pylucene 3.5.0-3

[pylucene.git] / lucene-java-3.5.0 / lucene / contrib / analyzers / smartcn / src / java / org / apache / lucene / analysis / cn / smart / WordTokenFilter.java

diff --git a/lucene-java-3.5.0/lucene/contrib/analyzers/smartcn/src/java/org/apache/lucene/analysis/cn/smart/WordTokenFilter.java b/lucene-java-3.5.0/lucene/contrib/analyzers/smartcn/src/java/org/apache/lucene/analysis/cn/smart/WordTokenFilter.java
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+++ b/lucene-java-3.5.0/lucene/contrib/analyzers/smartcn/src/java/org/apache/lucene/analysis/cn/smart/WordTokenFilter.java
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+/**
+ * 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.
+ */
+
+package org.apache.lucene.analysis.cn.smart;
+
+import java.io.IOException;
+import java.util.Iterator;
+import java.util.List;
+
+import org.apache.lucene.analysis.TokenFilter;
+import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.cn.smart.hhmm.SegToken;
+import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
+import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
+import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
+
+/**
+ * A {@link TokenFilter} that breaks sentences into words.
+ * @lucene.experimental
+ */
+public final class WordTokenFilter extends TokenFilter {
+
+  private WordSegmenter wordSegmenter;
+
+  private Iterator<SegToken> tokenIter;
+
+  private List<SegToken> tokenBuffer;
+  
+  private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
+  private final OffsetAttribute offsetAtt = addAttribute(OffsetAttribute.class);
+  private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class);
+
+  /**
+   * Construct a new WordTokenizer.
+   * 
+   * @param in {@link TokenStream} of sentences 
+   */
+  public WordTokenFilter(TokenStream in) {
+    super(in);
+    this.wordSegmenter = new WordSegmenter();
+  }
+  
+  @Override
+  public boolean incrementToken() throws IOException {   
+    if (tokenIter == null || !tokenIter.hasNext()) {
+      // there are no remaining tokens from the current sentence... are there more sentences?
+      if (input.incrementToken()) {
+        // a new sentence is available: process it.
+        tokenBuffer = wordSegmenter.segmentSentence(termAtt.toString(), offsetAtt.startOffset());
+        tokenIter = tokenBuffer.iterator();
+        /* 
+         * it should not be possible to have a sentence with 0 words, check just in case.
+         * returning EOS isn't the best either, but its the behavior of the original code.
+         */
+        if (!tokenIter.hasNext())
+          return false;
+      } else {
+        return false; // no more sentences, end of stream!
+      }
+    } 
+    // WordTokenFilter must clear attributes, as it is creating new tokens.
+    clearAttributes();
+    // There are remaining tokens from the current sentence, return the next one. 
+    SegToken nextWord = tokenIter.next();
+    termAtt.copyBuffer(nextWord.charArray, 0, nextWord.charArray.length);
+    offsetAtt.setOffset(nextWord.startOffset, nextWord.endOffset);
+    typeAtt.setType("word");
+    return true;
+  }
+
+  @Override
+  public void reset() throws IOException {
+    super.reset();
+    tokenIter = null;
+  }
+}