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| <html> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> |
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| <body> |
| Codecs API: API for customization of the encoding and structure of the index. |
| |
| <p> |
| The Codec API allows you to customise the way the following pieces of index information are stored: |
| <ul> |
| <li>Postings lists - see {@link org.apache.lucene.codecs.PostingsFormat}</li> |
| <li>DocValues - see {@link org.apache.lucene.codecs.DocValuesFormat}</li> |
| <li>Stored fields - see {@link org.apache.lucene.codecs.StoredFieldsFormat}</li> |
| <li>Term vectors - see {@link org.apache.lucene.codecs.TermVectorsFormat}</li> |
| <li>FieldInfos - see {@link org.apache.lucene.codecs.FieldInfosFormat}</li> |
| <li>SegmentInfo - see {@link org.apache.lucene.codecs.SegmentInfoFormat}</li> |
| <li>Norms - see {@link org.apache.lucene.codecs.NormsFormat}</li> |
| <li>Live documents - see {@link org.apache.lucene.codecs.LiveDocsFormat}</li> |
| </ul> |
| </p> |
| |
| For some concrete implementations beyond Lucene's official index format, see |
| the <a href="{@docRoot}/../codecs/overview-summary.html">Codecs module</a>. |
| |
| <p> |
| Codecs are identified by name through the Java Service Provider Interface. To create your own codec, extend |
| {@link org.apache.lucene.codecs.Codec} and pass the new codec's name to the super() constructor: |
| <pre class="prettyprint"> |
| public class MyCodec extends Codec { |
| |
| public MyCodec() { |
| super("MyCodecName"); |
| } |
| |
| ... |
| } |
| </pre> |
| You will need to register the Codec class so that the {@link java.util.ServiceLoader ServiceLoader} can find it, by including a |
| META-INF/services/org.apache.lucene.codecs.Codec file on your classpath that contains the package-qualified |
| name of your codec. |
| </p> |
| |
| <p> |
| If you just want to customise the {@link org.apache.lucene.codecs.PostingsFormat}, or use different postings |
| formats for different fields, then you can register your custom postings format in the same way (in |
| META-INF/services/org.apache.lucene.codecs.PostingsFormat), and then extend the default |
| {@link org.apache.lucene.codecs.lucene46.Lucene46Codec} and override |
| {@link org.apache.lucene.codecs.lucene46.Lucene46Codec#getPostingsFormatForField(String)} to return your custom |
| postings format. |
| </p> |
| <p> |
| Similarly, if you just want to customise the {@link org.apache.lucene.codecs.DocValuesFormat} per-field, have |
| a look at {@link org.apache.lucene.codecs.lucene46.Lucene46Codec#getDocValuesFormatForField(String)}. |
| </p> |
| </body> |
| </html> |
