Indexer Component

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The Indexer component enables the creation and modification of search indexes.

Syntax

nsoftware.IPWorksSearch.Indexer

Remarks

The Indexer component provides a simple way to create and manage Lucene 4.8 search indexes. The component is able to perform indexing operations such as adding, updating, and deleting index documents. It supports indexing operations with a wide variety of analyzers to allow for flexible control over the indexing process.

Preparing the Index

If IndexPath does not point to a pre-existing search index, the component will create a new one at the specified location before loading it. component.IndexPath = "PATH\\TO\\INDEX"; // Specify the path to the search index component.OpenIndex(); // Load the index

It is important to note that the OpenIndex method will load a snapshot of the index at the time it was opened. Any external changes made to the index afterwards will not be visible to the component until the method is called again. OpenIndex can be called multiple times to reload the index and reflect its latest changes in indexing operations.

Creating Documents

Deleting Documents

Documents that contain a specific field can be deleted from the index via the Delete method. // Deletes every document with a field that has a name of "field1" and a value of "Sample content for field 1" component.Delete("field1", "Sample content for field 1");

To delete all of the documents from the search index, call the DeleteAll method. // Delete all of the documents from the index component.DeleteAll();

Saving the Index

Property List

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.

Method List

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.

Event List

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.

Config Settings

The following is a list of config settings for the component with short descriptions. Click on the links for further details.

Analyzer Property (Indexer Component)

The global analyzer for the search index.

Syntax

• C#
• VB.NET

public IndexerAnalyzers Analyzer { get; set; }

enum IndexerAnalyzers {
  atStandard,
  atStop,
  atWhitespace,
  atSimple,
  atEmail
}

Public Property Analyzer As IndexerAnalyzers

Enum IndexerAnalyzers
  atStandard
  atStop
  atWhitespace
  atSimple
  atEmail
End Enum

Default Value

1

Remarks

Specifies the global analyzer for the document fields in the search index. Individual document fields may specify their own local analyzer types to override this global one. Please refer to the AnalyzerType field of the DocumentField type for more details.

Possible values are:

Analyzers and Tokenization

The way tokens are created directly affects the precision and relevance of search results. For example, if an analyzer does not break down the terms "WORD" and "word" as the same value, searches for one may not bring up results for the other.

Stop Words

The full list of stop words that are ignored by these analyzers can be found below:

a, an, and, are, as, at, be, but, by, for, if, in, into, is, it, no, not, of, on,
or, such, that, the, their, then, there, these, they, this, to, was, will, with

This property is not available at design time.

Fields Property (Indexer Component)

A collection of document fields for updating and creating documents.

Syntax

• C#
• VB.NET

public FieldList Fields { get; }

Public Property Fields As FieldList

Remarks

Contains a list of document fields that make up the document that gets added to the search index when calling IndexDocument or Update. A document field can be added by accessing this property directly, or by calling the AddDocumentField method.

This property is not available at design time.

IndexPath Property (Indexer Component)

The path to the search index.

Syntax

• C#
• VB.NET

public string IndexPath { get; set; }

Public Property IndexPath As String

Default Value

""

Remarks

The filesystem path to the search index. This property must be specified before calling the OpenIndex method.

This value can either be a path to a pre-existing search index in the Lucene 4.8 index format, or a path to a directory where the index will be stored.

Loading or Creating a Search Index

If the specified directory does not exist, the component will attempt to create a new one at the specified location before creating the search index.

Example: component.IndexPath = "PATH\\TO\\INDEX"; // Specify the path to the search index component.OpenIndex(); // Load the index // ... Perform operations on the index ... component.CloseIndex();

Relative and Absolute Paths

This property is not available at design time.

AddDocumentField Method (Indexer Component)

Creates a document field.

Syntax

• C#
• VB.NET

public void AddDocumentField(string name, bool store, int type, string value, int analyzerType);

Public Sub AddDocumentField(ByVal Name As String, ByVal Store As Boolean, ByVal Type As Integer, ByVal Value As String, ByVal AnalyzerType As Integer)

Remarks

Creates a document field and adds it to the Fields collection.

Name specifies the name of the document field. This value acts as an identifier for the field and does not have to be unique.

