content: package org.apache.lucene.analysis;
  
  /**
   * 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 org.apache.lucene.util.AttributeSource;
  import org.apache.lucene.util.NumericUtils;
  import org.apache.lucene.document.NumericField; // for javadocs
  import org.apache.lucene.search.NumericRangeQuery; // for javadocs
  import org.apache.lucene.search.NumericRangeFilter; // for javadocs
  import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
  import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
  import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
  
  /**
   * <b>Expert:</b> This class provides a {@link TokenStream}
   * for indexing numeric values that can be used by {@link
   * NumericRangeQuery} or {@link NumericRangeFilter}.
   *
   * <p>Note that for simple usage, {@link NumericField} is
   * recommended.  {@link NumericField} disables norms and
   * term freqs, as they are not usually needed during
   * searching.  If you need to change these settings, you
   * should use this class.
   *
   * <p>See {@link NumericField} for capabilities of fields
   * indexed numerically.</p>
   *
   * <p>Here's an example usage, for an <code>int</code> field:
   *
   * <pre>
   *  Field field = new Field(name, new NumericTokenStream(precisionStep).setIntValue(value));
   *  field.setOmitNorms(true);
   *  field.setIndexOptions(IndexOptions.DOCS_ONLY);
   *  document.add(field);
   * </pre>
   *
   * <p>For optimal performance, re-use the TokenStream and Field instance
   * for more than one document:
   *
   * <pre>
   *  NumericTokenStream stream = new NumericTokenStream(precisionStep);
   *  Field field = new Field(name, stream);
   *  field.setOmitNorms(true);
   *  field.setIndexOptions(IndexOptions.DOCS_ONLY);
   *  Document document = new Document();
   *  document.add(field);
   *
   *  for(all documents) {
   *    stream.setIntValue(value)
   *    writer.addDocument(document);
   *  }
   * </pre>
   *
   * <p>This stream is not intended to be used in analyzers;
   * it's more for iterating the different precisions during
   * indexing a specific numeric value.</p>
  
   * <p><b>NOTE</b>: as token streams are only consumed once
   * the document is added to the index, if you index more
   * than one numeric field, use a separate <code>NumericTokenStream</code>
   * instance for each.</p>
   *
   * <p>See {@link NumericRangeQuery} for more details on the
   * <a
   * href="../search/NumericRangeQuery.html#precisionStepDesc"><code>precisionStep</code></a>
   * parameter as well as how numeric fields work under the hood.</p>
   *
   * @since 2.9
   */
  public final class NumericTokenStream extends TokenStream {
  
    /** The full precision token gets this token type assigned. */
    public static final String TOKEN_TYPE_FULL_PREC  = "fullPrecNumeric";
  
    /** The lower precision tokens gets this token type assigned. */
    public static final String TOKEN_TYPE_LOWER_PREC = "lowerPrecNumeric";
  
    /**
     * Creates a token stream for numeric values using the default <code>precisionStep</code>
     * {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). The stream is not yet initialized,
     * before using set a value using the various set<em>???</em>Value() methods.
     */
    public NumericTokenStream() {
      this(NumericUtils.PRECISION_STEP_DEFAULT);
    }
    
    /**
     * Creates a token stream for numeric values with the specified
     * <code>precisionStep</code>. The stream is not yet initialized,
     * before using set a value using the various set<em>???</em>Value() methods.
     */
    public NumericTokenStream(final int precisionStep) {
      super();
      this.precisionStep = precisionStep;
      if (precisionStep < 1)
        throw new IllegalArgumentException("precisionStep must be >=1");
    }
  
    /**
     * Expert: Creates a token stream for numeric values with the specified
     * <code>precisionStep</code> using the given {@link AttributeSource}.
     * The stream is not yet initialized,
     * before using set a value using the various set<em>???</em>Value() methods.
     */
    public NumericTokenStream(AttributeSource source, final int precisionStep) {
      super(source);
      this.precisionStep = precisionStep;
      if (precisionStep < 1)
        throw new IllegalArgumentException("precisionStep must be >=1");
    }
  
