pylucene 3.5.0-3

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

diff --git a/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/util/MultiCategoryListIterator.java b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/util/MultiCategoryListIterator.java
new file mode 100644 (file)
index 0000000..3a6e509
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+++ b/lucene-java-3.5.0/lucene/contrib/facet/src/java/org/apache/lucene/facet/util/MultiCategoryListIterator.java
@@ -0,0 +1,83 @@
+package org.apache.lucene.facet.util;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.lucene.facet.search.CategoryListIterator;
+
+/**
+ * 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.
+ */
+
+/**
+ * Iterates over multiple {@link CategoryListIterator}s, consuming the provided
+ * iterators in order.
+ * 
+ * @lucene.experimental
+ */
+public class MultiCategoryListIterator implements CategoryListIterator {
+
+  private final CategoryListIterator[] iterators;
+  private final List<CategoryListIterator> validIterators;
+  private final List<CategoryListIterator> perDocValidIterators;
+
+  /** Receives the iterators to iterate on */
+  public MultiCategoryListIterator(CategoryListIterator... iterators) {
+    this.iterators = iterators;
+    this.validIterators = new ArrayList<CategoryListIterator>();
+    this.perDocValidIterators = new ArrayList<CategoryListIterator>();
+  }
+
+  /** Fails if all given iterators fail to init */
+  public boolean init() throws IOException {
+    for (CategoryListIterator cli : iterators) {
+      if (cli.init()) {
+        validIterators.add(cli);
+      }
+    }
+    return !validIterators.isEmpty();
+  }
+
+  /**
+   * Return a value larger than {@link Integer#MAX_VALUE} only if all
+   * iterators are exhausted
+   */
+  public long nextCategory() throws IOException {
+    while (!perDocValidIterators.isEmpty()) {
+      long value = perDocValidIterators.get(0).nextCategory();
+      if (value <= Integer.MAX_VALUE) {
+        return value;
+      }
+      perDocValidIterators.remove(0);
+    }
+    return 0x100000000L;
+  }
+
+  /**
+   * Fails only if skipTo on all the provided iterators returned {@code false}
+   */
+  public boolean skipTo(int docId) throws IOException {
+    perDocValidIterators.clear();
+    for (CategoryListIterator cli : validIterators) {
+      if (cli.skipTo(docId)) {
+        perDocValidIterators.add(cli);
+      }
+    }
+    return !perDocValidIterators.isEmpty();
+  }
+
+}