pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / src / java / org / apache / lucene / search / FilteredDocIdSetIterator.java

diff --git a/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/FilteredDocIdSetIterator.java b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/FilteredDocIdSetIterator.java
new file mode 100644 (file)
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+++ b/lucene-java-3.5.0/lucene/src/java/org/apache/lucene/search/FilteredDocIdSetIterator.java
@@ -0,0 +1,85 @@
+package org.apache.lucene.search;
+
+/**
+ * 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.
+ */
+
+import java.io.IOException;
+
+/**
+ * Abstract decorator class of a DocIdSetIterator
+ * implementation that provides on-demand filter/validation
+ * mechanism on an underlying DocIdSetIterator.  See {@link
+ * FilteredDocIdSet}.
+ */
+public abstract class FilteredDocIdSetIterator extends DocIdSetIterator {
+  protected DocIdSetIterator _innerIter;
+  private int doc;
+       
+  /**
+   * Constructor.
+   * @param innerIter Underlying DocIdSetIterator.
+   */
+  public FilteredDocIdSetIterator(DocIdSetIterator innerIter) {
+    if (innerIter == null) {
+      throw new IllegalArgumentException("null iterator");
+    }
+    _innerIter = innerIter;
+    doc = -1;
+  }
+       
+  /**
+   * Validation method to determine whether a docid should be in the result set.
+   * @param doc docid to be tested
+   * @return true if input docid should be in the result set, false otherwise.
+   * @see #FilteredDocIdSetIterator(DocIdSetIterator)
+   */
+  abstract protected boolean match(int doc) throws IOException;
+       
+  @Override
+  public int docID() {
+    return doc;
+  }
+  
+  @Override
+  public int nextDoc() throws IOException {
+    while ((doc = _innerIter.nextDoc()) != NO_MORE_DOCS) {
+      if (match(doc)) {
+        return doc;
+      }
+    }
+    return doc;
+  }
+  
+  @Override
+  public int advance(int target) throws IOException {
+    doc = _innerIter.advance(target);
+    if (doc != NO_MORE_DOCS) {
+      if (match(doc)) {
+        return doc;
+      } else {
+        while ((doc = _innerIter.nextDoc()) != NO_MORE_DOCS) {
+          if (match(doc)) {
+            return doc;
+          }
+        }
+        return doc;
+      }
+    }
+    return doc;
+  }
+  
+}