wamblee.org Git - utils/blob - system/general/src/main/java/org/wamblee/system/container/Container.java

   1 /*
   2  * Copyright 2007 the original author or authors.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package org.wamblee.system.container;
  17
  18 import java.util.ArrayList;
  19 import java.util.Arrays;
  20 import java.util.List;
  21
  22 import org.apache.commons.logging.Log;
  23 import org.apache.commons.logging.LogFactory;
  24 import org.wamblee.general.Pair;
  25 import org.wamblee.system.core.AbstractComponent;
  26 import org.wamblee.system.core.Component;
  27 import org.wamblee.system.core.DefaultScope;
  28 import org.wamblee.system.core.NamedInterface;
  29 import org.wamblee.system.core.ProvidedInterface;
  30 import org.wamblee.system.core.RequiredInterface;
  31 import org.wamblee.system.core.Scope;
  32 import org.wamblee.system.core.SystemAssemblyException;
  33 import org.wamblee.system.graph.CompositeEdgeFilter;
  34 import org.wamblee.system.graph.component.ComponentGraph;
  35 import org.wamblee.system.graph.component.ConnectExternalProvidedProvidedFilter;
  36 import org.wamblee.system.graph.component.ConnectRequiredExternallyRequiredEdgeFilter;
  37 import org.wamblee.system.graph.component.ConnectRequiredProvidedEdgeFilter;
  38
  39 /**
  40  * Container consisting of multiple components.
  41  *
  42  * @author Erik Brakkee
  43  */
  44 public class Container extends AbstractComponent<Scope> {
  45
  46     private static final Log LOG = LogFactory.getLog(Container.class);
  47
  48     private List<Component> components;
  49     private CompositeEdgeFilter edgeFilter;
  50     private boolean sealed;
  51
  52     /**
  53      * Constructs the container
  54      *
  55      * @param aName
  56      *            Name of the container
  57      * @param aComponents
  58      *            Components.
  59      * @param aProvided
  60      *            Provided services of the container
  61      * @param aRequired
  62      *            Required services by the container.
  63      */
  64     public Container(String aName, Component[] aComponents,
  65             List<ProvidedInterface> aProvided, List<RequiredInterface> aRequired) {
  66         super(aName, aProvided, aRequired);
  67         components = new ArrayList<Component>();
  68
  69         edgeFilter = new CompositeEdgeFilter();
  70         sealed = false;
  71         for (Component component : aComponents) {
  72             addComponent(component);
  73         }
  74     }
  75
  76     /**
  77      * Constructs the container
  78      *
  79      * @param aName
  80      *            Name of the container
  81      * @param aComponents
  82      *            Components.
  83      * @param aProvided
  84      *            Provided services of the container
  85      * @param aRequired
  86      *            Required services by the container.
  87      */
  88     public Container(String aName, Component[] aComponents,
  89             ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
  90         this(aName, aComponents, Arrays.asList(aProvided), Arrays.asList(aRequired));
  91     }
  92
  93     public Container(String aName) {
  94         this(aName, new Component[0], new ProvidedInterface[0],
  95                 new RequiredInterface[0]);
  96     }
  97
  98     public Container addComponent(Component aComponent) {
  99         checkSealed();
 100         if (aComponent.getContext() != null) {
 101             throw new SystemAssemblyException(
 102                     "Inconsistent hierarchy, component '"
 103                             + aComponent.getName()
 104                             + "' is already part of another hierarchy");
 105         }
 106         if ( findComponent(aComponent.getName()) != null ) {
 107             throw new SystemAssemblyException("Duplicate component '"
 108                     + aComponent.getName() + "'");
 109         }
 110         components.add(aComponent);
 111         aComponent.addContext(getQualifiedName());
 112         return this;
 113     }
 114
 115     /**
 116      * Explictly connects required and provided interfaces.
 117      * @param aClientComponent Client component, may not be null.
 118      * @param aRequiredInterface Required interface. If null it means all required interfaces.
 119      * @param aServerComponent Server component to connect to. If null, it means that no server components
 120      *         may be connected to and the provider of the required interface will be null.
 121      * @param aProvidedInterface Provided interface. If null, it means that there is no restriction on the
 122      *   name of the provided interface and that it is automatically selected.
