001/* 002 * (C) Copyright 2018 Nuxeo (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 * pierre 018 */ 019package org.nuxeo.runtime.model; 020 021/** 022 * Descriptors implementing this interface will automatically be registered within the default registry in 023 * {@code DefaultComponent}. 024 * 025 * @since 10.3 026 */ 027public interface Descriptor { 028 029 String UNIQUE_DESCRIPTOR_ID = ""; 030 031 /** 032 * The descriptor id, descriptors with same id are merged. 033 * <p> 034 * To forbid multiple descriptors use UNIQUE_DESCRIPTOR_ID. 035 * <p> 036 * To forbid merge use a unique value, non-overriden {@code toString()} for exemple. 037 */ 038 String getId(); 039 040 /** 041 * Returns a descriptor representing {@code other} merged into {@code this} 042 * <p> 043 * Default implementation returns {@code other}. 044 * 045 * @return the merged descriptor 046 */ 047 default Descriptor merge(Descriptor other) { 048 return other; 049 } 050 051 /** 052 * During merge if a descriptor whose doesRemove() returns true is encountered, the merge chain is reset and started 053 * again on next descriptor. 054 * <p> 055 * If the last descriptor of same id doesRemove() return true, the descriptor for this id will be {@code null}. 056 */ 057 default boolean doesRemove() { 058 return false; 059 } 060 061}