com.hazelcast.query.extractor.ValueReader Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2020, Hazelcast, Inc. All Rights Reserved.
*
* 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.hazelcast.query.extractor;
/**
* Enables reading the value of the attribute specified by the path
*
* The path may be:
* - simple -> it includes a single attribute only, like "name"
*
- nested -> it includes more than a single attribute separated with a dot (.), e.g. "person.address.city"
*
*
* The path may also include array elements:
* - specific quantifier, like "person.leg[1]" -> returns the leg with index 1
*
- wildcard quantifier, like "person.leg[any]" -> returns all legs
*
*
* The wildcard quantifier may be used multiple times, like "person.leg[any].finger[any]" which returns all fingers
* from all legs.
*/
public abstract class ValueReader {
/**
* Read the value of the attribute specified by the path and returns the result via the callback.
*
* @param path attribute to read the value from
* @param callback callback to call with the value. May be called more than once in case of wildcards.
* @param Type of the value to read
* @throws ValueReadingException in case of any reading errors. If an exception occurs the callback won't
* be called at all
*/
public abstract void read(String path, ValueCallback callback) throws ValueReadingException;
/**
* Read the value of the attribute specified by the path and returns the result directly to the collector.
*
* @param path attribute to read the value from
* @param collector collector to collect the result with. May collect more than one result in case of wildcards.
* @param Type of the value to read
* @throws ValueReadingException in case of any reading errors. If an exception occurs the collector won't
* be called at all
*/
public abstract void read(String path, ValueCollector collector) throws ValueReadingException;
}