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. * *
See {@link NumericField} for capabilities of fields * indexed numerically.
* *Here's an example usage, for an int field:
*
*
* Field field = new Field(name, new NumericTokenStream(precisionStep).setIntValue(value)); * field.setOmitNorms(true); * field.setOmitTermFreqAndPositions(true); * document.add(field); ** *
For optimal performance, re-use the TokenStream and Field instance * for more than one document: * *
* NumericTokenStream stream = new NumericTokenStream(precisionStep);
* Field field = new Field(name, stream);
* field.setOmitNorms(true);
* field.setOmitTermFreqAndPositions(true);
* Document document = new Document();
* document.add(field);
*
* for(all documents) {
* stream.setIntValue(value)
* writer.addDocument(document);
* }
*
*
* This stream is not intended to be used in analyzers; * it's more for iterating the different precisions during * indexing a specific numeric value.
*NOTE: 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 NumericTokenStream
* instance for each.
See {@link NumericRangeQuery} for more details on the
* precisionStep
* parameter as well as how numeric fields work under the hood.
NOTE: This API is experimental and
* might change in incompatible ways in the next release.
*
* @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 precisionStep
* {@link NumericUtils#PRECISION_STEP_DEFAULT} (4). The stream is not yet initialized,
* before using set a value using the various set???Value() methods.
*/
public NumericTokenStream() {
this(NumericUtils.PRECISION_STEP_DEFAULT);
}
/**
* Creates a token stream for numeric values with the specified
* precisionStep. The stream is not yet initialized,
* before using set a value using the various set???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
* precisionStep using the given {@link AttributeSource}.
* The stream is not yet initialized,
* before using set a value using the various set???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
* precisionStep 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???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 long 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:
* new Field(name, new NumericTokenStream(precisionStep).setLongValue(value))
*/
public NumericTokenStream setLongValue(final long value) {
this.value = value;
valSize = 64;
shift = 0;
return this;
}
/**
* Initializes the token stream with the supplied int 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:
* new Field(name, new NumericTokenStream(precisionStep).setIntValue(value))
*/
public NumericTokenStream setIntValue(final int value) {
this.value = (long) value;
valSize = 32;
shift = 0;
return this;
}
/**
* Initializes the token stream with the supplied double 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:
* new Field(name, new NumericTokenStream(precisionStep).setDoubleValue(value))
*/
public NumericTokenStream setDoubleValue(final double value) {
this.value = NumericUtils.doubleToSortableLong(value);
valSize = 64;
shift = 0;
return this;
}
/**
* Initializes the token stream with the supplied float 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:
* new Field(name, new NumericTokenStream(precisionStep).setFloatValue(value))
*/
public NumericTokenStream setFloatValue(final float value) {
this.value = (long) 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.resizeTermBuffer(NumericUtils.BUF_SIZE_LONG);
termAtt.setTermLength(NumericUtils.longToPrefixCoded(value, shift, buffer));
break;
case 32:
buffer = termAtt.resizeTermBuffer(NumericUtils.BUF_SIZE_INT);
termAtt.setTermLength(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();
}
// members
private final TermAttribute termAtt = addAttribute(TermAttribute.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;
}