Book Image

Apache Solr for Indexing Data

Book Image

Apache Solr for Indexing Data

Overview of this book

Apache Solr is a widely used, open source enterprise search server that delivers powerful indexing and searching features. These features help fetch relevant information from various sources and documentation. Solr also combines with other open source tools such as Apache Tika and Apache Nutch to provide more powerful features. This fast-paced guide starts by helping you set up Solr and get acquainted with its basic building blocks, to give you a better understanding of Solr indexing. You’ll quickly move on to indexing text and boosting the indexing time. Next, you’ll focus on basic indexing techniques, various index handlers designed to modify documents, and indexing a structured data source through Data Import Handler. Moving on, you will learn techniques to perform real-time indexing and atomic updates, as well as more advanced indexing techniques such as de-duplication. Later on, we’ll help you set up a cluster of Solr servers that combine fault tolerance and high availability. You will also gain insights into working scenarios of different aspects of Solr and how to use Solr with e-commerce data. By the end of the book, you will be competent and confident working with indexing and will have a good knowledge base to efficiently program elements.
Table of Contents (18 chapters)
Apache Solr for Indexing Data
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Filters


Like tokenizers, filters consume tokens as input and again produce a stream of tokens. The function of a filter is a bit different from that of a tokenizer. Unlike a tokenizer, a filter receives tokens as the input (passed by a tokenizer), and its function is to look at each token and decide whether to keep this token, change/replace it, or discard it. Filters are also derive from org.apache.lucene.analysis.TokenStream.

A typical example of a filter looks something like this:

<fieldType name="text" class="solr.TextField">
  <analyzer>
    <tokenizer class="solr.StandardTokenizerFactory"/>
    <filter class="solr.StandardFilterFactory"/>
    <filter class="solr.LowerCaseFilterFactory"/>
</analyzer>
</fieldType>

Filters are configured in schema.xml with a <filter> element as a child of <analyzer>, following the <tokenizer> element. Since filters take token streams as input, the filter definition should follow the tokenizer or...