package com.avaje.ebeaninternal.util;
import com.avaje.ebeaninternal.util.SortByClause.Property;
public final class SortByClauseParser {
private final String rawSortBy;
public static SortByClause parse(String rawSortByClause){
return new SortByClauseParser(rawSortByClause).parse();
}
private SortByClauseParser(String rawSortByClause) {
this.rawSortBy = rawSortByClause.trim();
}
private SortByClause parse(){
SortByClause sortBy = new SortByClause();
String[] sections = rawSortBy.split(",");
for (int i = 0; i < sections.length; i++) {
Property p = parseSection(sections[i].trim());
if (p == null){
break;
} else {
sortBy.add(p);
}
}
return sortBy;
}
private Property parseSection(String section){
if (section.length() == 0){
return null;
}
String[] words = section.split(" ");
if (words.length < 1 || words.length > 3){
throw new RuntimeException("Expecting 1 to 3 words in ["+section+"] but got ["+words.length+"]");
}
Boolean nullsHigh = null;
boolean ascending = true;
String propName = words[0];
if (words.length > 1){
if (words[1].startsWith("nulls")){
nullsHigh = isNullsHigh(words[1]);
} else {
ascending = isAscending(words[1]);
}
}
if (words.length > 2){
if (words[2].startsWith("nulls")){
nullsHigh = isNullsHigh(words[2]);
} else {
ascending = isAscending(words[2]);
}
}
return new Property(propName, ascending, nullsHigh);
}
private Boolean isNullsHigh(String word){
if (SortByClause.NULLSHIGH.equalsIgnoreCase(word)){
return Boolean.TRUE;
}
if (SortByClause.NULLSLOW.equalsIgnoreCase(word)){
return Boolean.FALSE;
}
String m = "Expecting nullsHigh or nullsLow but got ["+word+"] in ["+rawSortBy+"]";
throw new RuntimeException(m);
}
private boolean isAscending(String word){
if (SortByClause.ASC.equalsIgnoreCase(word)){
return true;
}
if (SortByClause.DESC.equalsIgnoreCase(word)){
return false;
}
String m = "Expection ASC or DESC but got ["+word+"] in ["+rawSortBy+"]";
throw new RuntimeException(m);
}
}