SheetsMetadata.java

/*
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.facebook.presto.google.sheets;

import com.facebook.presto.spi.ColumnHandle;
import com.facebook.presto.spi.ColumnMetadata;
import com.facebook.presto.spi.ConnectorSession;
import com.facebook.presto.spi.ConnectorTableHandle;
import com.facebook.presto.spi.ConnectorTableLayout;
import com.facebook.presto.spi.ConnectorTableLayoutHandle;
import com.facebook.presto.spi.ConnectorTableLayoutResult;
import com.facebook.presto.spi.ConnectorTableMetadata;
import com.facebook.presto.spi.Constraint;
import com.facebook.presto.spi.PrestoException;
import com.facebook.presto.spi.SchemaTableName;
import com.facebook.presto.spi.SchemaTablePrefix;
import com.facebook.presto.spi.TableNotFoundException;
import com.facebook.presto.spi.connector.ConnectorMetadata;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;

import javax.inject.Inject;

import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.Set;

import static com.facebook.presto.google.sheets.SheetsErrorCode.SHEETS_UNKNOWN_TABLE_ERROR;
import static com.google.common.collect.ImmutableList.toImmutableList;
import static com.google.common.collect.Iterables.getOnlyElement;
import static java.util.Objects.requireNonNull;

public class SheetsMetadata
        implements ConnectorMetadata
{
    private final SheetsClient sheetsClient;
    private static final List<String> SCHEMAS = ImmutableList.of("default");

    @Inject
    public SheetsMetadata(SheetsClient sheetsClient)
    {
        this.sheetsClient = requireNonNull(sheetsClient, "sheetsClient is null");
    }

    @Override
    public List<String> listSchemaNames(ConnectorSession session)
    {
        return listSchemaNames();
    }

    public List<String> listSchemaNames()
    {
        return SCHEMAS;
    }

    @Override
    public SheetsTableHandle getTableHandle(ConnectorSession session, SchemaTableName tableName)
    {
        requireNonNull(tableName, "tableName is null");
        if (!listSchemaNames(session).contains(tableName.getSchemaName())) {
            return null;
        }

        Optional<SheetsTable> table = sheetsClient.getTable(tableName.getTableName());
        if (!table.isPresent()) {
            return null;
        }

        return new SheetsTableHandle(tableName.getSchemaName(), tableName.getTableName());
    }

    @Override
    public List<ConnectorTableLayoutResult> getTableLayouts(
            ConnectorSession session, ConnectorTableHandle table,
            Constraint<ColumnHandle> constraint, Optional<Set<ColumnHandle>> desiredColumns)
    {
        SheetsTableHandle tableHandle = (SheetsTableHandle) table;
        ConnectorTableLayout layout = new ConnectorTableLayout(new SheetsTableLayoutHandle(tableHandle));
        return ImmutableList.of(new ConnectorTableLayoutResult(layout, constraint.getSummary()));
    }

    @Override
    public ConnectorTableLayout getTableLayout(ConnectorSession session, ConnectorTableLayoutHandle handle)
    {
        return new ConnectorTableLayout(handle);
    }

    @Override
    public ConnectorTableMetadata getTableMetadata(ConnectorSession session, ConnectorTableHandle table)
    {
        Optional<ConnectorTableMetadata> connectorTableMetadata = getTableMetadata(session, ((SheetsTableHandle) table).toSchemaTableName());
        if (!connectorTableMetadata.isPresent()) {
            throw new PrestoException(SHEETS_UNKNOWN_TABLE_ERROR, "Metadata not found for table " + ((SheetsTableHandle) table).getTableName());
        }
        return connectorTableMetadata.get();
    }

    private Optional<ConnectorTableMetadata> getTableMetadata(ConnectorSession session, SchemaTableName tableName)
    {
        if (!listSchemaNames().contains(tableName.getSchemaName())) {
            return Optional.empty();
        }
        Optional<SheetsTable> table = sheetsClient.getTable(tableName.getTableName());
        if (table.isPresent()) {
            List<ColumnMetadata> columns = table.get().getColumnsMetadata().stream()
                    .map(column -> column.toBuilder()
                            .setName(normalizeIdentifier(session, column.getName()))
                            .build())
                    .collect(toImmutableList());

            return Optional.of(new ConnectorTableMetadata(tableName, columns));
        }
        return Optional.empty();
    }

    @Override
    public Map<String, ColumnHandle> getColumnHandles(ConnectorSession session, ConnectorTableHandle tableHandle)
    {
        SheetsTableHandle sheetsTableHandle = (SheetsTableHandle) tableHandle;
        Optional<SheetsTable> table = sheetsClient.getTable(sheetsTableHandle.getTableName());
        if (!table.isPresent()) {
            throw new TableNotFoundException(sheetsTableHandle.toSchemaTableName());
        }

        ImmutableMap.Builder<String, ColumnHandle> columnHandles = ImmutableMap.builder();
        int index = 0;
        List<ColumnMetadata> columns = table.get().getColumnsMetadata().stream()
                .map(column -> column.toBuilder()
                        .setName(normalizeIdentifier(session, column.getName()))
                        .build())
                .collect(toImmutableList());

        for (ColumnMetadata column : columns) {
            columnHandles.put(column.getName(), new SheetsColumnHandle(column.getName(), column.getType(), index));
            index++;
        }
        return columnHandles.build();
    }

    @Override
    public ColumnMetadata getColumnMetadata(ConnectorSession session, ConnectorTableHandle tableHandle, ColumnHandle columnHandle)
    {
        return ((SheetsColumnHandle) columnHandle).getColumnMetadata();
    }

    @Override
    public Map<SchemaTableName, List<ColumnMetadata>> listTableColumns(ConnectorSession session, SchemaTablePrefix prefix)
    {
        requireNonNull(prefix, "prefix is null");
        ImmutableMap.Builder<SchemaTableName, List<ColumnMetadata>> columns = ImmutableMap.builder();
        for (SchemaTableName tableName : listTables(session, Optional.of(prefix.getSchemaName()))) {
            Optional<ConnectorTableMetadata> tableMetadata = getTableMetadata(session, tableName);
            // table can disappear during listing operation
            if (tableMetadata.isPresent()) {
                columns.put(tableName, tableMetadata.get().getColumns());
            }
        }
        return columns.build();
    }

    @Override
    public List<SchemaTableName> listTables(ConnectorSession session, Optional<String> schemaName)
    {
        String schema = schemaName.orElseGet(() -> getOnlyElement(SCHEMAS));

        if (listSchemaNames().contains(schema)) {
            return sheetsClient.getTableNames().stream()
                    .map(tableName -> new SchemaTableName(schema, tableName))
                    .collect(toImmutableList());
        }
        return ImmutableList.of();
    }
}