org.apache.lucene.search
Interface FieldCache


public interface FieldCache

Expert: Maintains caches of term values.

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

Since:
lucene 1.4
Version:
$Id: FieldCache.java,v 1.1 2004/05/19 23:05:27 tjones Exp $
Author:
Tim Jones (Nacimiento Software)

Nested Class Summary
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
 java.lang.Object getAuto(IndexReader reader, java.lang.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.
 java.lang.Comparable[] getCustom(IndexReader reader, java.lang.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, java.lang.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.
 int[] getInts(IndexReader reader, java.lang.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.
 FieldCache.StringIndex getStringIndex(IndexReader reader, java.lang.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.
 java.lang.String[] getStrings(IndexReader reader, java.lang.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 Detail

STRING_INDEX

public static final int STRING_INDEX
Indicator for StringIndex values in the cache.

See Also:
Constant Field Values

DEFAULT

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

Method Detail

getInts

public int[] getInts(IndexReader reader,
                     java.lang.String field)
              throws java.io.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.
Throws:
java.io.IOException - If any error occurs.

getFloats

public float[] getFloats(IndexReader reader,
                         java.lang.String field)
                  throws java.io.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.
Throws:
java.io.IOException - If any error occurs.

getStrings

public java.lang.String[] getStrings(IndexReader reader,
                                     java.lang.String field)
                              throws java.io.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.
Throws:
java.io.IOException - If any error occurs.

getStringIndex

public FieldCache.StringIndex getStringIndex(IndexReader reader,
                                             java.lang.String field)
                                      throws java.io.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.
Throws:
java.io.IOException - If any error occurs.

getAuto

public java.lang.Object getAuto(IndexReader reader,
                                java.lang.String field)
                         throws java.io.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.
Throws:
java.io.IOException - If any error occurs.

getCustom

public java.lang.Comparable[] getCustom(IndexReader reader,
                                        java.lang.String field,
                                        SortComparator comparator)
                                 throws java.io.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.
Throws:
java.io.IOException - If any error occurs.


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