package com.avaje.ebean;
import java.util.ArrayList;
import javax.persistence.PersistenceException;
import com.avaje.ebean.RawSql.ColumnMapping;
/**
* Parses columnMapping (select clause) mapping columns to bean properties.
*/
final class DRawSqlColumnsParser {
private final int end;
private final String sqlSelect;
private int pos;
private int indexPos;
public static ColumnMapping parse(String sqlSelect) {
return new DRawSqlColumnsParser(sqlSelect).parse();
}
private DRawSqlColumnsParser(String sqlSelect) {
this.sqlSelect = sqlSelect;
this.end = sqlSelect.length();
}
private ColumnMapping parse() {
ArrayList<ColumnMapping.Column> columns = new ArrayList<ColumnMapping.Column>();
while (pos <= end) {
ColumnMapping.Column c = nextColumnInfo();
columns.add(c);
}
return new ColumnMapping(columns);
}
private ColumnMapping.Column nextColumnInfo() {
int start = pos;
nextComma();
String colInfo = sqlSelect.substring(start, pos++);
colInfo = colInfo.trim();
String[] split = colInfo.split(" ");
if (split.length > 1) {
ArrayList<String> tmp = new ArrayList<String>(split.length);
for (int i = 0; i < split.length; i++) {
if (split[i].trim().length() > 0) {
tmp.add(split[i].trim());
}
}
split = tmp.toArray(new String[tmp.size()]);
}
if (split.length == 0) {
throw new PersistenceException("Huh? Not expecting length=0 when parsing column " + colInfo);
}
if (split.length == 1) {
// default to column the same name as the property
return new ColumnMapping.Column(indexPos++, split[0], null);
}
if (split.length == 2) {
return new ColumnMapping.Column(indexPos++, split[0], split[1]);
}
// Ok, we now expect/require the AS keyword and it should be the
// second to last word in the colInfo content
if (!split[split.length - 2].equalsIgnoreCase("as")) {
throw new PersistenceException("Expecting AS keyword as second to last word when parsing column " + colInfo);
}
// build back the 'column formula' that precedes the AS keyword
StringBuilder sb = new StringBuilder();
sb.append(split[0]);
for (int i = 1; i < split.length-2; i++) {
sb.append(" ").append(split[i]);
}
return new ColumnMapping.Column(indexPos++, sb.toString(), split[split.length - 1]);
}
private int nextComma() {
boolean inQuote = false;
while (pos < end) {
char c = sqlSelect.charAt(pos);
if (c == '\'') {
inQuote = !inQuote;
} else if (!inQuote && c == ',') {
return pos;
}
pos++;
}
return pos;
}
}