phoenix-core/src/main/java/org/apache/phoenix/util/json/ObjectToArrayConverter.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.phoenix.util.json;

import java.sql.Array;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.List;

import org.apache.phoenix.schema.types.PDataType;

import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;

/**
 * Converts Objects (presumably lists) into Phoenix arrays.
 */
class ObjectToArrayConverter {

    private final Connection conn;
    private final PDataType elementDataType;
    private final JsonUpsertExecutor.SimpleDatatypeConversionFunction elementConvertFunction;

    /**
     * Instantiate with the array value separator and data type.
     *
     * @param conn Phoenix connection to target database
     * @param elementDataType datatype of the elements of arrays to be created
     */
    public ObjectToArrayConverter(Connection conn, PDataType elementDataType) {
        this.conn = conn;
        this.elementDataType = elementDataType;
        this.elementConvertFunction =
            new JsonUpsertExecutor.SimpleDatatypeConversionFunction(elementDataType, this.conn);
    }

    /**
     * Convert an input delimited string into a phoenix array of the configured type.
     *
     * @param input string containing delimited array values
     * @return the array containing the values represented in the input string
     */
    public Array toArray(Object input) throws SQLException {
        if (input == null) {
            return conn.createArrayOf(elementDataType.getSqlTypeName(), new Object[0]);
        }
        List<?> list = (List<?>) input;
        if (list.isEmpty()) {
            return conn.createArrayOf(elementDataType.getSqlTypeName(), new Object[0]);
        }
        return conn.createArrayOf(elementDataType.getSqlTypeName(),
            Lists.newArrayList(Iterables.transform(list, elementConvertFunction)).toArray());
    }
}