001/*******************************************************************************
002 * Copyright (c) 2016 Diamond Light Source Ltd. and others.
003 * All rights reserved. This program and the accompanying materials
004 * are made available under the terms of the Eclipse Public License v1.0
005 * which accompanies this distribution, and is available at
006 * http://www.eclipse.org/legal/epl-v10.html
007 *
008 * Contributors:
009 *     Diamond Light Source Ltd - initial API and implementation
010 *******************************************************************************/
011package org.eclipse.january.metadata;
012
013import java.lang.reflect.Method;
014import java.util.HashMap;
015import java.util.Map;
016
017import org.eclipse.january.MetadataException;
018import org.eclipse.january.dataset.LazyDatasetBase;
019import org.eclipse.january.metadata.internal.AxesMetadataImpl;
020import org.eclipse.january.metadata.internal.DimensionMetadataImpl;
021import org.eclipse.january.metadata.internal.ErrorMetadataImpl;
022import org.eclipse.january.metadata.internal.MaskMetadataImpl;
023import org.eclipse.january.metadata.internal.OriginMetadataImpl;
024import org.eclipse.january.metadata.internal.PeemMetadataImpl;
025import org.eclipse.january.metadata.internal.StatisticsMetadataImpl;
026
027public class MetadataFactory {
028
029        private MetadataFactory() {
030        }
031
032        static Map<Class<? extends MetadataType>, Class<? extends MetadataType>> metadataClasses = createMap();
033        private static Map<Class<? extends MetadataType>, Class<? extends MetadataType>> createMap() {
034                Map<Class<? extends MetadataType>, Class<? extends MetadataType>> map = new HashMap<Class<? extends MetadataType>, Class<? extends MetadataType>>();
035                map.put(IMetadata.class, Metadata.class);
036                map.put(ErrorMetadata.class, ErrorMetadataImpl.class);
037                map.put(AxesMetadata.class, AxesMetadataImpl.class);
038                map.put(DimensionMetadata.class, DimensionMetadataImpl.class);
039                map.put(MaskMetadata.class, MaskMetadataImpl.class);
040                map.put(OriginMetadata.class, OriginMetadataImpl.class);
041                map.put(PeemMetadata.class, PeemMetadataImpl.class);
042                map.put(StatisticsMetadata.class, StatisticsMetadataImpl.class);
043                return map;
044        }
045
046        
047        /**
048         * Create a metadata object of given class with given arguments
049         * @param clazz
050         * @param arguments these must match the arguments given in the initialize method specified in the class
051         * @return metadata object or null if type not available
052         * @throws MetadataException if the class cannot be instantiated, the initialize method does not exist, or
053         *  the initialize method could not be called successfully
054         */
055        public static <T extends MetadataType> T createMetadata(Class<T> clazz, Object... arguments) throws MetadataException {
056                @SuppressWarnings("unchecked")
057                Class<T> mdClass = (Class<T>) metadataClasses.get(clazz);
058                if (mdClass == null) {
059                        return null;
060                }
061
062                T obj = null;
063                try {
064                        obj = mdClass.newInstance();
065                } catch (Exception e) {
066                        throw new MetadataException("Could not create metadata object", e);
067                }
068
069                try {
070                        for (Method m : mdClass.getMethods()) {
071                                if (m.getName().equals("initialize")) {
072                                        m.invoke(obj, arguments);
073                                        return obj;
074                                }
075                        }
076                } catch (Exception e) {
077                        throw new MetadataException("Could not initialize object", e);
078                }
079                throw new MetadataException("Could not find initialize method");
080        }
081
082        /**
083         * Register metadata class
084         * @param clazz
085         */
086        public static <T extends MetadataType> void registerClass(Class<T> clazz) {
087                Class<? extends MetadataType> iClass = LazyDatasetBase.findMetadataTypeSubInterfaces(clazz);
088
089                metadataClasses.put(iClass, clazz);
090        }
091}