 123      */
 124     public void connectRequiredProvided(String aClientComponent, String aRequiredInterface,
 125             String aServerComponent, String aProvidedInterface) {
 126         checkSealed();
 127         Component client = findComponent(aClientComponent);
 128         Component server = findComponent(aServerComponent);
 129         if ( client == null ) {
 130                 throw new SystemAssemblyException(getQualifiedName() + ": No component '" + aClientComponent + "' in the container");
 131         }
 132         if ( aRequiredInterface != null ) {
 133                 if ( findInterface(client.getRequiredInterfaces(), aRequiredInterface) == null ) {
 134                         throw new SystemAssemblyException(
 135                                         getQualifiedName() + ": Component '" + aClientComponent + "' does not have a required interface named '"
 136                                         + aRequiredInterface + "'");
 137                 }
 138         }
 139         if ( server == null ) {
 140                 throw new SystemAssemblyException("No component '" + aClientComponent + "' in the container");
 141         }
 142         if ( aProvidedInterface != null ) {
 143                 if ( findInterface(server.getProvidedInterfaces(), aProvidedInterface) == null) {
 144                         throw new SystemAssemblyException(
 145                                         getQualifiedName() + ": Component '" + aServerComponent + "' does not have a provided interface named '"
 146                                         + aProvidedInterface + "'");
 147                 }
 148         }
 149         edgeFilter.add(new ConnectRequiredProvidedEdgeFilter(aClientComponent, aRequiredInterface, aServerComponent, aProvidedInterface));
 150     }
 151
 152     /**
 153      * Explicitly connects a externally required interface to an internally required interface.
 154      * @param aComponent Component requiring the interface (must be non-null).
 155      * @param aRequiredInterface Required interface of the component (must be non-null).
 156      * @param aExternalRequiredInterface Externally required interface (must be non-null).
 157      */
 158     public void connectExternalRequired(String aComponent, String aRequiredInterface,
 159             String aExternalRequiredInterface) {
 160         checkSealed();
 161         Component client = findComponent(aComponent);
 162         if ( client == null ) {
 163                 throw new SystemAssemblyException(getQualifiedName() + ": No component '" + aComponent + "' in the container");
 164         }
 165         if ( aRequiredInterface != null ) {
 166                 if ( findInterface(client.getRequiredInterfaces(), aRequiredInterface) == null ) {
 167                         throw new SystemAssemblyException(
 168                                         getQualifiedName() + ": Component '" + aComponent + "' does not have a required interface named '"
 169                                         + aRequiredInterface + "'");
 170                 }
 171         }
 172         if ( aExternalRequiredInterface != null) {
 173                 if ( findInterface(getRequiredInterfaces(), aExternalRequiredInterface) == null ) {
 174                         throw new SystemAssemblyException(
 175                                         getQualifiedName() + ": container does not have a required interface named '"
 176                                         + aExternalRequiredInterface + "'");
 177                 }
 178         }
 179         edgeFilter.add(new ConnectRequiredExternallyRequiredEdgeFilter(
 180                 aComponent, aRequiredInterface, aExternalRequiredInterface));
 181     }
 182
 183     public void connectExternalProvided(String aExternalProvided, String aComponent, String aProvidedInterface) {
 184         checkSealed();
 185         Component server = findComponent(aComponent);
 186
 187
 188         if ( server == null ) {
 189                 throw new SystemAssemblyException("No component '" + aComponent + "' in the container");
 190         }
 191         if ( aProvidedInterface != null ) {
 192                 if ( findInterface(server.getProvidedInterfaces(), aProvidedInterface) == null) {
 193                         throw new SystemAssemblyException(
 194                                         getQualifiedName() + ": Component '" + aComponent + "' does not have a provided interface named '"
 195                                         + aProvidedInterface + "'");
 196                 }
 197         }
 198         if ( aExternalProvided != null ) {
 199                 if ( findInterface(getProvidedInterfaces(), aExternalProvided) == null) {
 200                         throw new SystemAssemblyException(
 201                                         getQualifiedName() + ": Container does not have a provided interface named '"
 202                                         + aExternalProvided + "'");
 203                 }
 204         }
 205         edgeFilter.add(new ConnectExternalProvidedProvidedFilter(aExternalProvided, aComponent, aProvidedInterface));
 206     }
 207
 208
 209     @Override
 210     public Container addProvidedInterface(ProvidedInterface aProvided) {
 211         checkSealed();
 212         super.addProvidedInterface(aProvided);
 213         return this;
 214     }
 215
 216     @Override
 217     public Container addRequiredInterface(RequiredInterface aRequired) {
 218         checkSealed();
 219         super.addRequiredInterface(aRequired);
 220         return this;
 221     }
 222
 223     @Override
 224     public void addContext(String aContext) {
 225         super.addContext(aContext);
 226         for (Component component : components) {
 227             component.addContext(aContext);
 228         }
 229     }
 230
 231     /**
 232      * Validates the components together to check that there are no required
 233      * services not in the required list and no services in the provided list
 234      * that cannot be provided. Also logs a warning in case of superfluous
 235      * requirements.
 236      *
 237      * @throws SystemAssemblyException
 238      *             in case of any validation problems.
 239      */
 240     public void validate() {
 241         doStartOptionalDryRun(null, true);
 242     }
 243
 244     /**
 245      * Seal the container, meaning that no further components or interfaces may
 246      * be added.
