org.carrot2.source.opensearch
Class OpenSearchDocumentSource

java.lang.Object
  org.carrot2.core.ProcessingComponentBase
      org.carrot2.source.SearchEngineBase
          org.carrot2.source.MultipageSearchEngine
              org.carrot2.source.opensearch.OpenSearchDocumentSource

All Implemented Interfaces:

IDocumentSource, IProcessingComponent

public class OpenSearchDocumentSource
extends MultipageSearchEngine

A IDocumentSource fetching Documents (search results) from an OpenSearch feed.

Based on code donated by Julien Nioche.

See Also:

OpenSearch.org

Nested Class Summary

Nested classes/interfaces inherited from class org.carrot2.source.MultipageSearchEngine

MultipageSearchEngine.SearchEngineResponseCallable, MultipageSearchEngine.SearchMode, MultipageSearchEngine.SearchRange

Field Summary

Map<String,String>	feedUrlParams Additional parameters to be appended to feedUrlTemplate on each request.
String	feedUrlTemplate URL to fetch the search feed from.
int	maximumResults Maximum number of results.
int	resultsPerPage Results per page.
String	userAgent User agent header.

Fields inherited from class org.carrot2.source.MultipageSearchEngine

searchMode

Fields inherited from class org.carrot2.source.SearchEngineBase

compressed, documents, query, results, resultsTotal, start, statistics

Constructor Summary

OpenSearchDocumentSource()

Method Summary

void	beforeProcessing() Invoked after the attributes marked with Processing and Input annotations have been bound, but before a call to IProcessingComponent.process().
protected Callable<SearchEngineResponse>	createFetcher(MultipageSearchEngine.SearchRange bucket) Subclasses should override this method and return a MultipageSearchEngine.SearchEngineResponseCallable instance that fetches search results in the given range.
void	process() Performs the processing required to fulfill the request.

Methods inherited from class org.carrot2.source.MultipageSearchEngine

collectDocuments, process, runQuery

Methods inherited from class org.carrot2.source.SearchEngineBase

afterFetch, clean, urlEncode

Methods inherited from class org.carrot2.core.ProcessingComponentBase

afterProcessing, dispose, getContext, getSharedExecutor, init

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface org.carrot2.core.IProcessingComponent

afterProcessing, dispose, init

Field Detail

feedUrlTemplate

public String feedUrlTemplate

URL to fetch the search feed from. The URL template can contain variable place holders as defined by the OpenSearch specification that will be replaced during runtime. The format of the place holder is ${variable}. The following variables are supported:

• searchTerms will be replaced by the query
• startIndex index of the first result to be searched. Mutually exclusive with startPage
.
• startPage index of the first result to be searched. Mutually exclusive with startIndex.
• count the number of search results per page

Example URL feed templates for public services:

nature.com

http://www.nature.com/opensearch/request?interface=opensearch&operation=searchRetrieve&query=${searchTerms}&startRecord=${startIndex}&maximumRecords=${count}&httpAccept=application/rss%2Bxml

indeed.com

http://www.indeed.com/opensearch?q=${searchTerms}&start=${startIndex}&limit=${count}

Attribute label:

Feed URL template

Attribute level:

Basic

Attribute group:

Service

resultsPerPage

public int resultsPerPage

Results per page. The number of results per page the document source will expect the feed to return.

Attribute label:

Results per page

Attribute level:

Basic

Attribute group:

Service

maximumResults

public int maximumResults

Maximum number of results. The maximum number of results the document source can deliver.

Attribute label:

Maximum results

Attribute level:

Basic

Attribute group:

Service

feedUrlParams

public Map<String,String> feedUrlParams

Additional parameters to be appended to feedUrlTemplate on each request.

Attribute label:

Feed URL parameters

Attribute level:

Advanced

Attribute group:

Service

userAgent

public String userAgent

User agent header. The contents of the User-Agent HTTP header to use when making requests to the feed URL. If empty or null value is provided, the following User-Agent will be sent: Rome Client (http://tinyurl.com/64t5n) Ver: UNKNOWN.

Attribute label:

User agent

Attribute level:

Advanced

Attribute group:

Service

Constructor Detail

OpenSearchDocumentSource

public OpenSearchDocumentSource()

Method Detail

beforeProcessing

public void beforeProcessing()

Description copied from interface: IProcessingComponent

Invoked after the attributes marked with Processing and Input annotations have been bound, but before a call to IProcessingComponent.process(). In this method, the processing component should perform any initializations based on the runtime attributes. This method is called once per request.

Specified by:

beforeProcessing in interface IProcessingComponent

Overrides:

beforeProcessing in class ProcessingComponentBase

process

public void process()
             throws ProcessingException

Description copied from interface: IProcessingComponent

Performs the processing required to fulfill the request. This method is called once per request.

Specified by:

process in interface IProcessingComponent

Overrides:

process in class ProcessingComponentBase

Throws:

ProcessingException - when processing failed. If thrown, the IProcessingComponent.afterProcessing() method will be called and the component will be ready to accept further requests or to be disposed of. Finally, the exception will be rethrown from the controller method that caused the component to perform processing.

createFetcher

protected Callable<SearchEngineResponse> createFetcher(MultipageSearchEngine.SearchRange bucket)

Description copied from class: MultipageSearchEngine

Subclasses should override this method and return a MultipageSearchEngine.SearchEngineResponseCallable instance that fetches search results in the given range.

Note the query (if any is required) should be passed at the concrete class level. We are not concerned with it here.

Specified by:

createFetcher in class MultipageSearchEngine

Parameters:

bucket - The search range to fetch.