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.HashSet;
  21 import java.util.List;
  22 import java.util.Set;
  23
  24 import org.apache.commons.logging.Log;
  25 import org.apache.commons.logging.LogFactory;
  26 import org.wamblee.general.Pair;
  27 import org.wamblee.system.core.AbstractComponent;
  28 import org.wamblee.system.core.Component;
  29 import org.wamblee.system.core.DefaultScope;
  30 import org.wamblee.system.core.ProvidedInterface;
  31 import org.wamblee.system.core.RequiredInterface;
  32 import org.wamblee.system.core.Scope;
  33 import org.wamblee.system.core.SystemAssemblyException;
  34 import org.wamblee.system.graph.CompositeEdgeFilter;
  35 import org.wamblee.system.graph.component.ComponentGraph;
  36 import org.wamblee.system.graph.component.ConnectExternalProvidedProvidedFilter;
  37 import org.wamblee.system.graph.component.ConnectRequiredExternallyRequiredEdgeFilter;
  38 import org.wamblee.system.graph.component.ConnectRequiredProvidedEdgeFilter;
  39
  40 /**
  41  * Container consisting of multiple components.
  42  *
  43  * @author Erik Brakkee
  44  */
  45 public class Container extends AbstractComponent<Scope> {
  46
  47     private static final Log LOG = LogFactory.getLog(Container.class);
  48
  49     private List<Component> _components;
  50     private Set<String> _componentNames;
  51     private CompositeEdgeFilter _edgeFilter;
  52     private boolean _sealed;
  53
  54     /**
  55      * Constructs the container
  56      *
  57      * @param aName
  58      *            Name of the container
  59      * @param aComponents
  60      *            Components.
  61      * @param aProvided
  62      *            Provided services of the container
  63      * @param aRequired
  64      *            Required services by the container.
  65      */
  66     public Container(String aName, Component[] aComponents,
  67             List<ProvidedInterface> aProvided, List<RequiredInterface> aRequired) {
  68         super(aName, aProvided, aRequired);
  69         _components = new ArrayList<Component>();
  70
  71         _componentNames = new HashSet<String>();
  72         _edgeFilter = new CompositeEdgeFilter();
  73         _sealed = false;
  74         for (Component component : aComponents) {
  75             addComponent(component);
  76         }
  77     }
  78
  79     /**
  80      * Constructs the container
  81      *
  82      * @param aName
  83      *            Name of the container
  84      * @param aComponents
  85      *            Components.
  86      * @param aProvided
  87      *            Provided services of the container
  88      * @param aRequired
  89      *            Required services by the container.
  90      */
  91     public Container(String aName, Component[] aComponents,
  92             ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
  93         this(aName, aComponents, Arrays.asList(aProvided), Arrays.asList(aRequired));
  94     }
  95
  96     public Container(String aName) {
  97         this(aName, new Component[0], new ProvidedInterface[0],
  98                 new RequiredInterface[0]);
  99     }
 100
 101     public Container addComponent(Component aComponent) {
 102         checkSealed();
 103         if (aComponent.getContext() != null) {
 104             throw new SystemAssemblyException(
 105                     "Inconsistent hierarchy, component '"
 106                             + aComponent.getName()
 107                             + "' is already part of another hierarchy");
 108         }
 109         if (_componentNames.contains(aComponent.getName())) {
 110             throw new SystemAssemblyException("Duplicate component '"
 111                     + aComponent.getName() + "'");
 112         }
 113         _components.add(aComponent);
 114         _componentNames.add(aComponent.getName());
 115         aComponent.addContext(getQualifiedName());
 116         return this;
 117     }
 118
 119     /**
 120      * Explictly connects required and provided interfaces.
 121      * @param aClientComponent Client component, may not be null.
 122      * @param aRequiredInterface Required interface. If null it means all required interfaces.
 123      * @param aServerComponent Server component to connect to. If null, it means that no server components
 124      *         may be connected to and the provider of the required interface will be null.
 125      * @param aProvidedInterface Provided interface. If null, it means that there is no restriction on the
 126      *   name of the provided interface and that it is automatically selected.
 127      */
 128     public void connectRequiredProvided(String aClientComponent, String aRequiredInterface,
 129             String aServerComponent, String aProvidedInterface) {
 130         checkSealed();
 131         // TODO validate
 132         _edgeFilter.add(new ConnectRequiredProvidedEdgeFilter(aClientComponent, aRequiredInterface, aServerComponent, aProvidedInterface));
 133     }
 134
 135     /**
 136      * Explicitly connects a externally required interface to an internally required interface.
 137      * @param aComponent Component requiring the interface (must be non-null).
 138      * @param aRequiredInterface Required interface of the component (must be non-null).
 139      * @param aExternalRequiredInterface Externally required interface (must be non-null).