Store determines if the field Text value will be stored in the index. Fields that are not stored in the index can be searched, but their full text contents will not be retrievable in search results. This value is only applicable when the field Type is set to ftText.

Type indicates the type of field that will be created. Its value determines how the field is indexed. Possible values are:

Text specifies the text contents of the field.

AnalyzerType specifies the analyzer for the field. This value determines how the field Text is analyzed and broken down into tokens when it is indexed. This parameter is only applicable when the field Type is set to ftText. Otherwise, this parameter is ignored.

Possible values are:

Analyzers and Tokenization

The way tokens are created directly affects the precision and relevance of search results. For example, if an analyzer does not break down the terms "WORD" and "word" as the same value, searches for one may not bring up results for the other.

Example (Create a new document with a single field): // text field component.AddDocumentField("company", true, (int)TFieldTypes.ftText, "nsoftware", (int)SearchIndexAnalyzerTypes.atStandard); // create a new document from the added fields and add it to the index component.IndexDocument();

Example (Create a new document with multiple fields): // text field component.AddDocumentField("author", true, (int)TFieldTypes.ftText, "Generic Design Patterns", (int)SearchIndexAnalyzerTypes.atStandard); // string field component.AddDocumentField("code", true, (int)TFieldTypes.ftString, "GDP2024", (int)SearchIndexAnalyzerTypes.atStandard); // int field component.AddDocumentField("edition", true, (int)TFieldTypes.ftInt32, "2", (int)SearchIndexAnalyzerTypes.atStandard); // create the document and add it to the index // the added document will be comprised of all of the fields in the DocumentFields collection component.IndexDocument();

CloseIndex Method (Indexer Component)

Commits and saves the changes made to the search index.

Syntax

• C#
• VB.NET

public void CloseIndex();

Public Sub CloseIndex()

Remarks

Commits the changes made to the search index and saves them to the location specified by IndexPath.

Config Method (Indexer Component)

Sets or retrieves a configuration setting.

Syntax

• C#
• VB.NET

public string Config(string configurationString);

Public Function Config(ByVal ConfigurationString As String) As String

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Delete Method (Indexer Component)

Deletes documents from the search index.

Syntax

• C#
• VB.NET

public void Delete(string fieldName, string fieldValue);

Public Sub Delete(ByVal FieldName As String, ByVal FieldValue As String)

Remarks

Deletes documents that contain a specific field from the search index.

FieldName specifies the name of the field that will be used to determine the documents that will be deleted.

FieldValue specifies the exact text content of the field that will be used to determine the documents that will be deleted. A document must have a field with this exact value and the name specified in the FieldName parameter for it to be affected by this method.

Example: // Delete every document in the index that has a field named "content" with a value of "Sample data" component.Delete("content", "Sample data");

DeleteAll Method (Indexer Component)

Deletes all of the documents from the search index.

Syntax

• C#
• VB.NET

public void DeleteAll();

Public Sub DeleteAll()

Remarks

Deletes all of the documents from the search index.

IndexDocument Method (Indexer Component)

Creates a new document and adds it to the search index.

Syntax

• C#
• VB.NET

public void IndexDocument();

Public Sub IndexDocument()

Remarks

Creates a new document and adds it to the search index. Its document fields will be the same as the ones in the Fields collection when this method is called.

Example (Create a new document with a single field): // text field component.AddDocumentField("company", true, (int)TFieldTypes.ftText, "nsoftware", (int)SearchIndexAnalyzerTypes.atStandard); // create a new document from the added fields and add it to the index component.IndexDocument();

Example (Create a new document with multiple fields): // text field component.AddDocumentField("author", true, (int)TFieldTypes.ftText, "Generic Design Patterns", (int)SearchIndexAnalyzerTypes.atStandard); // string field component.AddDocumentField("code", true, (int)TFieldTypes.ftString, "GDP2024", (int)SearchIndexAnalyzerTypes.atStandard); // int field component.AddDocumentField("edition", true, (int)TFieldTypes.ftInt32, "2", (int)SearchIndexAnalyzerTypes.atStandard); // create the document and add it to the index // the added document will be comprised of all of the fields in the DocumentFields collection component.IndexDocument();

OpenIndex Method (Indexer Component)

Opens an existing search index or creates a new one.

