runtime/org.argeo.slc.support.simple/src/main/java/org/argeo/slc/core/execution/ExecutionContext.java

   1 package org.argeo.slc.core.execution;
   2
   3 import java.util.HashMap;
   4 import java.util.Map;
   5 import java.util.Stack;
   6 import java.util.UUID;
   7
   8 import org.apache.commons.logging.Log;
   9 import org.apache.commons.logging.LogFactory;
  10 import org.argeo.slc.SlcException;
  11 import org.argeo.slc.execution.ExecutionFlow;
  12 import org.argeo.slc.execution.ExecutionSpecAttribute;
  13 import org.argeo.slc.process.SlcExecution;
  14 import org.springframework.beans.factory.ObjectFactory;
  15
  16 public class ExecutionContext {
  17         private final static Log log = LogFactory.getLog(ExecutionContext.class);
  18
  19         private final static ThreadLocal<ExecutionContext> executionContext = new ThreadLocal<ExecutionContext>();
  20
  21         private final Stack<ExecutionFlowRuntime> stack = new Stack<ExecutionFlowRuntime>();
  22
  23         // TODO: make it thread safe?
  24         private final Map<String, Object> variables = new HashMap<String, Object>();
  25
  26         private final String uuid = UUID.randomUUID().toString();
  27
  28         public static Map<String, Object> getVariables() {
  29                 if (executionContext.get() == null)
  30                         return null;
  31                 return executionContext.get().variables;
  32         }
  33
  34         public static ExecutionContext getCurrent() {
  35                 return executionContext.get();
  36         }
  37
  38         public static String getExecutionUuid() {
  39                 if (executionContext.get() == null)
  40                         return null;
  41                 return executionContext.get().getUuid();
  42         }
  43
  44         public static void registerExecutionContext(ExecutionContext context) {
  45                 if (executionContext.get() != null)
  46                         throw new SlcException("Context #" + executionContext.get().uuid
  47                                         + " already registered.");
  48                 executionContext.set(context);
  49         }
  50
  51         public static void enterFlow(ExecutionFlow executionFlow) {
  52                 Stack<ExecutionFlowRuntime> stack = executionContext.get().stack;
  53
  54                 ExecutionFlowRuntime runtime = new ExecutionFlowRuntime(executionFlow);
  55                 stack.push(runtime);
  56
  57                 if (log.isDebugEnabled())
  58                         log.debug(depthSpaces(stack.size()) + "=> " + executionFlow + " #"
  59                                         + getCurrentStackUuid() + ", depth=" + stack.size());
  60
  61                 Map<String, ExecutionSpecAttribute> specAttrs = executionFlow
  62                                 .getExecutionSpec().getAttributes();
  63                 for (String key : specAttrs.keySet()) {
  64                         //ExecutionSpecAttribute esa = specAttrs.get(key);
  65                         if (executionFlow.isSetAsParameter(key)) {
  66                                 runtime.getLocalVariables().put(key,
  67                                                 executionFlow.getParameter(key));
  68                                 if (log.isTraceEnabled())
  69                                         log.trace(depthSpaces(stack.size()) + "Add '" + key
  70                                                         + "' as local variable.");
  71                         }
  72                 }
  73
  74         }
  75
  76         public static Object getVariable(String key) {
  77                 Object obj = getWithCheck().findVariable(key);
  78                 if (obj == null)
  79                         throw new SlcException("Variable '" + key + "' not found.");
  80                 return obj;
  81         }
  82
  83         protected Object findVariable(String key) {
  84                 Object obj = null;
  85                 for (int i = stack.size() - 1; i >= 0; i--) {
  86                         if (stack.get(i).getLocalVariables().containsKey(key)) {
  87                                 obj = stack.get(i).getLocalVariables().get(key);
  88                                 break;
  89                         }
  90                 }
  91
  92                 // Look into global execution variables
  93                 if (obj == null) {
  94                         if (variables.containsKey(key))
  95                                 obj = variables.get(key);
  96                 }
  97
  98                 return obj;
  99         }
 100
 101         private static String depthSpaces(int depth) {
 102                 StringBuffer buf = new StringBuffer(depth * 2);
 103                 for (int i = 0; i < depth; i++)
 104                         buf.append("  ");
 105                 return buf.toString();
 106         }
 107
 108         public static void leaveFlow(ExecutionFlow executionFlow) {
 109                 Stack<ExecutionFlowRuntime> stack = executionContext.get().stack;
 110                 if (log.isDebugEnabled())
 111                         log.debug(depthSpaces(stack.size()) + "<= " + executionFlow + " #"
 112                                         + getCurrentStackUuid() + ", depth=" + stack.size());
 113
 114                 ExecutionFlowRuntime leftEf = stack.pop();
 115                 if (!leftEf.getExecutionFlow().getName()
 116                                 .equals(executionFlow.getName()))
 117                         throw new SlcException("Asked to leave " + executionFlow
 118                                         + " but last is " + leftEf);
 119
 120                 leftEf.getScopedObjects().clear();
 121                 leftEf.getLocalVariables().clear();
 122
 123         }
 124
 125         public static String getCurrentStackUuid() {
 126                 return getWithCheck().stack.peek().uuid;
 127         }
 128
 129         // public static ExecutionFlow getCurrentFlow() {
 130         // return getWithCheck().stack.peek().executionFlow;
 131         // }
 132
 133         public static Boolean isExecuting() {
 134                 return executionContext.get() != null;
 135         }
 136
 137         protected static ExecutionContext getWithCheck() {
 138                 if (executionContext.get() == null)
 139                         throw new SlcException("No execution context");
 140                 return executionContext.get();
 141         }
 142
 143         public static Object findOrAddScopedObject(String name,
 144                         ObjectFactory objectFactory) {
 145                 ExecutionContext executionContext = getWithCheck();
 146                 Object obj = executionContext.findScopedObject(name);
 147                 if (obj == null) {
 148                         obj = objectFactory.getObject();
 149                         executionContext.stack.peek().getScopedObjects().put(name, obj);
 150                 }
 151                 return obj;
 152         }
 153
 154         /** return null if not found */
 155         protected Object findScopedObject(String key) {
 156                 Object obj = null;
 157                 for (int i = stack.size() - 1; i >= 0; i--) {
 158                         if (stack.get(i).getScopedObjects().containsKey(key)) {
 159                                 obj = stack.get(i).getScopedObjects().get(key);
 160                                 break;
 161                         }
 162                 }
 163                 return obj;
 164         }
 165
 166         public String getUuid() {
 167                 return uuid;
 168         }
 169
 170         private static class ExecutionFlowRuntime {
 171                 private final ExecutionFlow executionFlow;
 172                 private final Map<String, Object> scopedObjects = new HashMap<String, Object>();
 173                 private final Map<String, Object> localVariables = new HashMap<String, Object>();
 174                 private final String uuid = UUID.randomUUID().toString();
 175
 176                 public ExecutionFlowRuntime(ExecutionFlow executionFlow) {
 177                         this.executionFlow = executionFlow;
 178                 }
 179
 180                 public ExecutionFlow getExecutionFlow() {
 181                         return executionFlow;
 182                 }
 183
 184                 public Map<String, Object> getScopedObjects() {
 185                         return scopedObjects;
 186                 }
 187
 188                 public String getUuid() {
 189                         return uuid;
 190                 }
 191
 192                 public Map<String, Object> getLocalVariables() {
 193                         return localVariables;
 194                 }
 195
 196         }
 197 }