Join a Collection on any POJO with a Data Extractor

CallingMyCollectionsUtil.java

com.bmchild;

//imports

public class CallingMyCollectionsUtil {

	private class Pojo {
		private String field;
		
		public String getField() {
		return field;
		}
		
		public String setField(String field) {
			this.field = field;
		}
	}

    public void main(Sring[] args) {
		
		Pojo pojo1 = new Pojo();
		pojo1.setField("AWS");
		Pojo pojo2 = new Pojo();
		pojo2.setField("SOME");
		List<Pojo> pojos = new ArrayList<Pojo>();
		pojos.add(pojo1);
		pojos.add(pojo2);
		
		String emailString = MyCollectionsUtil.join(pojos, "->", new DataExtractor<Pojo>() {
			public String val(Pojo obj) {return obj.getField;	}
		});

    }

}

MyCollectionsUtil.java

com.bmchild.util;

public class MyCollectionsUtil {

      public static <T> String join(List<T> objs, String delimiter, MyDataExtractor<T> dataExtractor) {
		
		StringBuilder string = new StringBuilder();
		if(!CollectionUtils.isEmpty(objs)) {
			
			int i = 0;
			int size = objs.size();
			for (T obj : objs) {
				string.append(dataExtractor.val(obj));
				if(i < size -1) {
					string.append(delimiter);
				}
				i++;
			}
			
		}
		
		return string.toString();
	}

}

MyDataExtracter.java

com.bmchild.extractor;

public interface MyDataExtractor<T> {
	
	/**
	 * Extracts the desired value from the given object.
	 * 
	 * @param obj The object.
	 * @return The desired value extracted from the object.
	 */
	String val(T obj);
}