/**
* Selects all entities of the specified type which match the given <code>Query</code>. This
* method creates a <code>PreparedStatement</code> using the <code>Query</code> instance specified
* against the table represented by the given type. This query is then executed (with the
* parameters specified in the query). The method then iterates through the result set and
* extracts the specified field, mapping an entity of the given type to each row. This array of
* entities is returned.
*
* @param type The type of the entities to retrieve.
* @param field The field value to use in the creation of the entities. This is usually the
* primary key field of the corresponding table.
* @param query The {@link Query} instance to use in determining the results.
* @return An array of entities of the given type which match the specified query.
*/
public <T extends RawEntity<K>, K> T[] find(Class<T> type, String field, Query query)
throws SQLException {
List<T> back = new ArrayList<T>();
query.resolveFields(type, getFieldNameConverter());
// <ian>
Version version = type.getAnnotation(Version.class);
if (version != null && !version.findInitial()) {
// Add initial version check to exclude
// objects that have only been created and not saved yet.
if (query.getWhereClause() == null) {
query.where(version.value() + " != ?", version.initial());
} else {
// Preserve existing WHERE clause and parameters
String whereClause =
new StringBuilder()
.append(query.getWhereClause())
.append(" AND ")
.append(version.value())
.append(" != ?")
.toString();
Object[] paramsOld = query.getWhereParams();
Object[] paramsNew = new Object[paramsOld.length + 1];
System.arraycopy(paramsOld, 0, paramsNew, 0, paramsOld.length);
paramsNew[paramsNew.length - 1] = version.initial();
query.setWhereClause(whereClause);
query.setWhereParams(paramsNew);
}
}
// </ian>
Preload preloadAnnotation = type.getAnnotation(Preload.class);
if (preloadAnnotation != null) {
if (!query.getFields()[0].equals("*") && query.getJoins().isEmpty()) {
String[] oldFields = query.getFields();
List<String> newFields = new ArrayList<String>();
for (String newField : preloadAnnotation.value()) {
newField = newField.trim();
int fieldLoc = -1;
for (int i = 0; i < oldFields.length; i++) {
if (oldFields[i].equals(newField)) {
fieldLoc = i;
break;
}
}
if (fieldLoc < 0) {
newFields.add(newField);
} else {
newFields.add(oldFields[fieldLoc]);
}
}
if (!newFields.contains("*")) {
for (String oldField : oldFields) {
if (!newFields.contains(oldField)) {
newFields.add(oldField);
}
}
}
query.setFields(newFields.toArray(new String[newFields.size()]));
}
}
Connection conn = getProvider().getConnection();
try {
String sql = null;
tableNameConverterLock.readLock().lock();
try {
sql = query.toSQL(type, provider, tableNameConverter, getFieldNameConverter(), false);
} finally {
tableNameConverterLock.readLock().unlock();
}
Logger.getLogger("net.java.ao").log(Level.INFO, sql);
PreparedStatement stmt =
conn.prepareStatement(sql, ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_READ_ONLY);
provider.setQueryStatementProperties(stmt, query);
query.setParameters(this, stmt);
ResultSet res = stmt.executeQuery();
provider.setQueryResultSetProperties(res, query);
while (res.next()) {
T entity =
peer(
type,
Common.getPrimaryKeyType(type)
.pullFromDatabase(this, res, Common.getPrimaryKeyClassType(type), field));
CacheLayer cacheLayer = getProxyForEntity(entity).getCacheLayer(entity);
for (String cacheField : query.getCanonicalFields(type, fieldNameConverter)) {
cacheLayer.put(cacheField, res.getObject(cacheField));
}
back.add(entity);
}
res.close();
stmt.close();
} finally {
conn.close();
}
return back.toArray((T[]) Array.newInstance(type, back.size()));
}
/**
* Creates a new entity of the specified type with the optionally specified initial parameters.
* This method actually inserts a row into the table represented by the entity type and returns
* the entity instance which corresponds to that row.
*
* <p>The {@link DBParam} object parameters are designed to allow the creation of entities which
* have non-null fields which have no defalut or auto-generated value. Insertion of a row without
* such field values would of course fail, thus the need for db params. The db params can also be
* used to set the values for any field in the row, leading to more compact code under certain
* circumstances.
*
* <p>Unless within a transaction, this method will commit to the database immediately and exactly
* once per call. Thus, care should be taken in the creation of large numbers of entities. There
* doesn't seem to be a more efficient way to create large numbers of entities, however one should
* still be aware of the performance implications.
*
* <p>This method delegates the action INSERT action to {@link
* DatabaseProvider#insertReturningKey(EntityManager, Connection, Class, String, boolean, String,
* DBParam...)}. This is necessary because not all databases support the JDBC <code>
* RETURN_GENERATED_KEYS</code> constant (e.g. PostgreSQL and HSQLDB). Thus, the database provider
* itself is responsible for handling INSERTion and retrieval of the correct primary key value.
*
* @param type The type of the entity to INSERT.
* @param params An optional varargs array of initial values for the fields in the row. These
* values will be passed to the database within the INSERT statement.
* @return The new entity instance corresponding to the INSERTed row.
* @see net.java.ao.DBParam
* @see net.java.ao.DatabaseProvider#insertReturningKey(EntityManager, Connection, Class, String,
* boolean, String, DBParam...)
*/
public <T extends RawEntity<K>, K> T create(Class<T> type, DBParam... params)
throws SQLException {
T back = null;
String table = null;
tableNameConverterLock.readLock().lock();
try {
table = tableNameConverter.getName(type);
} finally {
tableNameConverterLock.readLock().unlock();
}
Set<DBParam> listParams = new HashSet<DBParam>();
listParams.addAll(Arrays.asList(params));
fieldNameConverterLock.readLock().lock();
try {
for (Method method : MethodFinder.getInstance().findAnnotation(Generator.class, type)) {
Generator genAnno = method.getAnnotation(Generator.class);
String field = fieldNameConverter.getName(method);
ValueGenerator<?> generator;
valGenCacheLock.writeLock().lock();
try {
if (valGenCache.containsKey(genAnno.value())) {
generator = valGenCache.get(genAnno.value());
} else {
generator = genAnno.value().newInstance();
valGenCache.put(genAnno.value(), generator);
}
} catch (InstantiationException e) {
continue;
} catch (IllegalAccessException e) {
continue;
} finally {
valGenCacheLock.writeLock().unlock();
}
listParams.add(new DBParam(field, generator.generateValue(this)));
}
// <ian>
Version version = type.getAnnotation(Version.class);
if (version != null) {
// Initialize version upon creation.
String field = version.value();
int initial = version.initial();
listParams.add(new DBParam(field, initial));
}
// </ian>
} finally {
fieldNameConverterLock.readLock().unlock();
}
Connection conn = getProvider().getConnection();
try {
Method pkMethod = Common.getPrimaryKeyMethod(type);
back =
peer(
type,
provider.insertReturningKey(
this,
conn,
Common.getPrimaryKeyClassType(type),
Common.getPrimaryKeyField(type, getFieldNameConverter()),
pkMethod.getAnnotation(AutoIncrement.class) != null,
table,
listParams.toArray(new DBParam[listParams.size()])));
} finally {
conn.close();
}
relationsCache.remove(type);
back.init();
return back;
}
