--- /dev/null
+/*
+ * Copyright 2007 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.wamblee.system.container;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.wamblee.general.Pair;
+import org.wamblee.system.core.AbstractComponent;
+import org.wamblee.system.core.Component;
+import org.wamblee.system.core.DefaultScope;
+import org.wamblee.system.core.ProvidedInterface;
+import org.wamblee.system.core.RequiredInterface;
+import org.wamblee.system.core.Scope;
+import org.wamblee.system.core.SystemAssemblyException;
+import org.wamblee.system.graph.component.ComponentGraph;
+
+/**
+ * Container consisting of multiple components.
+ *
+ * @author Erik Brakkee
+ */
+public class Container extends AbstractComponent<Scope> {
+
+ private static final Log LOG = LogFactory.getLog(Container.class);
+
+ private List<Component> _components;
+ private Set<String> _componentNames;
+ private CompositeInterfaceRestriction _restriction;
+ private boolean _sealed;
+
+ /**
+ * Constructs the container
+ *
+ * @param aName
+ * Name of the container
+ * @param aComponents
+ * Components.
+ * @param aProvided
+ * Provided services of the container
+ * @param aRequired
+ * Required services by the container.
+ */
+ public Container(String aName, Component[] aComponents,
+ ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
+ super(aName, aProvided, aRequired);
+ _components = new ArrayList<Component>();
+
+ _componentNames = new HashSet<String>();
+ _restriction = new CompositeInterfaceRestriction();
+ _sealed = false;
+ for (Component component : aComponents) {
+ addComponent(component);
+ }
+ }
+
+ public Container(String aName) {
+ this(aName, new Component[0], new ProvidedInterface[0],
+ new RequiredInterface[0]);
+ }
+
+ public Container addComponent(Component aComponent) {
+ checkSealed();
+ if (aComponent.getContext() != null) {
+ throw new SystemAssemblyException(
+ "Inconsistent hierarchy, component '"
+ + aComponent.getName()
+ + "' is already part of another hierarchy");
+ }
+ if (_componentNames.contains(aComponent.getName())) {
+ throw new SystemAssemblyException("Duplicate component '"
+ + aComponent.getName() + "'");
+ }
+ _components.add(aComponent);
+ _componentNames.add(aComponent.getName());
+ aComponent.addContext(getQualifiedName());
+ return this;
+ }
+
+ /**
+ * Adds an interface restriction for explicitly configuring the relations
+ * between components.
+ *
+ * @param aRestriction
+ * Restriction to add.
+ * @return Reference to this to allow call chaining.
+ */
+ public Container addRestriction(InterfaceRestriction aRestriction) {
+ checkSealed();
+ _restriction.add(aRestriction);
+ return this;
+ }
+
+ @Override
+ public Container addProvidedInterface(ProvidedInterface aProvided) {
+ checkSealed();
+ super.addProvidedInterface(aProvided);
+ return this;
+ }
+
+ @Override
+ public Container addRequiredInterface(RequiredInterface aRequired) {
+ checkSealed();
+ super.addRequiredInterface(aRequired);
+ return this;
+ }
+
+ @Override
+ public void addContext(String aContext) {
+ super.addContext(aContext);
+ for (Component component : _components) {
+ component.addContext(aContext);
+ }
+ }
+
+ /**
+ * Validates the components together to check that there are no required
+ * services not in the required list and no services in the provided list
+ * that cannot be provided. Also logs a warning in case of superfluous
+ * requirements.
+ *
+ * @throws SystemAssemblyException
+ * in case of any validation problems.
+ */
+ public void validate() {
+ doStartOptionalDryRun(null, true);
+ }
+
+ /**
+ * Seal the container, meaning that no further components or interfaces may
+ * be added.
+ */
+ public void seal() {
+ _sealed = true;
+ }
+
+ /**
+ * Checks if the container is sealed.
+ *
+ * @return True iff the container is sealed.
+ */
+ public boolean isSealed() {
+ return _sealed;
+ }
+
+ /**
+ * Utility method to start with an empty external scope. This is useful for
+ * top-level containers which are not part of another container.
+ *
+ * @return Scope.
+ */
+ public Scope start() {
+ Scope scope = new DefaultScope(getProvidedInterfaces());
+ return super.start(scope);
+ }
+
+ @Override
+ protected Scope doStart(Scope aExternalScope) {
+ checkSealed();
+ validate();
+ Scope scope = new DefaultScope(getProvidedInterfaces(), aExternalScope);
+ ComponentGraph graph = doStartOptionalDryRun(scope, false);
+ exposeProvidedInterfaces(graph, aExternalScope, scope);
+ seal();
+ return scope;
+ }
+
+ private void exposeProvidedInterfaces(ComponentGraph aGraph, Scope aExternalScope,
+ Scope aInternalScope) {
+ for (Pair<ProvidedInterface,ProvidedInterface> mapping:
+ aGraph.findExternalProvidedInterfaceMapping()) {
+ Object svc = aInternalScope.getInterfaceImplementation(mapping.getSecond(), Object.class);
+ addInterface(mapping.getFirst(), svc, aExternalScope);
+ }
+ }
+
+ private ComponentGraph doStartOptionalDryRun(Scope aScope, boolean aDryRun) {
+ ComponentGraph graph = createComponentGraph();
+ graph.validate();
+ if (!aDryRun) {
+ graph.link();
+ }
+
+ LOG.info("Starting '" + getQualifiedName() + "'");
+
+ List<Component> started = new ArrayList<Component>();
+ for (Component component : _components) {
+ try {
+ // Start the service.
+ if (!aDryRun) {
+ Object runtime = component.start(aScope);
+ aScope.addRuntime(component, runtime);
+ started.add(component);
+ }
+ } catch (SystemAssemblyException e) {
+ throw e;
+ } catch (RuntimeException e) {
+ LOG.error(getQualifiedName() + ": could not start '"
+ + component.getQualifiedName() + "'", e);
+ stopAlreadyStartedComponents(started, aScope);
+ throw e;
+ }
+ }
+ return graph;
+ }
+
+ private ComponentGraph createComponentGraph() {
+ ComponentGraph graph = new ComponentGraph();
+ for (RequiredInterface req : getRequiredInterfaces()) {
+ graph.addRequiredInterface(req);
+ }
+ for (Component comp : _components) {
+ graph.addComponent(comp);
+ }
+ for (ProvidedInterface prov: getProvidedInterfaces()) {
+ graph.addProvidedInterface(prov);
+ }
+
+ graph.addRestriction(_restriction);
+ return graph;
+ }
+
+ private void stopAlreadyStartedComponents(List<Component> aStarted,
+ Scope aScope) {
+ // an exception occurred, stop the successfully started
+ // components
+ for (int i = aStarted.size() - 1; i >= 0; i--) {
+ try {
+ Component component = aStarted.get(i);
+ aStarted.get(i).stop(aScope.getRuntime(component));
+ } catch (Throwable t) {
+ LOG.error(getQualifiedName() + ": error stopping "
+ + aStarted.get(i).getQualifiedName());
+ }
+ }
+ }
+
+ @Override
+ protected void doStop(Scope aScope) {
+ for (int i = _components.size() - 1; i >= 0; i--) {
+ Component component = _components.get(i);
+ Object runtime = aScope.getRuntime(component);
+ component.stop(runtime);
+ }
+ }
+
+ private void checkSealed() {
+ if (_sealed) {
+ throw new SystemAssemblyException("Container is sealed");
+ }
+ }
+}
git://wamblee.org / utils / blobdiff