Interface for custom field types 

The CustomFieldType interface marks Solr custom field types and provides their actual stored field type.

DataStax Enterprise implements a CustomFieldType interface that marks Solr custom field types and provides their actual stored field type. The custom field type stores an integer trie field as a string representing a comma separated list of integer values: when indexed, the string is split into its integer values, each one indexed as a trie integer field. This class effectively implements a multi-valued field based on its string representation.

A CustomFieldType can override this method to provide the FieldType for the binary response writer to look at when it determines whether to call the field's toObject(). This allows the binary response writer, for instance, to return java.util.Date in place of text for a CustomFieldType that extends TrieDateField.

To ensure that custom field types control their serialized value, use:
public Class<? extends FieldType> getKnownType() 
   {
     return getClass();
   }
See the example reference implementation.

Procedure

To use the CustomFieldType interface:

  1. Implement a custom field type class something like the following reference implementation.
  2. Export the class to a JAR, and place the JAR in this location:
    • Package installations: usr/share/dse
    • Installer-No Services and Tarball installations: install_location/resources/dse/lib
    The JAR is added to the CLASSPATH automatically.

Example

Reference implementation

Here is an example of a custom field type class:

package com.datastax.bdp.search.solr.functional;

import com.datastax.bdp.search.solr.CustomFieldType;
import java.util.ArrayList;
import java.util.List;
import org.apache.lucene.index.IndexableField;
import org.apache.solr.schema.FieldType;
import org.apache.solr.schema.SchemaField;
import org.apache.solr.schema.StrField;
import org.apache.solr.schema.TrieField;

public class CustomTestField extends TrieField implements CustomFieldType
{
    public CustomTestField()
    {
        this.type = TrieField.TrieTypes.INTEGER;
    }

    @Override
    public FieldType getStoredFieldType()
    {
        return new StrField();
    }

    @Override
    public boolean multiValuedFieldCache()
    {
        return true;
    }

    @Override
    public ListIndexableField createFields(SchemaField sf, Object value)
    {
        String[] values = ((String) value).split(" ");
        ListIndexableField fields = new ArrayListIndexableField();
        for (String v : values)
        {
            fields.add(createField(sf, v));
        }
        return fields;
    }

    @Override
    public String toInternal(String value)
    {
        return value;
    }

    @Override
    public String toExternal(IndexableField f)
    {
        return f.stringValue();
    } 
    
    public Class<? extends FieldType> getKnownType() 
    {
        return TrieField.class;
    }

}