Examples with JoinTable org.datanucleus.store.rdbms.table.JoinTable used on opensource projects

Example 21 with JoinTable

use of org.datanucleus.store.rdbms.table.JoinTable in project datanucleus-rdbms by datanucleus.

the class CollectionSizeMethod method getExpression.

/* (non-Javadoc)
     * @see org.datanucleus.store.rdbms.sql.method.SQLMethod#getExpression(org.datanucleus.store.rdbms.sql.expression.SQLExpression, java.util.List)
     */
public SQLExpression getExpression(SQLStatement stmt, SQLExpression expr, List<SQLExpression> args) {
    if (args != null && args.size() > 0) {
        throw new NucleusException(Localiser.msg("060015", "size", "CollectionExpression"));
    }
    SQLExpressionFactory exprFactory = stmt.getSQLExpressionFactory();
    if (expr instanceof CollectionLiteral) {
        // Just return the collection size since we have the value
        Collection coll = (Collection) ((CollectionLiteral) expr).getValue();
        return exprFactory.newLiteral(stmt, exprFactory.getMappingForType(int.class, false), Integer.valueOf(coll.size()));
    }
    AbstractMemberMetaData mmd = expr.getJavaTypeMapping().getMemberMetaData();
    if (mmd.isSerialized()) {
        throw new NucleusUserException("Cannot perform Collection.size when the collection is being serialised");
    }
    ApiAdapter api = stmt.getRDBMSManager().getApiAdapter();
    ClassLoaderResolver clr = stmt.getQueryGenerator().getClassLoaderResolver();
    Class elementCls = clr.classForName(mmd.getCollection().getElementType());
    if (!api.isPersistable(elementCls) && mmd.getJoinMetaData() == null) {
        throw new NucleusUserException("Cannot perform Collection.size when the collection<Non-Persistable> is not in a join table");
    }
    String elementType = mmd.getCollection().getElementType();
    RDBMSStoreManager storeMgr = stmt.getRDBMSManager();
    // TODO Allow for interface elements, etc
    JavaTypeMapping ownerMapping = null;
    Table collectionTbl = null;
    if (mmd.getMappedBy() != null) {
        // Bidirectional
        AbstractMemberMetaData elementMmd = mmd.getRelatedMemberMetaData(clr)[0];
        if (mmd.getJoinMetaData() != null || elementMmd.getJoinMetaData() != null) {
            // JoinTable
            collectionTbl = storeMgr.getTable(mmd);
            ownerMapping = ((JoinTable) collectionTbl).getOwnerMapping();
        } else {
            // ForeignKey
            collectionTbl = storeMgr.getDatastoreClass(elementType, clr);
            ownerMapping = collectionTbl.getMemberMapping(elementMmd);
        }
    } else {
        // Unidirectional
        if (mmd.getJoinMetaData() != null) {
            // JoinTable
            collectionTbl = storeMgr.getTable(mmd);
            ownerMapping = ((JoinTable) collectionTbl).getOwnerMapping();
        } else {
            // ForeignKey
            collectionTbl = storeMgr.getDatastoreClass(elementType, clr);
            ownerMapping = ((DatastoreClass) collectionTbl).getExternalMapping(mmd, MappingType.EXTERNAL_FK);
        }
    }
    SelectStatement subStmt = new SelectStatement(stmt, storeMgr, collectionTbl, null, null);
    subStmt.setClassLoaderResolver(clr);
    JavaTypeMapping mapping = storeMgr.getMappingManager().getMappingWithDatastoreMapping(String.class, false, false, clr);
    SQLExpression countExpr = exprFactory.newLiteral(subStmt, mapping, "COUNT(*)");
    ((StringLiteral) countExpr).generateStatementWithoutQuotes();
    subStmt.select(countExpr, null);
    SQLExpression elementOwnerExpr = exprFactory.newExpression(subStmt, subStmt.getPrimaryTable(), ownerMapping);
    SQLExpression ownerIdExpr = exprFactory.newExpression(stmt, expr.getSQLTable(), expr.getSQLTable().getTable().getIdMapping());
    subStmt.whereAnd(elementOwnerExpr.eq(ownerIdExpr), true);
    JavaTypeMapping subqMapping = exprFactory.getMappingForType(Integer.class, false);
    SQLExpression subqExpr = new NumericSubqueryExpression(stmt, subStmt);
    subqExpr.setJavaTypeMapping(subqMapping);
    return subqExpr;
}