, or call
+ * {@link #skipTo(int)}.
+ * <li>{@link #skipTo(int)} must be called before any calls to
+ * {@link #nextCategory()}.
+ * <li>{@link #nextCategory()} returns values &lt; {@link Integer#MAX_VALUE}, so
+ * you can use it as a stop condition.
+ * </ul>
+ * 
+ * @lucene.experimental
+ */
+public interface CategoryListIterator {
+
+  /**
+   * Initializes the iterator. This method must be called before any calls to
+   * {@link #skipTo(int)}, and its return value indicates whether there are
+   * any relevant documents for this iterator. If it returns false, any call
+   * to {@link #skipTo(int)} will return false as well.<br>
+   * <b>NOTE:</b> calling this method twice may result in skipping over
+   * documents for some implementations. Also, calling it again after all
+   * documents were consumed may yield unexpected behavior.
+   */
+  public boolean init() throws IOException;
+
+  /**
+   * Skips forward to document docId. Returns true iff this document exists
+   * and has any categories. This method must be called before calling
+   * {@link #nextCategory()} for a particular document.<br>
+   * <b>NOTE:</b> Users should call this method with increasing docIds, and
+   * implementations can assume that this is the case.
+   */
+  public boolean skipTo(int docId) throws IOException;
+
+  /**
+   * Returns the next category for the current document that is set through
+   * {@link #skipTo(int)}, or a number higher than {@link Integer#MAX_VALUE}.
+   * No assumptions can be made on the order of the categories.
+   */
+  public long nextCategory() throws IOException;
+
+}