Question

I have a huge array list which contains 1000 entries out of which one of the entry is “world”. And, I have a word “big world”. I want to get the word “big world” matched with “world” in the arraylist.

What is the most cost effective way of doing it? I cannot use .contains method of array list, and If I traverse all the 1000 entries and match them by pattern its going to be very costly in terms of performance. I am using Java for this.

Could you please let me know what is the best way for this?

Cheers,
J

Answer 1

You can split up every single element of the ArrayList into words and stop as soon as you find one of them.

I suppose by your profile you develop in Java, with Lucene you would easily do something like that

public class NodesAnalyzer extends Analyzer {   
    public TokenStream tokenStream(String fieldName, Reader reader) {

        Tokenizer tokenizer = new StandardTokenizer(reader)
        TokenFilter lowerCaseFilter = new LowerCaseFilter(tokenizer)
        TokenFilter stopFilter = new StopFilter(lowerCaseFilter, Data.stopWords.collect{ it.text } as String[])
        SnowballFilter snowballFilter = new SnowballFilter(stopFilter, new org.tartarus.snowball.ext.ItalianStemmer())

        return snowballFilter
    }   
}

    Analyzer analyzer = new NodesAnalyzer()

    TokenStream ts = analyzer.tokenStream(null, new StringReader(str)); 
    Token token = ts.next()

    while (token != null) {
       String cur = token.term()
       token = ts.next();
    }

Note: this is Groovy code that I copied from a personal project so you will have to translate things like Data.stopWords.collect{ it.text } as String[] to use with plain Java