From 25f732e06b09c99b04b0b43800b38eb2a33fc7df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ste=CC=81phane=20Nicoll?= <stephane@nicoll.net>
Date: Fri, 7 Dec 2012 18:43:18 +0100
Subject: [PATCH] delegating synchronization to ConcurrentHashMap instead of 
 dealing that ourselves.

---
 .../support/MapStepRegistry.java              | 38 ++++++++-----------
 1 file changed, 16 insertions(+), 22 deletions(-)

diff --git a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java
index a1cea6c93..8fb4348a0 100644
--- a/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java
+++ b/spring-batch-core/src/main/java/org/springframework/batch/core/configuration/support/MapStepRegistry.java
@@ -9,6 +9,8 @@ import org.springframework.util.Assert;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
 
 /**
  * Simple map-based implementation of {@link StepRegistry}. Access to the map is
@@ -19,7 +21,7 @@ import java.util.Map;
  */
 public class MapStepRegistry implements StepRegistry {
 
-    private final Map<String, Map<String, Step>> map = new HashMap<String, Map<String, Step>>();
+    private final ConcurrentMap<String, Map<String, Step>> map = new ConcurrentHashMap<String, Map<String, Step>>();
 
     public void register(String jobName, Collection<Step> steps) {
         Assert.notNull(jobName, "The job name cannot be null.");
@@ -27,38 +29,30 @@ public class MapStepRegistry implements StepRegistry {
 
         unregisterStepsFromJob(jobName);
 
-        synchronized (this.map) {
-            final Map<String, Step> jobSteps = new HashMap<String, Step>();
-            for (Step step : steps) {
-                jobSteps.put(step.getName(), step);
-            }
-
-            this.map.put(jobName, jobSteps);
+        final Map<String, Step> jobSteps = new HashMap<String, Step>();
+        for (Step step : steps) {
+            jobSteps.put(step.getName(), step);
         }
+        this.map.put(jobName, jobSteps);
     }
 
     public void unregisterStepsFromJob(String jobName) {
         Assert.notNull(jobName, "Job configuration must have a name.");
-        synchronized (map) {
-            map.remove(jobName);
-        }
+        map.remove(jobName);
     }
 
     public Step getStep(String jobName, String stepName) throws NoSuchJobException {
         Assert.notNull(jobName, "The job name cannot be null.");
         Assert.notNull(stepName, "The step name cannot be null.");
-
-        synchronized (map) {
-            if (!map.containsKey(jobName)) {
-                throw new NoSuchJobException("No job configuration with the name [" + jobName + "] was registered");
+        if (!map.containsKey(jobName)) {
+            throw new NoSuchJobException("No job configuration with the name [" + jobName + "] was registered");
+        } else {
+            final Map<String, Step> jobSteps = map.get(jobName);
+            if (jobSteps.containsKey(stepName)) {
+                return jobSteps.get(stepName);
             } else {
-                final Map<String, Step> jobSteps = map.get(jobName);
-                if (jobSteps.containsKey(stepName)) {
-                    return jobSteps.get(stepName);
-                } else {
-                    throw new NoSuchStepException("The step called [" + stepName + "] does not exist in the job [" +
-                            jobName + "]");
-                }
+                throw new NoSuchStepException("The step called [" + stepName + "] does not exist in the job [" +
+                        jobName + "]");
             }
         }
     }