Examples with QueryPaginationInput com.amplifyframework.core.model.query.QueryPaginationInput used on opensource projects

Example 1 with QueryPaginationInput

use of com.amplifyframework.core.model.query.QueryPaginationInput in project amplify-android by aws-amplify.

the class SQLiteCommandFactory method queryFor.

@NonNull
@Override
public SqlCommand queryFor(@NonNull ModelSchema modelSchema, @NonNull QueryOptions options) throws DataStoreException {
    final SQLiteTable table = SQLiteTable.fromSchema(modelSchema);
    final String tableName = table.getName();
    StringBuilder rawQuery = new StringBuilder();
    StringBuilder selectColumns = new StringBuilder();
    StringBuilder joinStatement = new StringBuilder();
    final List<Object> bindings = new ArrayList<>();
    // Track the list of columns to return, along with the alias for the corresponding table
    Map<String, List<SQLiteColumn>> columns = new HashMap<>();
    columns.put(table.getName(), table.getSortedColumns());
    Map<String, Integer> tableCount = new HashMap<>();
    tableCount.put(tableName, 1);
    // Joins the foreign keys
    recursivelyBuildJoins(table, columns, joinStatement, tableCount, tableName);
    // Convert columns to comma-separated column names
    boolean firstTable = true;
    for (String tableAlias : columns.keySet()) {
        if (!firstTable) {
            selectColumns.append(",").append(SqlKeyword.DELIMITER);
        } else {
            firstTable = false;
        }
        Iterator<SQLiteColumn> columnsIterator = Objects.requireNonNull(columns.get(tableAlias)).iterator();
        while (columnsIterator.hasNext()) {
            final SQLiteColumn column = columnsIterator.next();
            String columnName = column.getQuotedColumnName().replace(column.getTableName(), tableAlias);
            selectColumns.append(columnName);
            // Alias columns with a unique alias to avoid duplicate column names or alias names
            String columnAlias = column.getAliasedName() + tableAlias.substring(column.getTableName().length());
            selectColumns.append(SqlKeyword.DELIMITER).append(SqlKeyword.AS).append(SqlKeyword.DELIMITER).append(Wrap.inBackticks(columnAlias));
            if (columnsIterator.hasNext()) {
                selectColumns.append(",").append(SqlKeyword.DELIMITER);
            }
        }
    }
    // Start SELECT statement.
    // SELECT columns FROM tableName
    rawQuery.append(SqlKeyword.SELECT).append(SqlKeyword.DELIMITER).append(selectColumns.toString()).append(SqlKeyword.DELIMITER).append(SqlKeyword.FROM).append(SqlKeyword.DELIMITER).append(Wrap.inBackticks(tableName));
    // LEFT JOIN tableTwo ON tableName.id=tableTwo.foreignKey
    if (!joinStatement.toString().isEmpty()) {
        rawQuery.append(SqlKeyword.DELIMITER).append(joinStatement.toString());
    }
    // Append predicates.
    // WHERE condition
    final QueryPredicate predicate = options.getQueryPredicate();
    if (!QueryPredicates.all().equals(predicate)) {
        final SQLPredicate sqlPredicate = new SQLPredicate(predicate);
        bindings.addAll(sqlPredicate.getBindings());
        String sqlPredicateString = sqlPredicate.toString();
        if (predicate instanceof QueryPredicateOperation) {
            QueryPredicateOperation<?> predicateOperation = (QueryPredicateOperation<?>) predicate;
            String predicateOperationField = predicateOperation.field();
            if (predicateOperationField.equals(PrimaryKey.fieldName()) && predicateOperation.modelName() == null && predicateOperation.operator().type() == QueryOperator.Type.EQUAL) {
                // The WHERE condition is Where.id("some-ID") but no model name is given.
                sqlPredicateString = sqlPredicateString.replace(predicateOperationField, tableName + "." + predicateOperationField);
            }
        }
        rawQuery.append(SqlKeyword.DELIMITER).append(SqlKeyword.WHERE).append(SqlKeyword.DELIMITER).append(sqlPredicateString);
    }
    // Append order by
    final List<QuerySortBy> sortByList = options.getSortBy();
    if (sortByList != null) {
        rawQuery.append(SqlKeyword.DELIMITER).append(SqlKeyword.ORDER_BY).append(SqlKeyword.DELIMITER);
        Iterator<QuerySortBy> sortByIterator = sortByList.iterator();
        while (sortByIterator.hasNext()) {
            final QuerySortBy sortBy = sortByIterator.next();
            String modelName = Wrap.inBackticks(sortBy.getModelName());
            String fieldName = Wrap.inBackticks(sortBy.getField());
            if (modelName == null) {
                modelName = Wrap.inBackticks(tableName);
            }
            final String columnName = modelName + "." + fieldName;
            rawQuery.append(columnName).append(SqlKeyword.DELIMITER).append(SqlKeyword.fromQuerySortOrder(sortBy.getSortOrder()));
            if (sortByIterator.hasNext()) {
                rawQuery.append(",").append(SqlKeyword.DELIMITER);
            }
        }
    }
    // Append pagination after order by
    final QueryPaginationInput paginationInput = options.getPaginationInput();
    if (paginationInput != null) {
        rawQuery.append(SqlKeyword.DELIMITER).append(SqlKeyword.LIMIT).append(SqlKeyword.DELIMITER).append("?").append(SqlKeyword.DELIMITER).append(SqlKeyword.OFFSET).append(SqlKeyword.DELIMITER).append("?");
        bindings.add(paginationInput.getLimit());
        bindings.add(paginationInput.getPage() * paginationInput.getLimit());
    }
    rawQuery.append(";");
    final String queryString = rawQuery.toString();
    return new SqlCommand(table.getName(), queryString, bindings);
}