pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / analyzers / common / src / java / org / apache / lucene / analysis / position / PositionFilter.java

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/position/PositionFilter.java b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/position/PositionFilter.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/common/src/java/org/apache/lucene/analysis/position/PositionFilter.java
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+package org.apache.lucene.analysis.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.
+ */
+
+import java.io.IOException;
+
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
+
+/** Set the positionIncrement of all tokens to the "positionIncrement",
+ * except the first return token which retains its original positionIncrement value.
+ * The default positionIncrement value is zero.
+ */
+public final class PositionFilter extends TokenFilter {
+
+  /** Position increment to assign to all but the first token - default = 0 */
+  private int positionIncrement = 0;
+  
+  /** The first token must have non-zero positionIncrement **/
+  private boolean firstTokenPositioned = false;
+  
+  private PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
+
+  /**
+   * Constructs a PositionFilter that assigns a position increment of zero to
+   * all but the first token from the given input stream.
+   * 
+   * @param input the input stream
+   */
+  public PositionFilter(final TokenStream input) {
+    super(input);
+  }
+
+  /**
+   * Constructs a PositionFilter that assigns the given position increment to
+   * all but the first token from the given input stream.
+   * 
+   * @param input the input stream
+   * @param positionIncrement position increment to assign to all but the first
+   *  token from the input stream
+   */
+  public PositionFilter(final TokenStream input, final int positionIncrement) {
+    this(input);
+    this.positionIncrement = positionIncrement;
+  }
+
+  @Override
+  public final boolean incrementToken() throws IOException {
+    if (input.incrementToken()) {
+      if (firstTokenPositioned) {
+        posIncrAtt.setPositionIncrement(positionIncrement);
+      } else {
+        firstTokenPositioned = true;
+      }
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  @Override
+  public void reset() throws IOException {
+    super.reset();
+    firstTokenPositioned = false;
+  }
+}