org.apache.lucene.search

Interface FieldCache

public interface FieldCache

Expert: Maintains caches of term values.

Created: May 19, 2004 11:13:14 AM

Version:
$Id: FieldCache.java 179605 2005-06-02 16:48:40Z cutting $
Author:
Tim Jones (Nacimiento Software)
Since:
lucene 1.4

Nested Class Summary

static interface
FieldCache.FloatParser
Interface to parse floats from document fields.
static interface
FieldCache.IntParser
Interface to parse ints from document fields.
static class
FieldCache.StringIndex
Expert: Stores term text values and document ordering data.

Field Summary

static FieldCache
DEFAULT
Expert: The cache used internally by sorting and range query classes.
static int
STRING_INDEX
Indicator for StringIndex values in the cache.

Method Summary

Object
getAuto(IndexReader reader, String field)
Checks the internal cache for an appropriate entry, and if none is found reads field to see if it contains integers, floats or strings, and then calls one of the other methods in this class to get the values.
Comparable[]
getCustom(IndexReader reader, String field, SortComparator comparator)
Checks the internal cache for an appropriate entry, and if none is found reads the terms out of field and calls the given SortComparator to get the sort values.
float[]
getFloats(IndexReader reader, String field)
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as floats and returns an array of size reader.maxDoc() of the value each document has in the given field.
float[]
getFloats(IndexReader reader, String field, FieldCache.FloatParser parser)
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as floats and returns an array of size reader.maxDoc() of the value each document has in the given field.
int[]
getInts(IndexReader reader, String field)
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as integers and returns an array of size reader.maxDoc() of the value each document has in the given field.
int[]
getInts(IndexReader reader, String field, FieldCache.IntParser parser)
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as integers and returns an array of size reader.maxDoc() of the value each document has in the given field.
FieldCache.StringIndex
getStringIndex(IndexReader reader, String field)
Checks the internal cache for an appropriate entry, and if none is found reads the term values in field and returns an array of them in natural order, along with an array telling which element in the term array each document uses.
String[]
getStrings(IndexReader reader, String field)
Checks the internal cache for an appropriate entry, and if none is found, reads the term values in field and returns an array of size reader.maxDoc() containing the value each document has in the given field.

Field Details

DEFAULT

public static final FieldCache DEFAULT
Expert: The cache used internally by sorting and range query classes.

STRING_INDEX

public static final int STRING_INDEX
Indicator for StringIndex values in the cache.
Field Value:
-1

Method Details

getAuto

public Object getAuto(IndexReader reader,
                      String field)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found reads field to see if it contains integers, floats or strings, and then calls one of the other methods in this class to get the values. For string values, a StringIndex is returned. After calling this method, there is an entry in the cache for both type AUTO and the actual found type.
Parameters:
reader - Used to get field values.
field - Which field contains the values.
Returns:
int[], float[] or StringIndex.

getCustom

public Comparable[] getCustom(IndexReader reader,
                              String field,
                              SortComparator comparator)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found reads the terms out of field and calls the given SortComparator to get the sort values. A hit in the cache will happen if reader, field, and comparator are the same (using equals()) as a previous call to this method.
Parameters:
reader - Used to get field values.
field - Which field contains the values.
comparator - Used to convert terms into something to sort by.
Returns:
Array of sort objects, one for each document.

getFloats

public float[] getFloats(IndexReader reader,
                         String field)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as floats and returns an array of size reader.maxDoc() of the value each document has in the given field.
Parameters:
reader - Used to get field values.
field - Which field contains the floats.
Returns:
The values in the given field for each document.

getFloats

public float[] getFloats(IndexReader reader,
                         String field,
                         FieldCache.FloatParser parser)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as floats and returns an array of size reader.maxDoc() of the value each document has in the given field.
Parameters:
reader - Used to get field values.
field - Which field contains the floats.
parser - Computes float for string values.
Returns:
The values in the given field for each document.

getInts

public int[] getInts(IndexReader reader,
                     String field)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as integers and returns an array of size reader.maxDoc() of the value each document has in the given field.
Parameters:
reader - Used to get field values.
field - Which field contains the integers.
Returns:
The values in the given field for each document.

getInts

public int[] getInts(IndexReader reader,
                     String field,
                     FieldCache.IntParser parser)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found, reads the terms in field as integers and returns an array of size reader.maxDoc() of the value each document has in the given field.
Parameters:
reader - Used to get field values.
field - Which field contains the integers.
parser - Computes integer for string values.
Returns:
The values in the given field for each document.

getStringIndex

public FieldCache.StringIndex getStringIndex(IndexReader reader,
                                             String field)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found reads the term values in field and returns an array of them in natural order, along with an array telling which element in the term array each document uses.
Parameters:
reader - Used to get field values.
field - Which field contains the strings.
Returns:
Array of terms and index into the array for each document.

getStrings

public String[] getStrings(IndexReader reader,
                           String field)
            throws IOException
Checks the internal cache for an appropriate entry, and if none is found, reads the term values in field and returns an array of size reader.maxDoc() containing the value each document has in the given field.
Parameters:
reader - Used to get field values.
field - Which field contains the strings.
Returns:
The values in the given field for each document.

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