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#Apache lucene search example update#

Build an IndexSearcher using the in-memory index Optimize and close the writer to finish building the index "Freedom is not worth having if it does not connote " + Writer.addDocument(createDocument("Mohandas Gandhi", "There is nothing to take a man's freedom away from " +

Writer.addDocument(createDocument("Ayn Rand", "which the achievements of our ends and welfare depend.")) "of all of us concerning a great many of the factors on " + "recognition of the inevitable and universal ignorance " + "The case for individual freedom rests largely on the " + Writer.addDocument(createDocument("Friedrich Hayek", "in the end, progress is accomplished by the man who does " + "critic, is of altogether secondary importance, and that, " + "It behooves every man to remember that the work of the " + Writer.addDocument(createDocument("Theodore Roosevelt", Add some Document objects containing quotes New IndexWriter(idx, new StandardAnalyzer(), true) Construct a RAMDirectory to hold the in-memory representation * A simple example of an in-memory search using Lucene.

The example in Figure 1 illustrates a minimal usage of the library. There are ways to customize practically every aspect of Lucene.

The Query object is passed to the IndexSearcher‘s search(…) method, which returns a Hits object that provides access to the Document objects that match the query.

These can be created using the QueryParser class.

A Query object encapulates the search query.

In this example, we pass in the RAMDirectory object that we created when the index was built.

As with IndexWriters, IndexSearchers can be constructed with a directory name for file-based indexes.

Search the index using an IndexSearcher object.

Somewhat unintuitively, adding and deleting Documents from an index is done with an IndexReader object.

#Apache lucene search example update#

Update the index, by either rebuilding it from scratch or deleting (and, where appropriate, re-adding) Documents.Optimize and close the IndexWriter object.Different subclasses of Field support indexed or unindexed content. A Document is a collection of Field objects. Add Document objects representing each object to be searched to the IndexWriter.In this example, however, we use the RAMDirectory class to maintain an in-memory index. For file-based indexes, a directory name can be passed to the IndexWriter constructor.The example below provides a simple illustration of this capability.Īt a minimum, using Lucene typically involves the following steps: For small collections, especially when running in an unsigned applet or WebStart application where disk access is not permitted, Lucene provides a mechanism for maintaining an in-memory index. Lucene provides a number of advanced capabilities “out of the box”, and can be extended to accomodate special needs.įor large text collections, you will almost always want to use disk-based indices that can be updated and reused across multiple executions of an application. The Lucene text search engine library (from the Apache Jakarta project) provides fast and flexible search capabilities that can be easily integrated into many kinds of applications.