Question: I would like to index some words with special characters all together. 

For example, given `m&m`, I would like to index it as a whole, rather than delimiting it as `m` and `m` (normally `&` would be considered as a delimiter). 

Is there a way to achieve this by using standard tokenizer/filter or should I have to write one myself?

Answer: 
basically text field type filter out special characters before indexing. and you can use string type but it is not advisable for searching on it. you can use **types option** of **WordDelimiterFilterFactory** and you can convert those special characters to alphabetical

% => percent
& => and
you can use WhiteSpaceTokenizerFactory.

<http://docs.lucidworks.com/display/solr/Tokenizers#Tokenizers-WhiteSpaceTokenizer>

It will tokenize only on whitespaces. For example,

"m&m" will be considered as a single token and so it would indexed like that