ru.curs.celesta.score.ForeignKey Maven / Gradle / Ivy
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package ru.curs.celesta.score;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
/**
* Foreign key class.
*/
public final class ForeignKey {
private static final Logger LOGGER = LoggerFactory.getLogger(ForeignKey.class);
private final BasicTable parentTable;
private BasicTable referencedTable;
private FKRule deleteRule = FKRule.NO_ACTION;
private FKRule updateRule = FKRule.NO_ACTION;
private String constraintName;
private final NamedElementHolder> columns = new NamedElementHolder<>() {
@Override
protected String getErrorMsg(String name) {
return String
.format("Column '%s' defined more than once in foreign key for table '%s'.",
name, parentTable.getName());
}
};
private final List> referencedColumns = new LinkedList<>();
ForeignKey(BasicTable parentTable) {
if (parentTable == null) {
throw new IllegalArgumentException();
}
this.parentTable = parentTable;
}
public ForeignKey(BasicTable parentTable, BasicTable referencedTable,
String[] columnNames) throws ParseException {
this(parentTable);
for (String n : columnNames) {
addColumn(n);
}
setReferencedTable(referencedTable.getGrain().getName(),
referencedTable.getName());
}
/**
* Sets rule for deletion.
*
* @param deleteBehaviour rule for deletion.
* @throws ParseException When trying to modify the system grain.
*/
public void setDeleteRule(FKRule deleteBehaviour) throws ParseException {
if (deleteBehaviour == null) {
throw new IllegalArgumentException();
}
if (deleteBehaviour == FKRule.SET_NULL) {
checkNullable();
}
parentTable.getGrain().modify();
this.deleteRule = deleteBehaviour;
}
/**
* Sets rule for update.
*
* @param updateBehaviour rule for update.
* @throws ParseException When trying to modify the system grain.
*/
public void setUpdateRule(FKRule updateBehaviour) throws ParseException {
if (updateBehaviour == null) {
throw new IllegalArgumentException();
}
if (updateBehaviour == FKRule.SET_NULL) {
checkNullable();
}
parentTable.getGrain().modify();
this.updateRule = updateBehaviour;
}
private void checkNullable() throws ParseException {
for (Column c : columns) {
if (!c.isNullable()) {
throw new ParseException(String.format("Error while "
+ "creating FK for table '%s': column '%s' is not "
+ "nullable and therefore 'SET NULL' behaviour cannot "
+ "be applied.", parentTable.getName(), c.getName()));
}
}
}
/**
* Unmodified list of columns for the foreign key.
*
* @return
*/
public Map> getColumns() {
return columns.getElements();
}
/**
* Table that the foreign key is part of.
*
* @return
*/
public BasicTable getParentTable() {
return parentTable;
}
/**
* Table that is being referenced by the foreign key.
*
* @return
*/
public BasicTable getReferencedTable() {
return referencedTable;
}
/**
* Returns rule for deletion.
*
* @return
*/
public FKRule getDeleteRule() {
return deleteRule;
}
/**
* Returns rule for update.
*
* @return
*/
public FKRule getUpdateRule() {
return updateRule;
}
/**
* Adds a column. The column must belong to the parent table.
*
* @param columnName column name
* @return
* @throws ParseException in case if the column is not found
*/
void addColumn(String columnName) throws ParseException {
columnName = getParentTable().getGrain().getScore().getIdentifierParser().parse(columnName);
Column c = parentTable.getColumns().get(columnName);
if (c == null) {
throw new ParseException(
String.format(
"Error while creating FK: no column '%s' defined in table '%s'.",
columnName, parentTable.getName()));
}
columns.addElement(c);
}
/**
* Adds table that is being referenced, and finalizes the creation of
* the primary key, adding it to the parent table.
*
* @param grain grain name
* @param table table name
* @throws ParseException in case if there's already a key with the same set of
* fields (not necessarily referencing the same table) in
* the table.
*/
void setReferencedTable(String grain, String table) throws ParseException {
table = getParentTable().getGrain().getScore().getIdentifierParser().parse(table);
// Извлечение гранулы по имени.
Grain gm;
if ("".equals(grain) || parentTable.getGrain().getName().equals(grain)) {
gm = parentTable.getGrain();
} else {
AbstractScore score = parentTable.getGrain().getScore();
gm = score.getGrain(grain);
if (gm.isModified()) {
//TODO:Костыль, используем как флаг того, что гранула начала парситься - must be removed
score.parseGrain(grain);
}
if (!gm.isParsingComplete()) {
throw new ParseException(
String.format(
"Error creating foreign key '%s'-->'%s.%s': "
+ "due to previous parsing errors or "
+ "cycle reference involving grains '%s' and '%s'.",
parentTable.getName(), grain, table,
parentTable.getGrain().getName(), grain));
}
}
// Извлечение таблицы по имени.
