Java tutorial
/* * Copyright 2002-2018 the original author or authors. * * 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 * * https://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 org.springframework.beans.factory.support; import java.util.LinkedHashMap; import java.util.Map; import org.springframework.beans.BeanMetadataElement; import org.springframework.beans.Mergeable; import org.springframework.lang.Nullable; /** * Tag collection class used to hold managed Map values, which may * include runtime bean references (to be resolved into bean objects). * * @author Juergen Hoeller * @author Rob Harrop * @since 27.05.2003 * @param <K> the key type * @param <V> the value type */ @SuppressWarnings("serial") public class ManagedMap<K, V> extends LinkedHashMap<K, V> implements Mergeable, BeanMetadataElement { @Nullable private Object source; @Nullable private String keyTypeName; @Nullable private String valueTypeName; private boolean mergeEnabled; public ManagedMap() { } public ManagedMap(int initialCapacity) { super(initialCapacity); } /** * Set the configuration source {@code Object} for this metadata element. * <p>The exact type of the object will depend on the configuration mechanism used. */ public void setSource(@Nullable Object source) { this.source = source; } @Override @Nullable public Object getSource() { return this.source; } /** * Set the default key type name (class name) to be used for this map. */ public void setKeyTypeName(@Nullable String keyTypeName) { this.keyTypeName = keyTypeName; } /** * Return the default key type name (class name) to be used for this map. */ @Nullable public String getKeyTypeName() { return this.keyTypeName; } /** * Set the default value type name (class name) to be used for this map. */ public void setValueTypeName(@Nullable String valueTypeName) { this.valueTypeName = valueTypeName; } /** * Return the default value type name (class name) to be used for this map. */ @Nullable public String getValueTypeName() { return this.valueTypeName; } /** * Set whether merging should be enabled for this collection, * in case of a 'parent' collection value being present. */ public void setMergeEnabled(boolean mergeEnabled) { this.mergeEnabled = mergeEnabled; } @Override public boolean isMergeEnabled() { return this.mergeEnabled; } @Override @SuppressWarnings("unchecked") public Object merge(@Nullable Object parent) { if (!this.mergeEnabled) { throw new IllegalStateException( "Not allowed to merge when the 'mergeEnabled' property is set to 'false'"); } if (parent == null) { return this; } if (!(parent instanceof Map)) { throw new IllegalArgumentException("Cannot merge with object of type [" + parent.getClass() + "]"); } Map<K, V> merged = new ManagedMap<>(); merged.putAll((Map<K, V>) parent); merged.putAll(this); return merged; } }