Java tutorial
/* * Copyright 2015 Open Networking Laboratory * * 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.onosproject.cfg.impl; import com.google.common.collect.ImmutableSet; import com.google.common.collect.Maps; import org.apache.felix.scr.annotations.Activate; import org.apache.felix.scr.annotations.Component; import org.apache.felix.scr.annotations.Deactivate; import org.apache.felix.scr.annotations.Reference; import org.apache.felix.scr.annotations.ReferenceCardinality; import org.apache.felix.scr.annotations.Service; import org.onlab.util.AbstractAccumulator; import org.onlab.util.Accumulator; import org.onlab.util.SharedExecutors; import org.onosproject.cfg.ComponentConfigEvent; import org.onosproject.cfg.ComponentConfigService; import org.onosproject.cfg.ComponentConfigStore; import org.onosproject.cfg.ComponentConfigStoreDelegate; import org.onosproject.cfg.ConfigProperty; import org.osgi.service.cm.Configuration; import org.osgi.service.cm.ConfigurationAdmin; import org.slf4j.Logger; import java.io.IOException; import java.io.InputStream; import java.util.Dictionary; import java.util.Enumeration; import java.util.HashSet; import java.util.Hashtable; import java.util.List; import java.util.Map; import java.util.Set; import static com.google.common.base.Preconditions.checkArgument; import static com.google.common.base.Preconditions.checkNotNull; import static org.onosproject.security.AppGuard.checkPermission; import static org.slf4j.LoggerFactory.getLogger; import static org.onosproject.security.AppPermission.Type.*; /** * Implementation of the centralized component configuration service. */ @Component(immediate = true) @Service public class ComponentConfigManager implements ComponentConfigService { private static final String COMPONENT_NULL = "Component name cannot be null"; private static final String PROPERTY_NULL = "Property name cannot be null"; private static final String COMPONENT_MISSING = "Component %s is not registered"; private static final String PROPERTY_MISSING = "Property %s does not exist for %s"; //Symbolic constants for use with the accumulator private static final int MAX_ITEMS = 100; private static final int MAX_BATCH_MILLIS = 1000; private static final int MAX_IDLE_MILLIS = 250; private static final String RESOURCE_EXT = ".cfgdef"; private final Logger log = getLogger(getClass()); private final ComponentConfigStoreDelegate delegate = new InternalStoreDelegate(); private final InternalAccumulator accumulator = new InternalAccumulator(); @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) protected ComponentConfigStore store; @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY) protected ConfigurationAdmin cfgAdmin; // Locally maintained catalog of definitions. private final Map<String, Map<String, ConfigProperty>> properties = Maps.newConcurrentMap(); @Activate public void activate() { store.setDelegate(delegate); log.info("Started"); } @Deactivate public void deactivate() { store.unsetDelegate(delegate); log.info("Stopped"); } @Override public Set<String> getComponentNames() { checkPermission(CONFIG_READ); return ImmutableSet.copyOf(properties.keySet()); } @Override public void registerProperties(Class<?> componentClass) { checkPermission(CONFIG_WRITE); String componentName = componentClass.getName(); String resourceName = componentClass.getSimpleName() + RESOURCE_EXT; try (InputStream ris = componentClass.getResourceAsStream(resourceName)) { checkArgument(ris != null, "Property definitions not found at resource %s", resourceName); // Read the definitions Set<ConfigProperty> defs = ConfigPropertyDefinitions.read(ris); // Produce a new map of the properties and register it. Map<String, ConfigProperty> map = Maps.newConcurrentMap(); defs.forEach(p -> map.put(p.name(), p)); properties.put(componentName, map); loadExistingValues(componentName); } catch (IOException e) { log.error("Unable to read property definitions from resource " + resourceName, e); } } @Override public void unregisterProperties(Class<?