What is the best way to filter a Java Collection?

Question

I want to filter a java.util.Collection based on a predicate.

Answer 1

With the ForEach DSL you may write

import static ch.akuhn.util.query.Query.select;
import static ch.akuhn.util.query.Query.$result;
import ch.akuhn.util.query.Select;

Collection collection = ...

for (Select each : select(collection)) {
    each.yield = each.value.length() > 3;
}

Collection result = $result();

Given a collection of [The, quick, brown, fox, jumps, over, the, lazy, dog] this results in [quick, brown, jumps, over, lazy], ie all strings longer than three characters.

All iteration styles supported by the ForEach DSL are

• AllSatisfy
• AnySatisfy
• Collect
• Counnt
• CutPieces
• Detect
• GroupedBy
• IndexOf
• InjectInto
• Reject
• Select

For more details, please refer to https://www.iam.unibe.ch/scg/svn_repos/Sources/ForEach