| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You 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 |
| * |
| * http://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.apache.sis.referencing.internal; |
| |
| import java.util.Map; |
| import java.util.HashMap; |
| import org.apache.sis.util.privy.AbstractMap; |
| |
| |
| /** |
| * A map which first looks for values in a user supplied map, then looks in a default map if no value was found |
| * in the user supplied map. This map is for {@link org.apache.sis.referencing.factory.GeodeticObjectFactory} and |
| * other SIS factories internal usage only. |
| * |
| * @author Martin Desruisseaux (Geomatys) |
| */ |
| public class MergedProperties extends AbstractMap<String,Object> { |
| /** |
| * The user supplied properties. |
| */ |
| private final Map<String,?> properties; |
| |
| /** |
| * Fallback for values not found in {@link #properties}. |
| */ |
| private final Map<String,?> defaultProperties; |
| |
| /** |
| * A map containing the merge of user and default properties, or {@code null} if not yet created. |
| * This map is normally never needed. It may be created only if the user creates his own subclass |
| * of {@code GeodeticObjectFactory} or other factories and iterates on this map or asks for its size. |
| */ |
| private transient Map<String,Object> merge; |
| |
| /** |
| * Creates a new map which will merge the given properties on the fly. |
| * |
| * @param properties the user supplied properties. |
| * @param defaultProperties fallback for values not found in {@code properties}. |
| */ |
| public MergedProperties(final Map<String,?> properties, final Map<String,?> defaultProperties) { |
| this.properties = properties; |
| this.defaultProperties = defaultProperties; |
| } |
| |
| /** |
| * Returns an iterator over the user supplied properties together with |
| * the default properties which were not specified in the user's ones. |
| * |
| * @return iterator over merged properties. |
| */ |
| @Override |
| protected EntryIterator<String,Object> entryIterator() { |
| if (merge == null) { |
| merge = new HashMap<>(defaultProperties); |
| merge.putAll(properties); |
| merge.remove(null); |
| } |
| return new IteratorAdapter<>(merge); // That iterator will skip null values. |
| } |
| |
| /** |
| * Returns the value for the given key by first looking in the user supplied map, |
| * then by looking in the default properties if no value were specified in the user map. |
| * If there is no default value, invokes {@link #invisibleEntry(Object)} in last resort. |
| * |
| * @param key the key for which to get the value. |
| * @return the value associated to the given key, or {@code null} if none. |
| */ |
| @Override |
| public Object get(final Object key) { |
| Object value = properties.get(key); |
| if (value == null && !properties.containsKey(key)) { |
| value = defaultProperties.get(key); |
| if (value == null) { |
| value = invisibleEntry(key); |
| } |
| } |
| return value; |
| } |
| |
| /** |
| * Returns the value for an "invisible" entry if no user supplied values were found for that key. |
| * This is used only for "secret" keys used for SIS internal purpose (not for public API). |
| * |
| * <h4>Example</h4> |
| * {@link org.apache.sis.referencing.factory.GeodeticObjectFactory} handles the {@code "mtFactory"} key in a special |
| * way since this is normally not needed for CRS, CS and datum objects, except when creating the SIS implementation |
| * of derived or projected CRS (because of the way we implemented derived CRS). But this is somewhat specific to |
| * SIS, so we do no want to expose this implementation details. |
| * |
| * @param key the key for which to get the value. |
| * @return the value associated to the given key, or {@code null} if none. |
| */ |
| protected Object invisibleEntry(final Object key) { |
| return null; |
| } |
| } |