Implementing a custom search algorithm

Overview

You can use the add-on's API to implement a custom search algorithm in Java. Administrators can use the algorithm when configuring the add-on. The following bullets highlight the requirements to implement a custom algorithm:

• Write the class that includes the logic for the search algorithm.

• Create a definition class.

• Register the definition class in your custom module.

Example algorithm class

The following sample class defines a custom search algorithm. This class must extend the SearchDistance abstract class. The getDistance() method is where you define how the add-on calculates the similarity between a search keyword and the data being searched.

public class MyContainsAlgorithm extends SearchDistance
{

	public MyContainsAlgorithm(SchemaNode schemaNode, Locale locale)

	{
		super(schemaNode, locale);
	}

	@Override
	public float getDistance(String keyword, String text)
	{
		if (text.contains(keyword))
		{
			return 100f;
		}
		return 0;
	}

	@Override
	public boolean isNumericSupported()
	{
		return false;
	}

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

	@Override
	public SearchComparator cloneMatching(SchemaNode newNode)
	{
		return new MyContainsAlgorithm(newNode, this.getLocale());
	}

}

Sample definition class

A definition class provides any labels, descriptions or parameters that will display in the UI during the configuration process. Additionally, this class instantiates the algorithm class from the previous section.

public class MyContainsAlgorithmDefinition implements AlgorithmDefinition
{

	@Override
	public UserMessage getLabel()
	{
		return UserMessage.createInfo("My Custom Algorithm");
	}

	@Override
	public UserMessage getDescription()
	{
		return UserMessage.createInfo("This is a custom algorith!");
	}

	@Override
	public List<ParameterDefinition> getParameters()
	{
		return null;
	}

	@Override
	public SearchComparator getAlgorithm(AlgorithmDefinitionContext adContext)
	{
		if (adContext == null)
		{
			return new MyContainsAlgorithm(null, Locale.US);
		}
		return new MyContainsAlgorithm(adContext.getField(), adContext.getLocale());
	}

	@Override
	public Class<SearchAlgorithmConfiguration> getSearchConfigurationClass()
	{
		return SearchAlgorithmConfiguration.class;
	}

	@Override
	public UserMessage checkParameterValueRange(List<InputParameter> parameters, Locale locale)
	{
		return null;
	}

}

Register the definition class

To register you definition class, add the following to the handleRepositoryStartup() method in your module's registration servlet.

private void registerTeseAlgorithms()
	{
		AlgorithmCatalog.add(new MyContainsAlgorithmDefinition());
	}