001/* 002 * Copyright 2002-2012 the original author or authors. 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 * https://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 017package org.springframework.beans.factory.support; 018 019import java.util.ArrayList; 020import java.util.List; 021 022import org.springframework.beans.BeanMetadataElement; 023import org.springframework.beans.Mergeable; 024 025/** 026 * Tag collection class used to hold managed List elements, which may 027 * include runtime bean references (to be resolved into bean objects). 028 * 029 * @author Rod Johnson 030 * @author Rob Harrop 031 * @author Juergen Hoeller 032 * @since 27.05.2003 033 */ 034@SuppressWarnings("serial") 035public class ManagedList<E> extends ArrayList<E> implements Mergeable, BeanMetadataElement { 036 037 private Object source; 038 039 private String elementTypeName; 040 041 private boolean mergeEnabled; 042 043 044 public ManagedList() { 045 } 046 047 public ManagedList(int initialCapacity) { 048 super(initialCapacity); 049 } 050 051 052 /** 053 * Set the configuration source {@code Object} for this metadata element. 054 * <p>The exact type of the object will depend on the configuration mechanism used. 055 */ 056 public void setSource(Object source) { 057 this.source = source; 058 } 059 060 @Override 061 public Object getSource() { 062 return this.source; 063 } 064 065 /** 066 * Set the default element type name (class name) to be used for this list. 067 */ 068 public void setElementTypeName(String elementTypeName) { 069 this.elementTypeName = elementTypeName; 070 } 071 072 /** 073 * Return the default element type name (class name) to be used for this list. 074 */ 075 public String getElementTypeName() { 076 return this.elementTypeName; 077 } 078 079 /** 080 * Set whether merging should be enabled for this collection, 081 * in case of a 'parent' collection value being present. 082 */ 083 public void setMergeEnabled(boolean mergeEnabled) { 084 this.mergeEnabled = mergeEnabled; 085 } 086 087 @Override 088 public boolean isMergeEnabled() { 089 return this.mergeEnabled; 090 } 091 092 @Override 093 @SuppressWarnings("unchecked") 094 public List<E> merge(Object parent) { 095 if (!this.mergeEnabled) { 096 throw new IllegalStateException("Not allowed to merge when the 'mergeEnabled' property is set to 'false'"); 097 } 098 if (parent == null) { 099 return this; 100 } 101 if (!(parent instanceof List)) { 102 throw new IllegalArgumentException("Cannot merge with object of type [" + parent.getClass() + "]"); 103 } 104 List<E> merged = new ManagedList<E>(); 105 merged.addAll((List<E>) parent); 106 merged.addAll(this); 107 return merged; 108 } 109 110}