BasicTable t = gm.getElement(table, BasicTable.class);
referencedTable = t;
// Проверка того факта, что поля ключа совпадают по типу
// с полями первичного ключа таблицы, на которую ссылка
Map> refpk = referencedTable.getPrimaryKey();
if (columns.size() != refpk.size()) {
throw new ParseException(
String.format(
"Error creating foreign key for table %s: it has different size with PK of table '%s'",
parentTable.getName(), referencedTable.getName()));
}
Iterator> i = referencedTable.getPrimaryKey().values()
.iterator();
for (Column c : columns) {
Column c2 = i.next();
if (c.getClass() != c2.getClass()) {
throw new ParseException(
String.format(
"Error creating foreign key for table %s: its field "
+ "types do not coincide with field types of PK of table '%s'",
parentTable.getName(),
referencedTable.getName()));
}
if (c2 instanceof StringColumn) {
if (((StringColumn) c2).getLength() != ((StringColumn) c)
.getLength()) {
throw new ParseException(
String.format(
"Error creating foreign key for table %s: its string "
+ "field length do not coincide with field length of PK of table '%s'",
parentTable.getName(),
referencedTable.getName()));
}
}
}
// Добавление ключа к родительской таблице (с проверкой того факта, что
// ключа с таким же набором полей не существует).
parentTable.addFK(this);
}
@Override
public int hashCode() {
int result = 0;
for (Column c : columns) {
result ^= c.getName().hashCode();
}
return result;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof ForeignKey) {
ForeignKey fk = (ForeignKey) obj;
if (columns.size() == fk.columns.size()) {
Iterator> i = fk.columns.iterator();
for (Column c : columns) {
Column c2 = i.next();
if (!c.getName().equals(c2.getName())) {
return false;
}
}
return true;
} else {
return false;
}
} else {
return super.equals(obj);
}
}
/**
* Adds a column that is being referenced. A list of such columns is not
* stored in the Foreign Key, for it is necessary to know the table name and
* the primary key of table (references to UNIQUE combinations are not used
* because the support of UNIQUE combinations is missing). The mechanism is
* needed for control of text reference correctness.
*
* @param columnName column name
* @throws ParseException if the column is not present in the table that is
* being referenced
*/
void addReferencedColumn(String columnName) throws ParseException {
// Запускать этот метод можно только после простановки таблицы, на
// которую ссылаемся.
if (referencedTable == null) {
throw new IllegalStateException();
}
columnName = getParentTable().getGrain().getScore().getIdentifierParser().parse(columnName);
Column c = referencedTable.getColumns().get(columnName);
if (c == null) {
throw new ParseException(
String.format(
"Error creating foreign key for table '%s': column '%s' is not defined in table '%s'",
parentTable.getName(), columnName,
referencedTable.getName()
));
}
referencedColumns.add(c);
}
/**
* Finalizes the list of fields that is being referenced by the FK. For ease of
* testing and to save memory, the internal list of references is garbage
* collected right after the finalization. It is neither stored or available
* anywhere. Its sole role is to check the text correctness.
*
* @throws ParseException if the set of fields doesn't correspond to the one
* of the primary key.
*/
void finalizeReference() throws ParseException {
if (referencedTable == null) {
throw new IllegalStateException();
}
Map> pk = referencedTable.getPrimaryKey();
int size = referencedColumns.size();
if (pk.size() != size) {
referencedColumns.clear();
throw new ParseException(String.format(
"Error creating foreign key for table '%s': primary key "
+ "length in table '%s' is %d, but the number of "
+ "reference fields is %d.", parentTable.getName(),
referencedTable.getName(), pk.size(), size));
}
Iterator> i = pk.values().iterator();
for (Column c : referencedColumns) {
Column c2 = i.next();
if (!c.getName().equals(c2.getName())) {
referencedColumns.clear();
throw new ParseException(String.format(
"Error creating foreign key for table '%s': expected primary key "
+ "field '%s'.'%s', but was '%s'.",
parentTable.getName(), referencedTable.getName(),
c2.getName(), c.getName()));
}
}
referencedColumns.clear();
}
/**
* Returns the name of FK constraint (or generates it if it's not provided).
*
* @return
*/
public String getConstraintName() {
if (constraintName != null) {
return constraintName;
}
String result = String.format("fk_%s_%s_%s_%s_%s",
parentTable.getGrain().getName(), parentTable.getName(),
referencedTable.getGrain().getName(), referencedTable.getName(),
columns.getElements().keySet().iterator().next());
result = NamedElement.limitName(result);
LOGGER.trace("{}", result);
return result;
}
/**
* Sets name for FK constraint.
*
* @param constraintName new name of constraint
* @throws ParseException incorrect name of constraint
*/
public void setConstraintName(String constraintName) throws ParseException {
if (constraintName != null) {
parentTable.getGrain().getScore().getIdentifierParser().parse(constraintName);
}
this.constraintName = constraintName;
}
/**
* Deletes the foreign key.
*
* @throws ParseException When trying to modify the system grain.
*/
public void delete() throws ParseException {
parentTable.removeFK(this);
}
}
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