ParseHelper.java

package dbfit.util;

import fit.Fixture;
import fit.TypeAdapter;

import static dbfit.util.SymbolUtil.isSymbolGetter;

/* this class addresses several issues with parsing, and is used as a base for any other dbfit type adapters:
 * 1: TypeAdapter does not check the parse delegates directly when parsing, it relies on appropriate delegate
 *    being selected when adapter is created; this creates problems for dbfit adapters which need to delegate parsing
 *    to appropriate types, but access values from sql parameters etc
 * 2: this class encapsulates symbol access using <<
 * 3: some db drivers will return different numeric types for the same column depending on use (in view, autogenerated..);
 *    this adapter tries to fix inconsistent types first by casting, then by parsing if needed
 *
 */

public class ParseHelper {
    private Class<?> type;
    private Fixture fixture;

    public ParseHelper(Fixture fixture, Class<?> type) {
        this.type = type;
        this.fixture = fixture;
    }

    private Object tryToConvert(Object value) throws Exception {
        try {
            return type.cast(value);
        } catch (ClassCastException cex) {
            return parse(value.toString());
        }
    }

    private Object parseSymbol(String s) throws Exception {
        Object value = dbfit.util.SymbolUtil.getSymbol(s);
        if (null == value || value.getClass().equals(type)) {
            return value;
        }

        // else try to convert
        try {
            return tryToConvert(value);
        } catch (Exception e) {
            throw new UnsupportedOperationException(
                "Incompatible types between symbol and cell value: expected " +
                type + "; but symbol is " + value.getClass(), e);
        }
    }

    public Object parse(String s) throws Exception {
        if (isSymbolGetter(s)) {
            return parseSymbol(s);
        }

        String trim = s.trim();

        if (trim.toLowerCase().equals("null")) {
            return null;
        }

        if (type.equals(String.class) && Options.isFixedLengthStringParsing() &&
                trim.startsWith("'") && trim.endsWith("'")) {
            return trim.substring(1, trim.length() - 1);
        }

        TypeAdapter ta = TypeAdapter.adapterFor(type);
        ta.init(fixture, type);

        return ta.parse(s);
    }
}