com.avaje.ebean.DRawSqlColumnsParser Maven / Gradle / Ivy

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package com.avaje.ebean;

import java.util.ArrayList;
import java.util.Arrays;

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 columns = new ArrayList();
		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 tmp = new ArrayList(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 == 1){
		    return new ColumnMapping.Column(indexPos++, split[0], null);
		}
		if (split.length == 2){
            return new ColumnMapping.Column(indexPos++, split[0], split[1]);
        }
        if (split.length == 3){
            if (!split[1].equalsIgnoreCase("as")){
                String msg = "Expecting AS keyword parsing column "+colInfo;
                throw new PersistenceException(msg);
            }
            return new ColumnMapping.Column(indexPos++, split[0], split[2]);
        }
		
        String msg = "Expecting Max 3 words parsing column "+colInfo+". Got "+Arrays.toString(split);
        throw new PersistenceException(msg);		
	}


	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;
	}
}