    /**
     * Expert: Creates a token stream for numeric values with the specified
     * <code>precisionStep</code> using the given
     * {@link org.apache.lucene.util.AttributeSource.AttributeFactory}.
     * The stream is not yet initialized,
     * before using set a value using the various set<em>???</em>Value() methods.
     */
    public NumericTokenStream(AttributeFactory factory, final int precisionStep) {
      super(factory);
      this.precisionStep = precisionStep;
      if (precisionStep < 1)
        throw new IllegalArgumentException("precisionStep must be >=1");
    }
  
    /**
     * Initializes the token stream with the supplied <code>long</code> value.
     * @param value the value, for which this TokenStream should enumerate tokens.
     * @return this instance, because of this you can use it the following way:
     * <code>new Field(name, new NumericTokenStream(precisionStep).setLongValue(value))</code>
     */
    public NumericTokenStream setLongValue(final long value) {
      this.value = value;
      valSize = 64;
      shift = 0;
      return this;
    }
    
    /**
     * Initializes the token stream with the supplied <code>int</code> value.
     * @param value the value, for which this TokenStream should enumerate tokens.
     * @return this instance, because of this you can use it the following way:
     * <code>new Field(name, new NumericTokenStream(precisionStep).setIntValue(value))</code>
     */
    public NumericTokenStream setIntValue(final int value) {
      this.value = value;
      valSize = 32;
      shift = 0;
      return this;
    }
    
    /**
     * Initializes the token stream with the supplied <code>double</code> value.
     * @param value the value, for which this TokenStream should enumerate tokens.
     * @return this instance, because of this you can use it the following way:
     * <code>new Field(name, new NumericTokenStream(precisionStep).setDoubleValue(value))</code>
     */
    public NumericTokenStream setDoubleValue(final double value) {
      this.value = NumericUtils.doubleToSortableLong(value);
      valSize = 64;
      shift = 0;
      return this;
    }
    
    /**
     * Initializes the token stream with the supplied <code>float</code> value.
     * @param value the value, for which this TokenStream should enumerate tokens.
     * @return this instance, because of this you can use it the following way:
     * <code>new Field(name, new NumericTokenStream(precisionStep).setFloatValue(value))</code>
     */
    public NumericTokenStream setFloatValue(final float value) {
      this.value = NumericUtils.floatToSortableInt(value);
      valSize = 32;
      shift = 0;
      return this;
    }
    
    @Override
    public void reset() {
      if (valSize == 0)
        throw new IllegalStateException("call set???Value() before usage");
      shift = 0;
    }
  
    @Override
    public boolean incrementToken() {
      if (valSize == 0)
        throw new IllegalStateException("call set???Value() before usage");
      if (shift >= valSize)
        return false;
  
      clearAttributes();
      final char[] buffer;
      switch (valSize) {
        case 64:
          buffer = termAtt.resizeBuffer(NumericUtils.BUF_SIZE_LONG);
          termAtt.setLength(NumericUtils.longToPrefixCoded(value, shift, buffer));
          break;
        
        case 32:
          buffer = termAtt.resizeBuffer(NumericUtils.BUF_SIZE_INT);
          termAtt.setLength(NumericUtils.intToPrefixCoded((int) value, shift, buffer));
          break;
        
        default:
          // should not happen
          throw new IllegalArgumentException("valSize must be 32 or 64");
      }
      
      typeAtt.setType((shift == 0) ? TOKEN_TYPE_FULL_PREC : TOKEN_TYPE_LOWER_PREC);
      posIncrAtt.setPositionIncrement((shift == 0) ? 1 : 0);
      shift += precisionStep;
      return true;
    }
    
    @Override
    public String toString() {
      final StringBuilder sb = new StringBuilder("(numeric,valSize=").append(valSize);
      sb.append(",precisionStep=").append(precisionStep).append(')');
      return sb.toString();
    }
  
    /** Returns the precision step. */
    public int getPrecisionStep() {
      return precisionStep;
    }
    
    // members
    private final CharTermAttribute termAtt = addAttribute(CharTermAttribute.class);
    private final TypeAttribute typeAtt = addAttribute(TypeAttribute.class);
    private final PositionIncrementAttribute posIncrAtt = addAttribute(PositionIncrementAttribute.class);
    
    private int shift = 0, valSize = 0; // valSize==0 means not initialized
    private final int precisionStep;
    
    private long value = 0L;
  }
  