Indexing options

This page contains a description of all the properties of the IndexingOptions class.

setCancellation method

The setCancellation method is used to specify an object of type Cancellation, used to cancel of an index operation. The default value is null. An operation can be canceled if necessary with a time delay. Note that after cancellation, an index may not immediately stop an operation, but with a some delay.

The following example demonstrates cancelling of an indexing operation.

String indexFolder = "c:\\MyIndex\\";
String documentFolder = "c:\\MyDocuments\\";
 
// Creating an index in the specified folder
Index index = new Index(indexFolder);
 
// Creating an instance of indexing options
IndexingOptions options = new IndexingOptions();
options.setCancellation(new Cancellation()); // Setting a cancellation object
options.getCancellation().cancelAfter(300000); // Setting a time period of 300 seconds after which the indexing operation will be cancelled
 
// Indexing documents from the specified folder
index.add(documentFolder, options);

setAsync method

The setAsync method is used to specify whether to perform indexing operation asynchronously or synchronously. The default value is false, meaning synchronous execution. The example below demonstrates the performing of an asynchronous indexing.

String indexFolder = "c:\\MyIndex\\";
String documentFolder = "c:\\MyDocuments\\";
 
// Creating index in the specified folder
Index index = new Index(indexFolder);
 
// Subscribing to the event
index.getEvents().StatusChanged.add(new EventHandler<BaseIndexEventArgs>() {
    public void invoke(Object sender, BaseIndexEventArgs args) {
        if (args.getStatus() != IndexStatus.InProgress) {
            // A notification of the operation completion should be here
        }
    }
});
 
// Creating an instance of indexing options
IndexingOptions options = new IndexingOptions();
options.setAsync(true); // Specifying the asynchronous performing of the operation
 
// Indexing documents from the specified folder
// The method will return control before the indexing operation is completed
index.add(documentFolder, options);

setThreads method

The setThreads method is used to set the number of threads used for indexing. The default value is 1. The number of indexing threads cannot be less than 1 or more than 4.

A larger number of threads accelerates the indexing process. However, be careful when specifying the number of indexing threads more than 1, because the amount of memory used during indexing is directly proportional to the number of threads involved. If there is 4 GB of RAM or less in the system, using more than 1 thread may result in out of memory error. In addition, the hard disk where the files for indexing are located may be the bottleneck and performance will not increase.

The following example demonstrates how to perform indexing in 2 threads.

String indexFolder = "c:\\MyIndex\\";
String documentFolder = "c:\\MyDocuments\\";
 
// Creating an index in the specified folder
Index index = new Index(indexFolder);
 
// Creating an instance of indexing options
IndexingOptions options = new IndexingOptions();
options.setThreads(2); // Setting the number of indexing threads
 
// Indexing documents from the specified folder
index.add(documentFolder, options);

getMetadataIndexingOptions method

The getMetadataIndexingOptions method returns an instance of the MetadataIndexingOptions class. This class contains methods for setting metadata indexing options:

  • The setIndexingEmptyValues method sets a value indicating whether to index empty field values or not. The default value is true.
  • The setIndexingEmptyNames method sets a value indicating whether to index empty field names or not. The default value is true.
  • The setDefaultFieldName method sets the default field name used to index empty field names. The default value is “unknown”.
  • The setSeparatorInCompoundName method sets the separator in the compound name of a field. The default value is “.” (period character).
  • The setMaxBytesToIndexField method sets the maximum number of values indexed from an array of byte values. The default value is Integer.MAX_VALUE.
  • The setMaxIntsToIndexField method sets the maximum number of values indexed from an array of int values. The default value is Integer.MAX_VALUE.
  • The setMaxLongsToIndexField method sets the maximum number of values indexed from an array of long values. The default value is Integer.MAX_VALUE.
  • The setMaxDoublesToIndexField method sets the maximum number of values indexed from an array of double values. The default value is Integer.MAX_VALUE.
  • The setSeparatorBetweenValues method sets the separator between values in a field of type array. The default value is " " (space character).

The following example demonstrates how to set the metadata indexing options.

String indexFolder = "c:\\MyIndex";
String documentFolder = "c:\\MyDocuments";

// Creating an index
Index index = new Index(indexFolder);

// Setting the metadata indexing options
IndexingOptions options = new IndexingOptions();
options.getMetadataIndexingOptions().setDefaultFieldName("default");
options.getMetadataIndexingOptions().setSeparatorInCompoundName("\\");
options.getMetadataIndexingOptions().setMaxBytesToIndexField(10);
options.getMetadataIndexingOptions().setMaxIntsToIndexField(10);
options.getMetadataIndexingOptions().setMaxLongsToIndexField(10);
options.getMetadataIndexingOptions().setMaxDoublesToIndexField(10);

// Starting indexing operation
index.add(documentFolder, options);

More resources

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