import static com.google.common.base.Optional.of;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Optional.of;
import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkNotNull;
import static java.lang.Math.max;
import static java.lang.Math.min;
import static java.util.UUID.randomUUID;
import static java.lang.Math.max;
import static java.lang.Math.min;
import static java.util.UUID.randomUUID;
public Field addField(String fieldName) throws IllegalArgumentException {
checkNotNull(fieldName, "fieldName must not be null");
checkArgument(fieldName.length() > 0, "fieldName must not be empty");
public Field addField(String fieldName) throws IllegalArgumentException {
checkNotNull(fieldName, "fieldName must not be null");
checkArgument(fieldName.length() > 0, "fieldName must not be empty");