| 1 | // Copyright 2004-2007 Jean-Francois Poilpret |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | package net.sourceforge.hiveutils.service.impl; |
| 16 | |
| 17 | import java.util.ArrayList; |
| 18 | import java.util.HashMap; |
| 19 | import java.util.Iterator; |
| 20 | import java.util.List; |
| 21 | import java.util.Map; |
| 22 | |
| 23 | import org.apache.commons.logging.Log; |
| 24 | import org.apache.hivemind.ApplicationRuntimeException; |
| 25 | import org.apache.hivemind.schema.Translator; |
| 26 | import org.apache.hivemind.service.EventLinker; |
| 27 | import org.apache.hivemind.util.ConstructorUtils; |
| 28 | import org.apache.hivemind.util.PropertyUtils; |
| 29 | |
| 30 | import net.sourceforge.hiveutils.service.ObjectBuilder; |
| 31 | import net.sourceforge.hiveutils.service.ObjectBuilderListener; |
| 32 | |
| 33 | /** |
| 34 | * Implementation of the <code>ObjectBuilder</code> service. |
| 35 | * |
| 36 | * @author Jean-Francois Poilpret |
| 37 | */ |
| 38 | public class ObjectBuilderImpl implements ObjectBuilder |
| 39 | { |
| 40 | public ObjectBuilderImpl(Log logger, |
| 41 | Map<String, ObjectContribution> config, |
| 42 | Translator objectTranslator, |
| 43 | EventLinker linker) |
| 44 | { |
| 45 | _logger = logger; |
| 46 | _linker = linker; |
| 47 | _objectTranslator = objectTranslator; |
| 48 | _config = config; |
| 49 | |
| 50 | _cache = new HashMap<CachedObjectKey, Object>(); |
| 51 | _listeners = new ArrayList<ObjectBuilderListener>(); |
| 52 | |
| 53 | /* |
| 54 | List objectsToLoad = new ArrayList(); |
| 55 | Iterator i = config.values().iterator(); |
| 56 | while (i.hasNext()) |
| 57 | { |
| 58 | ObjectContribution contrib = (ObjectContribution) i.next(); |
| 59 | if (contrib.isEagerLoad()) |
| 60 | { |
| 61 | contrib.setCached(true); |
| 62 | objectsToLoad.add(contrib.getName()); |
| 63 | } |
| 64 | } |
| 65 | // Create eager-loaded objects (#### bug here? why? temporarily comment out) |
| 66 | i = objectsToLoad.iterator(); |
| 67 | while (i.hasNext()) |
| 68 | { |
| 69 | //#### Should we catch all exceptions here? |
| 70 | create((String) i.next()); |
| 71 | } |
| 72 | */ |
| 73 | } |
| 74 | |
| 75 | synchronized public void addObjectBuilderListener(ObjectBuilderListener listener) |
| 76 | { |
| 77 | _listeners.add(listener); |
| 78 | } |
| 79 | |
| 80 | synchronized public void removeObjectBuilderListener(ObjectBuilderListener listener) |
| 81 | { |
| 82 | _listeners.remove(listener); |
| 83 | } |
| 84 | |
| 85 | synchronized private void fireObjectCreated(String name, Object object) |
| 86 | { |
| 87 | for (ObjectBuilderListener listener: _listeners) |
| 88 | { |
| 89 | listener.objectCreated(name, object); |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | @SuppressWarnings("unchecked") |
| 94 | public<T> T get(String name, Object... args) |
| 95 | { |
| 96 | return (T) _cache.get(new CachedObjectKey(name, args)); |
| 97 | } |
| 98 | |
| 99 | @SuppressWarnings("unchecked") |
| 100 | public<T> T create(String name, Object... userArgs) |
| 101 | { |
| 102 | // First find if the object is in the cache |
| 103 | T object = (T) _cache.get(new CachedObjectKey(name, userArgs)); |
| 104 | if (object != null) |
| 105 | { |
| 106 | return object; |
| 107 | } |
| 108 | |
| 109 | // Now find if there is a configuration for it |
| 110 | ObjectContribution contrib = _config.get(name); |
| 111 | if (contrib == null) |
| 112 | { |
| 113 | _logger.info("create() has no contribution for object <" + name + ">"); |
| 114 | return null; |
| 115 | } |
| 116 | |
| 117 | // Build the object with constructor injection first |
| 118 | object = (T) injectConstructor(contrib, userArgs); |
| 119 | |
| 120 | // Then add setter injection |
| 121 | injectSetters(object, contrib); |
| 122 | |
| 123 | // Finally add listeners |
| 124 | injectListeners(object, contrib); |
| 125 | |
| 126 | if (contrib.isCached()) |
| 127 | { |
| 128 | _cache.put(new CachedObjectKey(name, userArgs), object); |
| 129 | } |
| 130 | |
| 131 | _logger.debug("create() just created object: " + name); |
| 132 | fireObjectCreated(name, object); |
| 133 | return object; |
| 134 | } |
| 135 | |
| 136 | private Object injectConstructor(ObjectContribution contrib, Object[] userArgs) |
| 137 | { |
| 138 | // Build the object with constructor injection first |