 247      */
 248     public void seal() {
 249         sealed = true;
 250     }
 251
 252     /**
 253      * Checks if the container is sealed.
 254      *
 255      * @return True iff the container is sealed.
 256      */
 257     public boolean isSealed() {
 258         return sealed;
 259     }
 260
 261     /**
 262      * Utility method to start with an empty external scope. This is useful for
 263      * top-level containers which are not part of another container.
 264      *
 265      * @return Scope.
 266      */
 267     public Scope start() {
 268         Scope scope = new DefaultScope(getProvidedInterfaces());
 269         return super.start(scope);
 270     }
 271
 272     @Override
 273     protected Scope doStart(Scope aExternalScope) {
 274         validate();
 275         Scope scope = new DefaultScope(getProvidedInterfaces().toArray(new ProvidedInterface[0]), aExternalScope);
 276         ComponentGraph graph = doStartOptionalDryRun(scope, false);
 277         exposeProvidedInterfaces(graph, aExternalScope, scope);
 278         seal();
 279         return scope;
 280     }
 281
 282     private void exposeProvidedInterfaces(ComponentGraph aGraph, Scope aExternalScope,
 283             Scope aInternalScope) {
 284         for (Pair<ProvidedInterface,ProvidedInterface> mapping:
 285             aGraph.findExternalProvidedInterfaceMapping()) {
 286             Object svc = aInternalScope.getInterfaceImplementation(mapping.getSecond(), Object.class);
 287             addInterface(mapping.getFirst(), svc, aExternalScope);
 288         }
 289     }
 290
 291     private ComponentGraph doStartOptionalDryRun(Scope aScope, boolean aDryRun) {
 292         ComponentGraph graph = createComponentGraph();
 293         graph.validate();
 294         graph.link();
 295
 296         LOG.info("Starting '" + getQualifiedName() + "'");
 297
 298         List<Component> started = new ArrayList<Component>();
 299         for (Component component : components) {
 300             try {
 301                 // Start the service.
 302                 if (!aDryRun) {
 303                     Object runtime = component.start(aScope);
 304                     aScope.addRuntime(component, runtime);
 305                     started.add(component);
 306                 }
 307             } catch (SystemAssemblyException e) {
 308                 throw e;
 309             } catch (RuntimeException e) {
 310                 LOG.error(getQualifiedName() + ": could not start '"
 311                         + component.getQualifiedName() + "'", e);
 312                 stopAlreadyStartedComponents(started, aScope);
 313                 throw e;
 314             }
 315         }
 316         return graph;
 317     }
 318
 319     private ComponentGraph createComponentGraph() {
 320         ComponentGraph graph = new ComponentGraph();
 321         for (RequiredInterface req : getRequiredInterfaces()) {
 322             graph.addRequiredInterface(this, req);
 323         }
 324         for (Component comp : components) {
 325             graph.addComponent(comp);
 326         }
 327         for (ProvidedInterface prov: getProvidedInterfaces()) {
 328             graph.addProvidedInterface(this, prov);
 329         }
 330
 331         graph.addEdgeFilter(edgeFilter);
 332         return graph;
 333     }
 334
 335     private void stopAlreadyStartedComponents(List<Component> aStarted,
 336             Scope aScope) {
 337         // an exception occurred, stop the successfully started
 338         // components
 339         for (int i = aStarted.size() - 1; i >= 0; i--) {
 340             try {
 341                 Component component = aStarted.get(i);
 342                 aStarted.get(i).stop(aScope.getRuntime(component));
 343             } catch (Throwable t) {
 344                 LOG.error(getQualifiedName() + ": error stopping "
 345                         + aStarted.get(i).getQualifiedName());
 346             }
 347         }
 348     }
 349
 350     @Override
 351     protected void doStop(Scope aScope) {
 352         for (int i = components.size() - 1; i >= 0; i--) {
 353             Component component = components.get(i);
 354             Object runtime = aScope.getRuntime(component);
 355             component.stop(runtime);
 356         }
 357     }
 358
 359     private void checkSealed() {
 360         if (sealed) {
 361             throw new SystemAssemblyException("Container is sealed");
 362         }
 363     }
 364
 365     /**
 366      * Finds a component based on the non-qualified name of the component.
 367      * @param aName Component name.
 368      * @return Component or null if not found.
 369      */
 370     public Component findComponent(String aName) {
 371         for (Component<?> component: components) {
 372                 if ( component.getName().equals(aName)) {
 373                         return component;
 374                 }
 375         }
 376         return null;
 377     }
 378
 379     private static <T extends NamedInterface> T findInterface(List<T> aInterfaces, String aInterfaceName) {
 380         for (T intf: aInterfaces) {
 381                 if ( intf.getName().equals(aInterfaceName)) {
 382                         return intf;
 383                 }
 384         }
 385         return null;
 386     }
 387 }