something like that
public final class PgPersonByEmail implements People {
private final DataSource dataSource;
private final People source;
private final Email email;
public PgPersonByEmail(DataSource dataSource, Email email) {
this(
dataSource,
new PgPeople(dataSource),
email
);
}
public PgPersonByEmail(DataSource dataSource, People source, Email email) {
this.dataSource = dataSource;
this.source = source;
this.email = email;
}
public Person first() {
return iterate().iterator().next();
}
@Override
public Iterable<Person> iterate() {
try {
return new JdbcSession(this.dataSource)
.sql("SELECT id FROM person where email = ?")
.set(email.toString()).select(
new ListOutcome<>(
(ListOutcome.Mapping<Person>) rset -> new PgPerson(
dataSource,
rset.getInt(1)
)
)
);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public Person add(Email email) {
return this.source.add(email);
}
}
You are doing all of the work all over again in this decorator.
First, you need a target or origin result set representing the list of people that is unfiltered. This is the only object that will EVER touch the database. So is that what you are trying to show here, and then you will decorate?
Maybe I didnt know how to read this actually...
rather than getting the entire list of people.
yes?
this is the original implementation
public final class PgPeople implements People {
private final DataSource dataSource;
public PgPeople(DataSource dataSource) {
this.dataSource = dataSource;
}
@Override
public Iterable<Person> iterate() {
try {
return new JdbcSession(this.dataSource)
.sql("SELECT id FROM person")
.select(
new ListOutcome<>(
(ListOutcome.Mapping<Person>) rset -> new PgPerson(
dataSource,
rset.getInt(1)
)
)
);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public Person add(Email email) {
try {
return new PgPerson(
this.dataSource,
new JdbcSession(dataSource)
.sql("INSERT INTO person (email) VALUES (?)")
.set(email.toString())
.update(new SingleOutcome<>(Long.class)).intValue()
);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
}
A list of people is all people who fit some criteria. By definition if no criteria are specified then that means the entire set.
A filtered list of people is a list of people, who, having all people who fit a criteria, only returns you some subset that matches an additional criteria. That is why he is a decorator.
You cant mix and match the ideas like I think you are doing.
ok now I see
You cant try to inject some kind of new sql to make the inner list act differently from what he was doing before.
That would be a procedural idea.
something like that
public final class PgOrganizations implements Organizations {
private final DataSource dataSource;
private final Filter filteredBy;
private final Object[] params;
public PgOrganizations(DataSource dataSource) {
this(
dataSource,
Filter.NONE
);
}
public PgOrganizations(DataSource dataSource, Filter filteredBy, Object... params) {
this.dataSource = dataSource;
this.filteredBy = filteredBy;
this.params = params;
}
@Override
public Iterable<Organization> iterate() {
try {
final JdbcSession session = new JdbcSession(this.dataSource);
session.sql(
String.format("SELECT id FROM organization %s", filteredBy.where)
);
for (Object param : params) {
session.set(param);
}
return session.select(
new ListOutcome<>(
(ListOutcome.Mapping<Organization>) rset -> new PgOrganization(
dataSource,
rset.getInt(1)
)
)
);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public Organization add(OrganizationUrl url) {
try {
return new PgOrganization(
this.dataSource,
new JdbcSession(dataSource)
.sql("INSERT INTO organization (email) VALUES (?)")
.set(url.toString())
.update(new SingleOutcome<>(Long.class)).intValue()
);
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
public enum Filter {
NONE(""),
BY_URL("where url = ?");
private final String where;
Filter(String where) {
this.where = where;
}
}
}
you are creating a super object that is god-controlling all of the needed behavior in this problem.
think about modelling
What is going on here that we are MODELLING?
the problem that I'm trying to solve is sometimes I need to find a person by email but the identity of the person is an int id like that
@EqualsAndHashCode(of = "id")
public final class PgPerson implements Person {
private static final Logger LOGGER = LoggerFactory.getLogger(PgPerson.class);
private final DataSource dataSource;
private final int id;
private final Account account;
public PgPerson(DataSource dataSource, int id) {
this(
dataSource,
id,
new PgAccount(
dataSource,
id
)
);
}
public PgPerson(DataSource dataSource, int id, Account account) {
this.dataSource = dataSource;
this.id = id;
this.account = account;
}
@Override
public int id() {
return this.id;
}
@Override
public void update(Name name) {
LOGGER.debug(
"name: {}",
name.toString());
try {
new JdbcSession(this.dataSource)
.sql("update person set first=?, middle=?, last=? where id = ?")
.set(name.first())
.set(name.middle())
.set(name.last())
.set(this.id)
.execute();
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public Name name() {
try {
return new JdbcSession(this.dataSource)
.sql("select COALESCE(first,''), COALESCE(middle,''), COALESCE(last,'') from person where id = ?")
.set(this.id)
.select((Outcome<Name>) (rset, stmt) -> {
rset.next();
return new DefaultName(
rset.getString(1),
rset.getString(2),
rset.getString(3)
);
});
} catch (SQLException e) {
throw new RuntimeException(e);
}
}
@Override
public Account account() {
return this.account;
}
}
Could be by organization.
The list of attributes is pretty large.
but I really don't know how fit the requirement to filter by last name (for example) without do what I made in the people class to filter by last name without rewrite the iterate method or use filter like the organizations
whats the difference? None.
The fact that the email is a unique mapping to a person is irrelevant.
See, if you are looking for a person you have to stick with the person object.
But if you are looking for potentially more than you just need a list that sorts on any criteria you specify.
You need to strip them down and repackage the code.
that isn't right.
First of all. The list of people is a thing that we are modelling. Right? So it has a coordinate to a real world target (the database), which as all of the needed information about this list.