Simple vs. Easy: Writing A Generic Code To Avoid Duplication - replacing a number of anemic data structures with a generic one - BEFORE See http://wondersofcode.wordpress.com/2013/05/04/simple-vs-easy…id-duplication/

LogEntry.java

public interface LogEntry {
     Date getTimestamp();
     /** For dumping into a .tsv file to be imported into Hadoop */
     String toTabDelimitedString();
     String getSearchTerms();
     boolean hasSearchTerms();
     String[][] getColumns();
     String getKey();
     void mergeWith(LogEntry entry);
}

PlayerEventLogEntry.java

// Another impl. of LogEntry, to showcase the conceptual and, 
// to a degree, factual duplication
public class PlayerEventLogEntry implements LogEntry {
    
    public static final String[][] COLUMNS = { ... }
    
    private String userId;
    private String contentId;
    private String sessionId;
    ...
    
    public PlayerEventLogEntry(...) { /* assign all fields ... */ }

    @Override
    public String[][] getColumns() {
	return COLUMNS;
    }
    ...
        
	@Override
	public String toTabDelimitedString() {
		StringBuilder sb=new StringBuilder();
		sb.append(contentId);
		sb.append(FIELD_DELIMITER);
		sb.append(userId);
		sb.append(FIELD_DELIMITER);
		sb.append(sessionId);
		sb.append(FIELD_DELIMITER);
		...
		return sb.toString();
	}
}

PlayerEventsParser.java

// Called from a data import job to process individual log lines.
// Some time later, the job will call toTabDelimitedString on it.
public class PlayerEventsParser ... {

   @Override
    public LogEntry parse(String logLine) throws LogParseException {
        ... // tokenizing, processing etc. of the data ...
        return new PlayerEventLogEntry(userId, contentId, sessionId, ...);
    }
    
}

RightGrantedLogEntry.java

// One of 15 implementations of LogEntry for import of right granted event logs
public class RightGrantedLogEntry implements LogEntry {

	private static final char FIELD_DELIMITER = '\t';
        
    public static final String[][] COLUMNS = { { "messageId", "STRING" }
		{ "userId", "STRING" },{ "rightId", "STRING" }, ... };


	private String messageId;
	private Date timestamp;
	private String userId;
	private String rightId;
	...

	public RightGrantedLogEntry(String messageId, Date timestamp, String userId, String rightId, ...) {
		this.messageId=messageId;
		this.timestamp=timestamp;
		this.userId=userId;
		this.rightId=rightId;
		...
	}

	@Override
	public String[][] getColumns() {
		return RightGrantedLogEntry.COLUMNS;
	}

	@Override
	public String getKey() {
		return messageId;
	}

	@Override
	public String getSearchTerms() {
		return null;
	}

	@Override
	public Date getTimestamp() {
		return timestamp;
	}

	@Override
	public boolean hasSearchTerms() {
		return false;
	}

	@Override
	public void mergeWith(LogEntry arg0) {}  
	
	@Override
	public String toTabDelimitedString() {
		StringBuilder sb=new StringBuilder();
		sb.append(messageId);
		sb.append(FIELD_DELIMITER);
		sb.append(userId);
		sb.append(FIELD_DELIMITER);
		sb.append(rightId);
		sb.append(FIELD_DELIMITER);
		...
		return sb.toString();
	}
}