2 * Copyright 2007 the original author or authors.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
16 package org.wamblee.system.container;
18 import java.util.ArrayList;
19 import java.util.HashSet;
20 import java.util.List;
23 import org.apache.commons.logging.Log;
24 import org.apache.commons.logging.LogFactory;
25 import org.wamblee.general.Pair;
26 import org.wamblee.system.core.AbstractComponent;
27 import org.wamblee.system.core.Component;
28 import org.wamblee.system.core.DefaultScope;
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;
40 * Container consisting of multiple components.
42 * @author Erik Brakkee
44 public class Container extends AbstractComponent<Scope> {
46 private static final Log LOG = LogFactory.getLog(Container.class);
48 private List<Component> _components;
49 private Set<String> _componentNames;
50 private CompositeEdgeFilter _edgeFilter;
51 private boolean _sealed;
54 * Constructs the container
57 * Name of the container
61 * Provided services of the container
63 * Required services by the container.
65 public Container(String aName, Component[] aComponents,
66 ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
67 super(aName, aProvided, aRequired);
68 _components = new ArrayList<Component>();
70 _componentNames = new HashSet<String>();
71 _edgeFilter = new CompositeEdgeFilter();
73 for (Component component : aComponents) {
74 addComponent(component);
78 public Container(String aName) {
79 this(aName, new Component[0], new ProvidedInterface[0],
80 new RequiredInterface[0]);
83 public Container addComponent(Component aComponent) {
85 if (aComponent.getContext() != null) {
86 throw new SystemAssemblyException(
87 "Inconsistent hierarchy, component '"
88 + aComponent.getName()
89 + "' is already part of another hierarchy");
91 if (_componentNames.contains(aComponent.getName())) {
92 throw new SystemAssemblyException("Duplicate component '"
93 + aComponent.getName() + "'");
95 _components.add(aComponent);
96 _componentNames.add(aComponent.getName());
97 aComponent.addContext(getQualifiedName());
102 * Explictly connects required and provided interfaces.
103 * @param aClientComponent Client component, may not be null.
104 * @param aRequiredInterface Required interface. If null it means all required interfaces.
105 * @param aServerComponent Server component to connect to. If null, it means that no server components
106 * may be connected to and the provider of the required interface will be null.
107 * @param aProvidedInterface Provided interface. If null, it means that there is no restriction on the
108 * name of the provided interface and that it is automatically selected.
110 public void connectRequiredProvided(String aClientComponent, String aRequiredInterface,
111 String aServerComponent, String aProvidedInterface) {
114 _edgeFilter.add(new ConnectRequiredProvidedEdgeFilter(aClientComponent, aRequiredInterface, aServerComponent, aProvidedInterface));
118 * Explicitly connects a externally required interface to an internally required interface.
119 * @param aComponent Component requiring the interface (must be non-null).
120 * @param aRequiredInterface Required interface of the component (must be non-null).
121 * @param aExternalRequiredInterface Externally required interface (must be non-null).
123 public void connectExternalRequired(String aComponent, String aRequiredInterface,
124 String aExternalRequiredInterface) {
127 _edgeFilter.add(new ConnectRequiredExternallyRequiredEdgeFilter(
128 aComponent, aRequiredInterface, aExternalRequiredInterface));
131 public void connectExternalProvided(String aExternalProvided, String aComponent, String aProvidedInterface) {
134 _edgeFilter.add(new ConnectExternalProvidedProvidedFilter(aExternalProvided, aComponent, aProvidedInterface));
139 public Container addProvidedInterface(ProvidedInterface aProvided) {
141 super.addProvidedInterface(aProvided);
146 public Container addRequiredInterface(RequiredInterface aRequired) {
148 super.addRequiredInterface(aRequired);
153 public void addContext(String aContext) {
154 super.addContext(aContext);
155 for (Component component : _components) {
156 component.addContext(aContext);
161 * Validates the components together to check that there are no required
162 * services not in the required list and no services in the provided list
163 * that cannot be provided. Also logs a warning in case of superfluous
166 * @throws SystemAssemblyException
167 * in case of any validation problems.
169 public void validate() {
170 doStartOptionalDryRun(null, true);
174 * Seal the container, meaning that no further components or interfaces may
182 * Checks if the container is sealed.
184 * @return True iff the container is sealed.
186 public boolean isSealed() {
191 * Utility method to start with an empty external scope. This is useful for
192 * top-level containers which are not part of another container.
196 public Scope start() {
197 Scope scope = new DefaultScope(getProvidedInterfaces());
198 return super.start(scope);
202 protected Scope doStart(Scope aExternalScope) {
205 Scope scope = new DefaultScope(getProvidedInterfaces(), aExternalScope);
206 ComponentGraph graph = doStartOptionalDryRun(scope, false);
207 exposeProvidedInterfaces(graph, aExternalScope, scope);
212 private void exposeProvidedInterfaces(ComponentGraph aGraph, Scope aExternalScope,
213 Scope aInternalScope) {
214 for (Pair<ProvidedInterface,ProvidedInterface> mapping:
215 aGraph.findExternalProvidedInterfaceMapping()) {
216 Object svc = aInternalScope.getInterfaceImplementation(mapping.getSecond(), Object.class);
217 addInterface(mapping.getFirst(), svc, aExternalScope);
221 private ComponentGraph doStartOptionalDryRun(Scope aScope, boolean aDryRun) {
222 ComponentGraph graph = createComponentGraph();
228 LOG.info("Starting '" + getQualifiedName() + "'");
230 List<Component> started = new ArrayList<Component>();
231 for (Component component : _components) {
233 // Start the service.
235 Object runtime = component.start(aScope);
236 aScope.addRuntime(component, runtime);
237 started.add(component);
239 } catch (SystemAssemblyException e) {
241 } catch (RuntimeException e) {
242 LOG.error(getQualifiedName() + ": could not start '"
243 + component.getQualifiedName() + "'", e);
244 stopAlreadyStartedComponents(started, aScope);
251 private ComponentGraph createComponentGraph() {
252 ComponentGraph graph = new ComponentGraph();
253 for (RequiredInterface req : getRequiredInterfaces()) {
254 graph.addRequiredInterface(this, req);
256 for (Component comp : _components) {
257 graph.addComponent(comp);
259 for (ProvidedInterface prov: getProvidedInterfaces()) {
260 graph.addProvidedInterface(this, prov);
263 graph.addEdgeFilter(_edgeFilter);
267 private void stopAlreadyStartedComponents(List<Component> aStarted,
269 // an exception occurred, stop the successfully started
271 for (int i = aStarted.size() - 1; i >= 0; i--) {
273 Component component = aStarted.get(i);
274 aStarted.get(i).stop(aScope.getRuntime(component));
275 } catch (Throwable t) {
276 LOG.error(getQualifiedName() + ": error stopping "
277 + aStarted.get(i).getQualifiedName());
283 protected void doStop(Scope aScope) {
284 for (int i = _components.size() - 1; i >= 0; i--) {
285 Component component = _components.get(i);
286 Object runtime = aScope.getRuntime(component);
287 component.stop(runtime);
291 private void checkSealed() {
293 throw new SystemAssemblyException("Container is sealed");