Combine multiple lists into a single comma-separated list

Summary

The join macro combines one or more lists into a single comma-separated list. It flattens all input lists and returns them joined with commas.

Syntax 

${join;<list>[;<list>...]}

Parameters

  • list - One or more lists to combine (items within lists can be comma or semicolon-separated)

Behavior

  • Splits each input list into individual elements
  • Combines all elements from all lists
  • Returns a single comma-separated list
  • Preserves the order of elements
  • Removes empty elements

Examples

Join two lists:

${join;apple,banana;cherry,date}
# Returns: "apple,banana,cherry,date"

Join multiple lists:

${join;red,green;blue;yellow,orange}
# Returns: "red,green,blue,yellow,orange"

Flatten nested lists:

list1=a,b,c
list2=d,e,f
${join;${list1};${list2}}
# Returns: "a,b,c,d,e,f"

Combine with other macros:

${join;${exports};${imports}}
# Returns all exported and imported packages

Use Cases

  • Combining multiple configuration lists
  • Merging classpath or dependency lists
  • Concatenating package lists
  • Building composite values from multiple sources
  • Flattening nested list structures
  • Creating unified collections

Notes

  • Input lists can use comma or semicolon separators
  • Output is always comma-separated
  • Empty elements are filtered out
  • Element order is preserved
  • No deduplication - duplicate elements are kept
  • To join with a custom separator (not comma), use ${sjoin;<separator>;<list>...} instead
  • See also: ${uniq} for removing duplicates
  • See also: ${sjoin} for custom separator joining

See test cases in MacroTestsForDocsExamples.java