wamblee.org Git - utils/blob - system/general/src/main/java/org/wamblee/system/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;
  17
  18 import java.util.ArrayList;
  19 import java.util.Arrays;
  20 import java.util.List;
  21
  22 import org.apache.commons.logging.Log;
  23 import org.apache.commons.logging.LogFactory;
  24
  25 import sun.util.LocaleServiceProviderPool.LocalizedObjectGetter;
  26
  27 /**
  28  * Composite system consisting of multiple subsystems.
  29  *
  30  * @author Erik Brakkee
  31  */
  32 public class Container extends AbstractComponent {
  33
  34         private static final Log LOG = LogFactory.getLog(Container.class);
  35
  36         private Component[] _systems;
  37
  38         /**
  39          * Construcst the composite system.
  40          * @param aName Name of the system.
  41          * @param aRegistry Service registry.
  42          * @param aSystems Subsystems.
  43          * @param aProvided Provided services of the system.
  44          * @param aRequired Required services by the system.
  45          */
  46         public Container(String aName, Component[] aSystems,
  47                         ProvidedInterface[] aProvided, RequiredInterface[] aRequired) {
  48                 super(aName, aProvided, aRequired);
  49                 _systems = aSystems;
  50                 validate(aRequired);
  51         }
  52
  53         /**
  54          * Validates the subsystems together to check that there are
  55          * no required services not in the required list and
  56          * no services in the provided list that cannot be provided.
  57          * Also logs a warning in case of superfluous requirements.
  58          */
  59         private void validate(RequiredInterface[] aRequired) {
  60                 List<ProvidedInterface> provided = new ArrayList<ProvidedInterface>();
  61                 for (Component system : _systems) {
  62                         provided.addAll(Arrays.asList(system.getProvidedServices()));
  63                 }
  64
  65                 List<RequiredInterface> required = new ArrayList<RequiredInterface>();
  66                 for (Component system : _systems) {
  67                         required.addAll(Arrays.asList(system.getRequiredServices()));
  68                 }
  69
  70                 for (ProvidedInterface service : getProvidedServices()) {
  71                         if (!(provided.contains(service))) {
  72                                 throw new SystemAssemblyException(getName() + ": Service '" + service
  73                                                 + "' is not provided by any of the subsystems");
  74                         }
  75                 }
  76
  77                 for (RequiredInterface service : getRequiredServices()) {
  78                         if (!(required.contains(service))) {
  79                                 info("Service '"
  80                                                 + service
  81                                                 + "' indicated as required is not actually required by any of the subsystems");
  82                         }
  83                 }
  84
  85                 List<RequiredInterface> reallyRequired = new ArrayList<RequiredInterface>(
  86                                 required);
  87                 // Compute all required interfaces that are not provided
  88                 for (ProvidedInterface service : provided) {
  89                         List<RequiredInterface> fulfilled =
  90                                 Arrays.asList(SystemAssembler.filterRequiredServices(service,
  91                                         reallyRequired));
  92                         reallyRequired.removeAll(fulfilled);
  93                 }
  94                 // Now the remaining interfaces should be covered by the required
  95                 // list.
  96                 reallyRequired.removeAll(Arrays.asList(aRequired));
  97
  98                 String missingRequired = "";
  99                 for (RequiredInterface service: reallyRequired) {
 100                         missingRequired += service + "\n";
 101                 }
 102                 if ( missingRequired.length() > 0 ) {
 103                         throw new SystemAssemblyException(getName() + ": missing required services\n" + missingRequired);
 104                 }
 105         }
 106
 107         @Override
 108         protected void doStart(String aContext) {
 109                 List<ProvidedInterface> provided = new ArrayList<ProvidedInterface>();
 110
 111                 // all interfaces from the required list of this container are
 112                 // provided to the components inside it.
 113                 RequiredInterface[] required = getRequiredServices();
 114                 for (RequiredInterface intf: required) {
 115                     ProvidedInterface provider = intf.getProvider();
 116                     if ( provider == null ) {
 117                         throw new SystemAssemblyException(aContext + ": required interface '" + intf +"' is not provided");
 118                     }
 119                         provided.add(intf.getProvider());
 120                 }
 121
 122                 SystemAssembler assembler = new SystemAssembler( _systems,
 123                                 provided.toArray(new ProvidedInterface[0]));
 124                 assembler.start();
 125         }
 126
 127         @Override
 128         protected void doStop() {
 129                 for (int i = _systems.length-1; i >= 0; i--) {
 130                         _systems[i].stop();
 131                 }
 132         }
 133
 134         private void info(String aMsg) {
 135                 LOG.info(getName() + ": " + aMsg);
 136         }
 137
 138 }