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.EdgeFilter;
35 import org.wamblee.system.graph.component.ComponentGraph;
36 import org.wamblee.system.graph.component.ConnectRequiredExternallyRequiredEdgeFilter;
37 import org.wamblee.system.graph.component.ConnectRequiredProvidedEdgeFilter;
38 import org.wamblee.system.graph.component.RequiredProvidedEdgeFactory;
41 * Container consisting of multiple components.
43 * @author Erik Brakkee
45 public class Container extends AbstractComponent<Scope> {
47 private static final Log LOG = LogFactory.getLog(Container.class);
49 private List<Component> _components;
50 private Set<String> _componentNames;
51 private CompositeEdgeFilter _edgeFilter;
52 private boolean _sealed;
55 * Constructs the container
58 * Name of the container
62 * Provided services of the container
64 * Required services by the container.
66 public Container(String aName, Component[] aComponents,
67 ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
68 super(aName, aProvided, aRequired);
69 _components = new ArrayList<Component>();
71 _componentNames = new HashSet<String>();
72 _edgeFilter = new CompositeEdgeFilter();
74 for (Component component : aComponents) {
75 addComponent(component);
79 public Container(String aName) {
80 this(aName, new Component[0], new ProvidedInterface[0],
81 new RequiredInterface[0]);
84 public Container addComponent(Component aComponent) {
86 if (aComponent.getContext() != null) {
87 throw new SystemAssemblyException(
88 "Inconsistent hierarchy, component '"
89 + aComponent.getName()
90 + "' is already part of another hierarchy");
92 if (_componentNames.contains(aComponent.getName())) {
93 throw new SystemAssemblyException("Duplicate component '"
94 + aComponent.getName() + "'");
96 _components.add(aComponent);
97 _componentNames.add(aComponent.getName());
98 aComponent.addContext(getQualifiedName());
103 * Explictly connects required and provided interfaces.
104 * @param aClientComponent Client component, may not be null.
105 * @param aRequiredInterface Required interface. If null it means all required interfaces.
106 * @param aServerComponent Server component to connect to. If null, it means that no server components
107 * may be connected to and the provider of the required interface will be null.
108 * @param aProvidedInterface Provided interface. If null, it means that there is no restriction on the
109 * name of the provided interface and that it is automatically selected.
111 public void connectRequiredProvided(String aClientComponent, String aRequiredInterface,
112 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) {
126 _edgeFilter.add(new ConnectRequiredExternallyRequiredEdgeFilter(
127 aComponent, aRequiredInterface, aExternalRequiredInterface));
130 public void connectExternalProvided(String aExternalProvided, String aComponent, String aProvidedInterface) {
133 throw new RuntimeException("not implemented");
138 public Container addProvidedInterface(ProvidedInterface aProvided) {
140 super.addProvidedInterface(aProvided);
145 public Container addRequiredInterface(RequiredInterface aRequired) {
147 super.addRequiredInterface(aRequired);
152 public void addContext(String aContext) {
153 super.addContext(aContext);
154 for (Component component : _components) {
155 component.addContext(aContext);
160 * Validates the components together to check that there are no required
161 * services not in the required list and no services in the provided list
162 * that cannot be provided. Also logs a warning in case of superfluous
165 * @throws SystemAssemblyException
166 * in case of any validation problems.
168 public void validate() {
169 doStartOptionalDryRun(null, true);
173 * Seal the container, meaning that no further components or interfaces may
181 * Checks if the container is sealed.
183 * @return True iff the container is sealed.
185 public boolean isSealed() {
190 * Utility method to start with an empty external scope. This is useful for
191 * top-level containers which are not part of another container.
195 public Scope start() {
196 Scope scope = new DefaultScope(getProvidedInterfaces());
197 return super.start(scope);
201 protected Scope doStart(Scope aExternalScope) {
204 Scope scope = new DefaultScope(getProvidedInterfaces(), aExternalScope);
205 ComponentGraph graph = doStartOptionalDryRun(scope, false);
206 exposeProvidedInterfaces(graph, aExternalScope, scope);
211 private void exposeProvidedInterfaces(ComponentGraph aGraph, Scope aExternalScope,
212 Scope aInternalScope) {
213 for (Pair<ProvidedInterface,ProvidedInterface> mapping:
214 aGraph.findExternalProvidedInterfaceMapping()) {
215 Object svc = aInternalScope.getInterfaceImplementation(mapping.getSecond(), Object.class);
216 addInterface(mapping.getFirst(), svc, aExternalScope);
220 private ComponentGraph doStartOptionalDryRun(Scope aScope, boolean aDryRun) {
221 ComponentGraph graph = createComponentGraph();
227 LOG.info("Starting '" + getQualifiedName() + "'");
229 List<Component> started = new ArrayList<Component>();
230 for (Component component : _components) {
232 // Start the service.
234 Object runtime = component.start(aScope);
235 aScope.addRuntime(component, runtime);
236 started.add(component);
238 } catch (SystemAssemblyException e) {
240 } catch (RuntimeException e) {
241 LOG.error(getQualifiedName() + ": could not start '"
242 + component.getQualifiedName() + "'", e);
243 stopAlreadyStartedComponents(started, aScope);
250 private ComponentGraph createComponentGraph() {
251 ComponentGraph graph = new ComponentGraph();
252 for (RequiredInterface req : getRequiredInterfaces()) {
253 graph.addRequiredInterface(this, req);
255 for (Component comp : _components) {
256 graph.addComponent(comp);
258 for (ProvidedInterface prov: getProvidedInterfaces()) {
259 graph.addProvidedInterface(this, prov);
262 graph.addEdgeFilter(_edgeFilter);
266 private void stopAlreadyStartedComponents(List<Component> aStarted,
268 // an exception occurred, stop the successfully started
270 for (int i = aStarted.size() - 1; i >= 0; i--) {
272 Component component = aStarted.get(i);
273 aStarted.get(i).stop(aScope.getRuntime(component));
274 } catch (Throwable t) {
275 LOG.error(getQualifiedName() + ": error stopping "
276 + aStarted.get(i).getQualifiedName());
282 protected void doStop(Scope aScope) {
283 for (int i = _components.size() - 1; i >= 0; i--) {
284 Component component = _components.get(i);
285 Object runtime = aScope.getRuntime(component);
286 component.stop(runtime);
290 private void checkSealed() {
292 throw new SystemAssemblyException("Container is sealed");