 140      */
 141     public void connectExternalRequired(String aComponent, String aRequiredInterface,
 142             String aExternalRequiredInterface) {
 143         checkSealed();
 144         // TODO validate
 145         _edgeFilter.add(new ConnectRequiredExternallyRequiredEdgeFilter(
 146                 aComponent, aRequiredInterface, aExternalRequiredInterface));
 147     }
 148
 149     public void connectExternalProvided(String aExternalProvided, String aComponent, String aProvidedInterface) {
 150         checkSealed();
 151         // TODO validate
 152         _edgeFilter.add(new ConnectExternalProvidedProvidedFilter(aExternalProvided, aComponent, aProvidedInterface));
 153     }
 154
 155
 156     @Override
 157     public Container addProvidedInterface(ProvidedInterface aProvided) {
 158         checkSealed();
 159         super.addProvidedInterface(aProvided);
 160         return this;
 161     }
 162
 163     @Override
 164     public Container addRequiredInterface(RequiredInterface aRequired) {
 165         checkSealed();
 166         super.addRequiredInterface(aRequired);
 167         return this;
 168     }
 169
 170     @Override
 171     public void addContext(String aContext) {
 172         super.addContext(aContext);
 173         for (Component component : _components) {
 174             component.addContext(aContext);
 175         }
 176     }
 177
 178     /**
 179      * Validates the components together to check that there are no required
 180      * services not in the required list and no services in the provided list
 181      * that cannot be provided. Also logs a warning in case of superfluous
 182      * requirements.
 183      *
 184      * @throws SystemAssemblyException
 185      *             in case of any validation problems.
 186      */
 187     public void validate() {
 188         doStartOptionalDryRun(null, true);
 189     }
 190
 191     /**
 192      * Seal the container, meaning that no further components or interfaces may
 193      * be added.
 194      */
 195     public void seal() {
 196         _sealed = true;
 197     }
 198
 199     /**
 200      * Checks if the container is sealed.
 201      *
 202      * @return True iff the container is sealed.
 203      */
 204     public boolean isSealed() {
 205         return _sealed;
 206     }
 207
 208     /**
 209      * Utility method to start with an empty external scope. This is useful for
 210      * top-level containers which are not part of another container.
 211      *
 212      * @return Scope.
 213      */
 214     public Scope start() {
 215         Scope scope = new DefaultScope(getProvidedInterfaces());
 216         return super.start(scope);
 217     }
 218
 219     @Override
 220     protected Scope doStart(Scope aExternalScope) {
 221         checkSealed();
 222         validate();
 223         Scope scope = new DefaultScope(getProvidedInterfaces().toArray(new ProvidedInterface[0]), aExternalScope);
 224         ComponentGraph graph = doStartOptionalDryRun(scope, false);
 225         exposeProvidedInterfaces(graph, aExternalScope, scope);
 226         seal();
 227         return scope;
 228     }
 229
 230     private void exposeProvidedInterfaces(ComponentGraph aGraph, Scope aExternalScope,
 231             Scope aInternalScope) {
 232         for (Pair<ProvidedInterface,ProvidedInterface> mapping:
 233             aGraph.findExternalProvidedInterfaceMapping()) {
 234             Object svc = aInternalScope.getInterfaceImplementation(mapping.getSecond(), Object.class);
 235             addInterface(mapping.getFirst(), svc, aExternalScope);
 236         }
 237     }
 238
 239     private ComponentGraph doStartOptionalDryRun(Scope aScope, boolean aDryRun) {
 240         ComponentGraph graph = createComponentGraph();
 241         graph.validate();
 242         if (!aDryRun) {
 243             graph.link();
 244         }
 245
 246         LOG.info("Starting '" + getQualifiedName() + "'");
 247
 248         List<Component> started = new ArrayList<Component>();
 249         for (Component component : _components) {
 250             try {
 251                 // Start the service.
 252                 if (!aDryRun) {
 253                     Object runtime = component.start(aScope);
 254                     aScope.addRuntime(component, runtime);
 255                     started.add(component);
 256                 }
 257             } catch (SystemAssemblyException e) {
 258                 throw e;
 259             } catch (RuntimeException e) {
 260                 LOG.error(getQualifiedName() + ": could not start '"
 261                         + component.getQualifiedName() + "'", e);
 262                 stopAlreadyStartedComponents(started, aScope);
 263                 throw e;
 264             }
 265         }
 266         return graph;
 267     }
 268
 269     private ComponentGraph createComponentGraph() {
 270         ComponentGraph graph = new ComponentGraph();
 271         for (RequiredInterface req : getRequiredInterfaces()) {
 272             graph.addRequiredInterface(this, req);
 273         }
 274         for (Component comp : _components) {
 275             graph.addComponent(comp);
 276         }
 277         for (ProvidedInterface prov: getProvidedInterfaces()) {
 278             graph.addProvidedInterface(this, prov);
 279         }
 280
 281         graph.addEdgeFilter(_edgeFilter);
 282         return graph;
 283     }
 284
 285     private void stopAlreadyStartedComponents(List<Component> aStarted,
 286             Scope aScope) {
 287         // an exception occurred, stop the successfully started
 288         // components
 289         for (int i = aStarted.size() - 1; i >= 0; i--) {
 290             try {
 291                 Component component = aStarted.get(i);
 292                 aStarted.get(i).stop(aScope.getRuntime(component));
 293             } catch (Throwable t) {
 294                 LOG.error(getQualifiedName() + ": error stopping "
 295                         + aStarted.get(i).getQualifiedName());
 296             }
 297         }
 298     }
 299
 300     @Override
 301     protected void doStop(Scope aScope) {
 302         for (int i = _components.size() - 1; i >= 0; i--) {
 303             Component component = _components.get(i);
 304             Object runtime = aScope.getRuntime(component);
 305             component.stop(runtime);
 306         }
 307     }
 308
 309     private void checkSealed() {
 310         if (_sealed) {
 311             throw new SystemAssemblyException("Container is sealed");
 312         }
 313     }
 314 }