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  1. import java.util.*;
  2. import java.io.*;
  3. import java.util.stream.*;
  4.  
  5. class Main
  6. {
  7. 	public static void main(String[] args) throws IOException {
  8.         final List<Filter> list = Arrays.asList(new Filter("status", "equal", "active"),
  9.                 new Filter("status", "equal", "inactive"), new Filter("name", "equal", "jhon"),
  10.                 new Filter("id", "equal", 123));
  11.         final Map<String, List<Filter>> map = list.stream()
  12.                 .collect(Collectors.groupingBy(Filter::getKey, LinkedHashMap::new, Collectors.toList()));
  13.         final List<Filter> result = map.entrySet().stream()
  14.                 .map(e -> e.getValue().size() > 1
  15.                         ? new Filter(e.getKey(), "in", e.getValue().stream().map(Filter::getValue).toArray())
  16.                         : e.getValue().get(0))
  17.                 .collect(Collectors.toList());
  18.         result.forEach(System.out::println);
  19.     }
  20. }
  21.  
  22. class Filter {
  23.     private String key;
  24.     private String operator;
  25.     private Object value;
  26.  
  27.     public Filter(String key, String operator, Object value) {
  28.         super();
  29.         this.key = key;
  30.         this.operator = operator;
  31.         this.value = value;
  32.     }
  33.  
  34.     public String getKey() {
  35.         return key;
  36.     }
  37.  
  38.     public String getOperator() {
  39.         return operator;
  40.     }
  41.  
  42.     public Object getValue() {
  43.         return value;
  44.     }
  45.  
  46.     @Override
  47.     public String toString() {
  48.         StringBuilder builder = new StringBuilder();
  49.         builder.append("Filter [key=").append(key).append(", operator=").append(operator).append(", value=")
  50.                 .append(value != null && value.getClass().isArray() ? Arrays.deepToString((Object[])value) : value)
  51.                 .append("]");
  52.         return builder.toString();
  53.     }
  54. }
Success #stdin #stdout 0.08s 34492KB
comments (?)
stdin 
Standard input is empty
stdout 
Filter [key=status, operator=in, value=[active, inactive]]
Filter [key=name, operator=equal, value=jhon]
Filter [key=id, operator=equal, value=123]
https://ideone.com/em5lAF
language:
Java (HotSpot 12)
created:
5 years ago
visibility:
public

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