sfussenegger

package at.molindo.util.hibernate;

import java.io.Serializable;
import java.lang.reflect.Method;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

import org.hibernate.HibernateException;
import org.hibernate.type.NullableType;
import org.hibernate.type.TypeFactory;
import org.hibernate.usertype.ParameterizedType;
import org.hibernate.usertype.UserType;

public class EnumUserType implements UserType, ParameterizedType {
    private static final String DEFAULT_IDENTIFIER_METHOD_NAME = "name";
    private static final String DEFAULT_VALUE_OF_METHOD_NAME = "valueOf";

    protected static final String IDENTIFIER_METHOD = "identifierMethod";
    protected static final String VALUEOF_METHOD = "valueOfMethod";

    @SuppressWarnings("unchecked")
    private Class<? extends Enum> enumClass;
    private Class<?> identifierType;
    private Method identifierMethod;
    private Method valueOfMethod;
    private NullableType type;
    private int[] sqlTypes;

    public void setParameterValues(final Properties parameters) {
        final String enumClassName = parameters.getProperty("enumClass");
        try {
            enumClass = Class.forName(enumClassName).asSubclass(Enum.class);
        } catch (final ClassNotFoundException cfne) {
            throw new HibernateException("Enum class not found", cfne);
        }

        final String identifierMethodName = parameters
                .getProperty(IDENTIFIER_METHOD, DEFAULT_IDENTIFIER_METHOD_NAME);

        try {
            identifierMethod = enumClass.getMethod(identifierMethodName, new Class[0]);
            identifierType = identifierMethod.getReturnType();
        } catch (final Exception e) {
            throw new HibernateException("Failed to obtain identifier method", e);
        }

        type = (NullableType) TypeFactory.basic(identifierType.getName());

        if (type == null) {
            throw new HibernateException("Unsupported identifier type " + identifierType.getName());
        }

        sqlTypes = new int[] { type.sqlType() };

        final String valueOfMethodName = parameters
                .getProperty(VALUEOF_METHOD, DEFAULT_VALUE_OF_METHOD_NAME);

        try {
            valueOfMethod = enumClass.getMethod(valueOfMethodName, new Class[] { identifierType });
        } catch (final Exception e) {
            throw new HibernateException("Failed to obtain valueOf method", e);
        }
    }

    public Class<?> returnedClass() {
        return enumClass;
    }

    public Object nullSafeGet(final ResultSet rs, final String[] names, final Object owner) throws HibernateException, SQLException {
        final Object identifier = type.get(rs, names[0]);
        if (rs.wasNull()) {
            return null;
        }

        try {
            return valueOfMethod.invoke(enumClass, new Object[] { identifier });
        } catch (final Exception e) {
            throw new HibernateException("Exception while invoking valueOf method '"
                    + valueOfMethod.getName() + "' of " + "enumeration class '" + enumClass + "'", e);
        }
    }

    public void nullSafeSet(final PreparedStatement st, final Object value, final int index) throws HibernateException, SQLException {
        try {
            if (value == null) {
                st.setNull(index, type.sqlType());
            } else {
                final Object identifier = identifierMethod.invoke(value, new Object[0]);
                type.set(st, identifier, index);
            }
        } catch (final Exception e) {
            throw new HibernateException("Exception while invoking identifierMethod '"
                    + identifierMethod.getName() + "' of " + "enumeration class '" + enumClass
                    + "'", e);
        }
    }

    public int[] sqlTypes() {
        return sqlTypes;
    }

    public Object assemble(final Serializable cached, final Object owner) throws HibernateException {
        return cached;
    }

    public Object deepCopy(final Object value) throws HibernateException {
        return value;
    }

    public Serializable disassemble(final Object value) throws HibernateException {
        return (Serializable) value;
    }

    public boolean equals(final Object x, final Object y) throws HibernateException {
        return x == y;
    }

    public int hashCode(final Object x) throws HibernateException {
        return x.hashCode();
    }

    public boolean isMutable() {
        return false;
    }

    public Object replace(final Object original, final Object target, final Object owner) throws HibernateException {
        return original;
    }
}