Syntax

• C#
• VB.NET

public void OpenIndex();

Public Sub OpenIndex()

Remarks

Loads the search index located in IndexPath and prepares it for modifications. This method should be called at least once before making changes to the search index via IndexDocument, Delete, DeleteAll, or Update. To save the changes and close the index, call CloseIndex instead.

Loading or Creating a Search Index

If the specified directory does not exist, the component will attempt to create a new one at the specified location before creating the search index.

Example: component.IndexPath = "PATH\\TO\\INDEX"; // Specify the path to the search index component.OpenIndex(); // Load the index // ... Perform operations on the index ... component.CloseIndex();

Index Updates

This method can be called multiple times to reload the index and reflect its latest changes in indexing operations.

Example:

component.OpenIndex(); // Load the search index // ... Perform operations on the index ... component.OpenIndex(); // Reload the index to reflect any new updates

Reset Method (Indexer Component)

Resets the component.

Syntax

• C#
• VB.NET

public void Reset();

Public Sub Reset()

Remarks

Resets the component's properties to their default values.

Update Method (Indexer Component)

Updates documents in the search index.

Syntax

• C#
• VB.NET

public void Update(string fieldName, string fieldValue);

Public Sub Update(ByVal FieldName As String, ByVal FieldValue As String)

Remarks

Updates documents in the search index. When this method is called, every document in the index that contains the specified field will be deleted. Once deleted, a new document with the fields in the Fields collection will be created and added to the index to replace the deleted documents. This is effectively the same as calling Delete followed by IndexDocument.

FieldName specifies the name of the field that will be used to identify the documents that will be updated.

FieldValue specifies the exact text content of the field that will be used to identify the documents that will be updated. A document must have a field with this exact value and the name specified in the FieldName parameter for it to be affected by this method.

Example (Update a document that has incorrect fields) // Assuming the index has a document with a field named "data" // and a value of "incorrect data" // Add the fields we want for the updated document component.AddDocumentField("data", true, 1, "corrected data"); component.AddDocumentField("company", "nsoftware"); // Delete the incorrect docuement and replace it with the new one // // If the index contains multiple documents with this field, they // will all be deleted, but only one document will be created to // replace them component.Update("data", "incorrect data");

Error Event (Indexer Component)

Fires to provide information about errors during indexing.

Syntax

• C#
• VB.NET

public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, IndexerErrorEventArgs e);

public class IndexerErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As IndexerErrorEventArgs)

Public Class IndexerErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

Fires in case of exceptional conditions during indexing. Normally, the component will raise an exception instead.

ErrorCode contains an error code and Description contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Log Event (Indexer Component)

This event fires once for each log message.

Syntax

• C#
• VB.NET

public event OnLogHandler OnLog;

public delegate void OnLogHandler(object sender, IndexerLogEventArgs e);

public class IndexerLogEventArgs : EventArgs {
  public int LogLevel { get; }
  public string Message { get; }
  public string LogType { get; }
}

Public Event OnLog As OnLogHandler

Public Delegate Sub OnLogHandler(sender As Object, e As IndexerLogEventArgs)

Public Class IndexerLogEventArgs Inherits EventArgs
  Public ReadOnly Property LogLevel As Integer
  Public ReadOnly Property Message As String
  Public ReadOnly Property LogType As String
End Class

Remarks

This event fires once for each log message generated by the component. The verbosity is controlled by the LogLevel setting.

LogLevel indicates the level of detail of the log message. Possible values are:

Message is the log entry.

LogType identifies the type of log entry.

Field Type

Holds information about a document field.

Remarks

This is used to access the data associated with a single document field.

Fields

Constructors

• C#
• VB.NET

public Field();

Public Field()

• C#
• VB.NET

public Field(string name, bool store, int type, string inputFile, string inputText, System.IO.Stream inputStream, int analyzerType);

Public Field(ByVal Name As String, ByVal Store As Boolean, ByVal Type As Integer, ByVal InputFile As String, ByVal InputText As String, ByVal InputStream As System.IO.Stream, ByVal AnalyzerType As Integer)

Config Settings (Indexer Component)

Indexer Config Settings

Base Config Settings

Trappable Errors (Indexer Component)