| 139 | String name = contrib.getName(); |
| 140 | List ctorArgs = contrib.getConstructorInjections(); |
| 141 | Object[] args = new Object[ctorArgs.size()]; |
| 142 | Iterator i = ctorArgs.iterator(); |
| 143 | int j = 0; |
| 144 | int k = 0; |
| 145 | while (i.hasNext()) |
| 146 | { |
| 147 | InjectObjectInformation inject = (InjectObjectInformation) i.next(); |
| 148 | if (inject != null) |
| 149 | { |
| 150 | args[j++] = getObject(inject); |
| 151 | } |
| 152 | else if (k < userArgs.length) |
| 153 | { |
| 154 | args[j++] = userArgs[k++]; |
| 155 | } |
| 156 | else |
| 157 | { |
| 158 | _logger.error("create() has not enough user arguments for object <" + |
| 159 | name + ">"); |
| 160 | throw new ApplicationRuntimeException( |
| 161 | "create() has not enough user arguments for object <" + name + ">"); |
| 162 | } |
| 163 | } |
| 164 | if (k != userArgs.length) |
| 165 | { |
| 166 | _logger.info("Too many user arguments passed to create() for object <" + |
| 167 | name + ">"); |
| 168 | } |
| 169 | return ConstructorUtils.invokeConstructor(contrib.getObjectClass(), args); |
| 170 | } |
| 171 | |
| 172 | private void injectSetters(Object object, ObjectContribution contrib) |
| 173 | { |
| 174 | // Then add setter injection |
| 175 | Map<String, InjectObjectInformation> setters = contrib.getSetterInjections(); |
| 176 | for (Map.Entry<String, InjectObjectInformation> entry: setters.entrySet()) |
| 177 | { |
| 178 | PropertyUtils.write(object, entry.getKey(), getObject(entry.getValue())); |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | public void injectListeners(Object object, ObjectContribution contrib) |
| 183 | { |
| 184 | for (ListenerContribution listener: contrib.getListeners()) |
| 185 | { |
| 186 | addEventListener(object, listener.getObject(), listener.getEvent()); |
| 187 | } |
| 188 | } |
| 189 | |
| 190 | private void addEventListener(Object producer, |
| 191 | InjectObjectInformation listener, |
| 192 | String event) |
| 193 | { |
| 194 | //#### Bad location, no? |
| 195 | _linker.addEventListener(producer, |
| 196 | event, |
| 197 | getObject(listener), |
| 198 | listener.getLocation()); |
| 199 | } |
| 200 | |
| 201 | private Object getObject(InjectObjectInformation inject) |
| 202 | { |
| 203 | return _objectTranslator.translate( inject.getModule(), |
| 204 | inject.getType(), |
| 205 | inject.getObject(), |
| 206 | inject.getLocation()); |
| 207 | } |
| 208 | |
| 209 | // Class to hold the key of a cached object (name + args) |
| 210 | static private class CachedObjectKey |
| 211 | { |
| 212 | public CachedObjectKey(String name, Object[] args) |
| 213 | { |
| 214 | // CSOFF: MagicNumberCheck |
| 215 | _name = name; |
| 216 | _args = args; |
| 217 | int hash = _name.hashCode() * 4321; |
| 218 | for (int i = 0; i < _args.length; i++) |
| 219 | { |
| 220 | if (_args[i] != null) |
| 221 | { |
| 222 | hash += _args[i].hashCode() * (567 + i); |
| 223 | } |
| 224 | } |
| 225 | _hash = hash; |
| 226 | // CSON: MagicNumberCheck |
| 227 | } |
| 228 | |
| 229 | public int hashCode() |
| 230 | { |
| 231 | return _hash; |
| 232 | } |
| 233 | |
| 234 | public boolean equals(Object o) |
| 235 | { |
| 236 | if (!(o instanceof CachedObjectKey)) |
| 237 | { |
| 238 | return false; |
| 239 | } |
| 240 | CachedObjectKey that = (CachedObjectKey) o; |
| 241 | if (!that._name.equals(this._name)) |
| 242 | { |
| 243 | return false; |
| 244 | } |
| 245 | if (that._args.length != this._args.length) |
| 246 | { |
| 247 | return false; |
| 248 | } |
| 249 | for (int i = 0; i < _args.length; i++) |
| 250 | { |
| 251 | if (that._args[i] == this._args[i]) |
| 252 | { |
| 253 | continue; |
| 254 | } |
| 255 | if ( that._args[i] != null |
| 256 | && !that._args[i].equals(this._args[i])) |
| 257 | { |
| 258 | return false; |
| 259 | } |
| 260 | } |
| 261 | return true; |
| 262 | } |
| 263 | |
| 264 | private final String _name; |
| 265 | private final Object[] _args; |
| 266 | private final int _hash; |
| 267 | } |
| 268 | |
| 269 | private final Log _logger; |
| 270 | private final EventLinker _linker; |
| 271 | private final Map<String, ObjectContribution> _config; |
| 272 | private final Map<CachedObjectKey, Object> _cache; |
| 273 | private final Translator _objectTranslator; |
| 274 | private final List<ObjectBuilderListener> _listeners; |
| 275 | } |