001/*
002 * Copyright 2002-2017 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.Properties;
020
021import org.springframework.beans.BeanMetadataElement;
022import org.springframework.beans.Mergeable;
023import org.springframework.lang.Nullable;
024
025/**
026 * Tag class which represents a Spring-managed {@link Properties} instance
027 * that supports merging of parent/child definitions.
028 *
029 * @author Rob Harrop
030 * @author Juergen Hoeller
031 * @since 2.0
032 */
033@SuppressWarnings("serial")
034public class ManagedProperties extends Properties implements Mergeable, BeanMetadataElement {
035
036        @Nullable
037        private Object source;
038
039        private boolean mergeEnabled;
040
041
042        /**
043         * Set the configuration source {@code Object} for this metadata element.
044         * <p>The exact type of the object will depend on the configuration mechanism used.
045         */
046        public void setSource(@Nullable Object source) {
047                this.source = source;
048        }
049
050        @Override
051        @Nullable
052        public Object getSource() {
053                return this.source;
054        }
055
056        /**
057         * Set whether merging should be enabled for this collection,
058         * in case of a 'parent' collection value being present.
059         */
060        public void setMergeEnabled(boolean mergeEnabled) {
061                this.mergeEnabled = mergeEnabled;
062        }
063
064        @Override
065        public boolean isMergeEnabled() {
066                return this.mergeEnabled;
067        }
068
069
070        @Override
071        public Object merge(@Nullable Object parent) {
072                if (!this.mergeEnabled) {
073                        throw new IllegalStateException("Not allowed to merge when the 'mergeEnabled' property is set to 'false'");
074                }
075                if (parent == null) {
076                        return this;
077                }
078                if (!(parent instanceof Properties)) {
079                        throw new IllegalArgumentException("Cannot merge with object of type [" + parent.getClass() + "]");
080                }
081                Properties merged = new ManagedProperties();
082                merged.putAll((Properties) parent);
083                merged.putAll(this);
084                return merged;
085        }
086
087}