Class DefaultCodecFactory

Implements the default functionality of ICodecFactory.

To replace the DefaultCodecFactory instance, call SetCodecFactory(ICodecFactory) at application start up. DefaultCodecFactory can be subclassed or passed additional parameters to register additional codecs, inject dependencies, or change caching behavior, as shown in the following examples. Alternatively, ICodecFactory can be implemented to provide complete control over codec creation and lifetimes.

Register Additional Codecs

Additional codecs can be added by initializing the instance of DefaultCodecFactory and passing an array of Codec-derived types.

// Register the factory at application start up.
Codec.SetCodecFactory(new DefaultCodecFactory {
    CustomCodecTypes = new Type[] { typeof(MyCodec), typeof(AnotherCodec) }
});

Only Use Explicitly Defined Codecs

PutCodecType(Type) can be used to explicitly add codec types. In this example, the call to base.Initialize() is excluded to skip the built-in codec registration. Since AnotherCodec doesn't have a default constructor, the NewCodec(Type) method is overridden to supply the required parameters.

public class ExplicitCodecFactory : DefaultCodecFactory
{
    protected override void Initialize()
    {
        // Load specific codecs in a specific order.
        PutCodecType(typeof(MyCodec));
        PutCodecType(typeof(AnotherCodec));
    }

    protected override Codec NewCodec(Type type)
    {
        // Special case: AnotherCodec has a required dependency
        if (typeof(AnotherCodec).Equals(type))
            return new AnotherCodec(new SomeDependency());

        return base.NewCodec(type);
    }
}

// Register the factory at application start up.
Codec.SetCodecFactory(new ExplicitCodecFactory());

See the Lucene.Net.Codecs namespace documentation for more examples of how to inject dependencies into Codec subclasses.

Use Reflection to Scan an Assembly for Codecs

ScanForCodecs(Assembly) or ScanForCodecs(IEnumerable<Assembly>) can be used to scan assemblies using .NET Reflection for codec types and add all subclasses that are found automatically. This example calls base.Initialize() to load the default codecs prior to scanning for additional codecs.

public class ScanningCodecFactory : DefaultCodecFactory
{
    protected override void Initialize()
    {
        // Load all default codecs
        base.Initialize();

        // Load all of the codecs inside of the same assembly that MyCodec is defined in
        ScanForCodecs(typeof(MyCodec).Assembly);
    }
}

// Register the factory at application start up.
Codec.SetCodecFactory(new ScanningCodecFactory());

Codecs in the target assemblie(s) can be excluded from the scan by decorating them with the ExcludeCodecFromScanAttribute.

Inheritance

System.Object

NamedServiceFactory<Codec>

DefaultCodecFactory

Implements

ICodecFactory

IServiceListable

Inherited Members

NamedServiceFactory<Codec>.m_initializationLock

NamedServiceFactory<Codec>.EnsureInitialized()

NamedServiceFactory<Codec>.CodecsAssembly

NamedServiceFactory<Codec>.IsServiceType(Type)

NamedServiceFactory<Codec>.GetServiceName(Type)

NamedServiceFactory<Codec>.GetCanonicalName(Type)

NamedServiceFactory<Codec>.IsFullyTrusted

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ReferenceEquals(System.Object, System.Object)

System.Object.ToString()

Namespace: Lucene.Net.Codecs

Assembly: Lucene.Net.dll

Syntax

public class DefaultCodecFactory : NamedServiceFactory<Codec>, ICodecFactory, IServiceListable

Constructors

DefaultCodecFactory()

Creates a new instance of DefaultCodecFactory.

Declaration

public DefaultCodecFactory()

Properties

AvailableServices

Gets a list of the available Codecs (by name).

Declaration

public virtual ICollection<string> AvailableServices { get; }

Property Value

Type	Description
System.Collections.Generic.ICollection<System.String>	A ICollection{string} of Codec names.

CustomCodecTypes

An array of custom Codec-derived types to be registered. This property can be initialized during construction of DefaultCodecFactory to make your custom codecs known to Lucene.

These types will be registered after the default Lucene types, so if a custom type has the same name as a Lucene Codec (via CodecNameAttribute) the custom type will replace the Lucene type with the same name.

Declaration

public IEnumerable<Type> CustomCodecTypes { get; set; }

Property Value

Type	Description
System.Collections.Generic.IEnumerable<System.Type>

Methods

GetCodec(String)

Gets the Codec instance from the provided name.

Declaration

public virtual Codec GetCodec(string name)

Parameters

Type	Name	Description
System.String	name	The name of the Codec instance to retrieve.

Returns

Type	Description
Codec	The Codec instance.

GetCodec(Type)

Gets the Codec instance from the provided type.

Declaration

protected virtual Codec GetCodec(Type type)

Parameters

Type	Name	Description
System.Type	type	The System.Type of Codec to retrieve.

Returns

Type	Description
Codec	The Codec instance.

GetCodecType(String)

Gets the Codec System.Type from the provided name.

Declaration

protected virtual Type GetCodecType(string name)

Parameters

Type	Name	Description
System.String	name	The name of the Codec System.Type to retrieve.

Returns

Type	Description
System.Type	The Codec System.Type.

Initialize()

Initializes the codec type cache with the known Codec types. Override this method (and optionally call base.Initialize()) to add your own Codec types by calling PutCodecType(Type) or ScanForCodecs(Assembly).

If two types have the same name by using the CodecNameAttribute, the last one registered wins.

Declaration

protected override void Initialize()

Overrides

Lucene.Net.Util.NamedServiceFactory<Lucene.Net.Codecs.Codec>.Initialize()

NewCodec(Type)

Instantiates a Codec based on the provided type.

Declaration

protected virtual Codec NewCodec(Type type)

Parameters

Type	Name	Description
System.Type	type	The System.Type of Codec to instantiate.

Returns

Type	Description
Codec	The new instance.

PutCodecType(Type)

Adds a Codec type to the Lucene.Net.Codecs.DefaultCodecFactory.codecNameToTypeMap, using the name provided in the CodecNameAttribute, if present, or the name of the codec class minus the "Codec" suffix as the name by default.

Note that if a Codec with the same name already exists in the map, calling this method will update it to the new type.

Declaration

protected virtual void PutCodecType(Type codec)

Parameters

Type	Name	Description
System.Type	codec	A type that subclasses Codec.

ScanForCodecs(IEnumerable<Assembly>)

Scans the given assemblies for subclasses of Codec and adds their names to the Lucene.Net.Codecs.DefaultCodecFactory.codecNameToTypeMap. Note that names will be automatically overridden if the Codec name appears multiple times - the last match wins.

Declaration

protected virtual void ScanForCodecs(IEnumerable<Assembly> assemblies)

Parameters

Type	Name	Description
System.Collections.Generic.IEnumerable<System.Reflection.Assembly>	assemblies	A list of assemblies to scan. The assemblies will be scanned from first to last, and the last match for each Codec name wins.

ScanForCodecs(Assembly)

Scans the given assembly for subclasses of Codec and adds their names to the Lucene.Net.Codecs.DefaultCodecFactory.codecNameToTypeMap. Note that names will be automatically overridden if the Codec name appears multiple times - the last match wins.

Declaration

protected virtual void ScanForCodecs(Assembly assembly)

Parameters

Type	Name	Description
System.Reflection.Assembly	assembly	The assembly to scan.

Implements

ICodecFactory

IServiceListable

See Also

ICodecFactory

IServiceListable

ExcludeCodecFromScanAttribute