001/* 002 * (C) Copyright 2019 Nuxeo SA (http://nuxeo.com/) and others. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * http://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 * 016 * Contributors: 017 * bdelbosc 018 */ 019package org.nuxeo.lib.stream.computation; 020 021import java.util.Map; 022 023import org.nuxeo.lib.stream.log.LogOffset; 024 025/** 026 * Record filtering enables to modify/skip record while it is append or read from a stream. Filter can also be used to add custom code. 027 * 028 * @since 11.1 029 */ 030public interface RecordFilter { 031 032 /** 033 * Initialiaze the filter. 034 */ 035 default void init(Map<String, String> options) { 036 // nothing 037 } 038 039 /** 040 * Called before appending a record to a stream. This hook enables to change the record or to skip it when returning 041 * null. 042 * 043 * @param record the record that will be appended to a stream 044 */ 045 default Record beforeAppend(Record record) { 046 return record; 047 } 048 049 /** 050 * Called after a record is appended to a stream. 051 * 052 * @param record the written record 053 * @param offset the record's offset 054 */ 055 default void afterAppend(Record record, LogOffset offset) { 056 // nothing 057 } 058 059 /** 060 * Called after reading a record. This hook enables to change the record or to skip it when returning null. 061 * 062 * @param record the record 063 * @param offset the offset of the record 064 */ 065 default Record afterRead(Record record, LogOffset offset) { 066 return record; 067 } 068}