modules/metastorage-client/src/main/java/org/apache/ignite/internal/metastorage/client/StatementResult.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.ignite.internal.metastorage.client;

import static org.apache.ignite.lang.ErrorGroups.MetaStorage.OP_EXECUTION_ERR;

import java.nio.ByteBuffer;
import org.apache.ignite.internal.metastorage.common.MetaStorageException;

/**
 * Simple result of statement execution, backed by byte[] array.
 * Provides some shortcut methods to represent the values of some primitive types.
 */
public class StatementResult {
    /** Result data. */
    private final byte[] result;

    /**
     * Constructs result from the byte array.
     *
     * @param result byte array.
     */
    public StatementResult(byte[] result) {
        this.result = result;
    }

    /**
     * Constructs result from the boolean value.
     *
     * @param result boolean.
     */
    public StatementResult(boolean result) {
        this.result = new byte[] {(byte) (result ? 1 : 0)};
    }

    /**
     * Constructs result from the int value.
     *
     * @param result int.
     */
    public StatementResult(int result) {
        this.result = ByteBuffer.allocate(4).putInt(result).array();
    }

    /**
     * Returns result value as a boolean.
     *
     * @return boolean result.
     * @throws ResultConversionException if boolean conversion is not possible, or can have ambiguous behaviour.
     */
    public boolean getAsBoolean() {
        if (result.length != 1) {
            throw new ResultConversionException("Result can't be interpreted as boolean");
        }

        return result[0] != 0;

    }

    /**
     * Returns result as an int.
     *
     * @return int result.
     * @throws ResultConversionException if int conversion is not possible, or can have ambiguous behaviour.
     */
    public Integer getAsInt() {
        if (result.length != 4) {
            throw new ResultConversionException("Result can't be interpreted as int");
        }

        return ByteBuffer.wrap(result).getInt();
    }

    /**
     * Returns backed byte array.
     *
     * @return backed byte array.
     */
    public byte[] bytes() {
        return result;
    }

    /**
     * Exception to propagate result type conversion issues.
     */
    public static class ResultConversionException extends MetaStorageException {

        /**
         * Constructs new conversion exception.
         *
         * @param msg exception message.
         */
        public ResultConversionException(String msg) {
            super(OP_EXECUTION_ERR, msg);
        }
    }
}