Book Image

Mastering Apache Solr 7.x

By : Sandeep Nair, Chintan Mehta, Dharmesh Vasoya
Book Image

Mastering Apache Solr 7.x

By: Sandeep Nair, Chintan Mehta, Dharmesh Vasoya

Overview of this book

Apache Solr is the only standalone enterprise search server with a REST-like application interface. providing highly scalable, distributed search and index replication for many of the world's largest internet sites. To begin with, you would be introduced to how you perform full text search, multiple filter search, perform dynamic clustering and so on helping you to brush up the basics of Apache Solr. You will also explore the new features and advanced options released in Apache Solr 7.x which will get you numerous performance aspects and making data investigation simpler, easier and powerful. You will learn to build complex queries, extensive filters and how are they compiled in your system to bring relevance in your search tools. You will learn to carry out Solr scoring, elements affecting the document score and how you can optimize or tune the score for the application at hand. You will learn to extract features of documents, writing complex queries in re-ranking the documents. You will also learn advanced options helping you to know what content is indexed and how the extracted content is indexed. Throughout the book, you would go through complex problems with solutions along with varied approaches to tackle your business needs. By the end of this book, you will gain advanced proficiency to build out-of-box smart search solutions for your enterprise demands.
Table of Contents (14 chapters)
Title Page
Packt Upsell
Contributors
Preface
Index

Understanding filters


We have seen that the analyzer uses a series of tokenizer and filter classes together to transform the input string into a token string, which will be used by Solr in indexing. The job of the filter is different from the tokenizer. The tokenizer mostly splits the input string at some delimiters and generates a token stream. The filter transforms this stream into some other form and generates a new token stream. The input for a filter will be a token stream, not an input string, unlike what we were passing at the time of tokenization. The entire token stream generated through tokenization will be passed to the first filter class in the list. Let's cover filters in detail.

What is a filter?

A filter is a tool provided by Solr that runs a filtering process as follows:

  • Adding: Adds a new token to the stream, such as adding synonyms
  • Removing: Removes a token from the stream, such as stop words
  • Conversation: Converts a token from one form to another form, say uppercase to lower...