> componentClass, boolean clear) { checkPermission(CONFIG_WRITE); String componentName = componentClass.getName(); checkNotNull(componentName, COMPONENT_NULL); Map<String, ConfigProperty> cps = properties.remove(componentName); if (clear && cps != null) { cps.keySet().forEach(name -> store.unsetProperty(componentName, name)); clearExistingValues(componentName); } } // Clears any existing values that may have been set. private void clearExistingValues(String componentName) { triggerUpdate(componentName); } @Override public Set<ConfigProperty> getProperties(String componentName) { checkPermission(CONFIG_READ); Map<String, ConfigProperty> map = properties.get(componentName); return map != null ? ImmutableSet.copyOf(map.values()) : null; } @Override public void setProperty(String componentName, String name, String value) { checkPermission(CONFIG_WRITE); checkNotNull(componentName, COMPONENT_NULL); checkNotNull(name, PROPERTY_NULL); checkArgument(properties.containsKey(componentName), COMPONENT_MISSING, componentName); checkArgument(properties.get(componentName).containsKey(name), PROPERTY_MISSING, name, componentName); store.setProperty(componentName, name, value); } @Override public void preSetProperty(String componentName, String name, String value) { checkPermission(CONFIG_WRITE); checkNotNull(componentName, COMPONENT_NULL); checkNotNull(name, PROPERTY_NULL); store.setProperty(componentName, name, value); } @Override public void unsetProperty(String componentName, String name) { checkPermission(CONFIG_WRITE); checkNotNull(componentName, COMPONENT_NULL); checkNotNull(name, PROPERTY_NULL); checkArgument(properties.containsKey(componentName), COMPONENT_MISSING, componentName); checkArgument(properties.get(componentName).containsKey(name), PROPERTY_MISSING, name, componentName); store.unsetProperty(componentName, name); } private class InternalStoreDelegate implements ComponentConfigStoreDelegate { @Override public void notify(ComponentConfigEvent event) { String componentName = event.subject(); String name = event.name(); String value = event.value(); switch (event.type()) { case PROPERTY_SET: set(componentName, name, value); break; case PROPERTY_UNSET: reset(componentName, name); break; default: break; } } } // Buffers multiple subsequent configuration updates into one notification. private class InternalAccumulator extends AbstractAccumulator<String> implements Accumulator<String> { protected InternalAccumulator() { super(SharedExecutors.getTimer(), MAX_ITEMS, MAX_BATCH_MILLIS, MAX_IDLE_MILLIS); } @Override public void processItems(List<String> items) { // Conversion to set removes duplicates Set<String> componentSet = new HashSet<>(items); componentSet.forEach(ComponentConfigManager.this::triggerUpdate); } } // Locates the property in the component map and replaces it with an // updated copy. private void set(String componentName, String name, String value) { Map<String, ConfigProperty> map = properties.get(componentName); if (map != null) { ConfigProperty prop = map.get(name); if (prop != null) { map.put(name, ConfigProperty.setProperty(prop, value)); accumulator.add(componentName); return; } } log.warn("Unable to set non-existent property {} for component {}", name, componentName); } // Locates the property in the component map and replaces it with an // reset copy. private void reset(String componentName, String name) { Map<String, ConfigProperty> map = properties.get(componentName); if (map != null) { ConfigProperty prop = map.get(name); if (prop != null) { map.put(name, ConfigProperty.resetProperty(prop)); accumulator.add(componentName); return; } log.warn("Unable to reset non-existent property {} for component {}", name, componentName); } } // Loads existing property values that may have been set. private void loadExistingValues(String componentName) { try { Configuration cfg = cfgAdmin.getConfiguration(componentName, null); Map<String, ConfigProperty> map = properties.get(componentName); Dictionary<String, Object> props = cfg.getProperties(); if (props != null) { Enumeration<String> it = props.keys(); while (it.hasMoreElements()) { String name = it.nextElement(); ConfigProperty p = map.get(name); if (p != null) { map.put(name, ConfigProperty.setProperty(p, (String) props.get(name))); } } } } catch (IOException e) { log.error("Unable to get configuration for " + componentName, e); } } // FIXME: This should be a slightly deferred execution to allow changing // values just once per component when a number of updates arrive shortly // after each other. private void triggerUpdate(String componentName) { try { Configuration cfg = cfgAdmin.getConfiguration(componentName, null); Map<String, ConfigProperty> map = properties.get(componentName); Dictionary<String, Object> props = new Hashtable<>(); map.values().forEach(p -> props.put(p.name(), p.value())); cfg.update(props); } catch (IOException e) { log.warn("Unable to update configuration for " + componentName, e); } } }