Add method in ExecutionContext to expose the internal map as read-only

Resolves #4004

Author: sjh836

spring-batch-core/src/main/java/org/springframework/batch/core/scope/context/JobContext.java

@@ -82,11 +82,7 @@ public Properties getSystemProperties() {
 	 * @return a map containing the items from the job {@link ExecutionContext}
 	 */
 	public Map<String, Object> getJobExecutionContext() {
-		Map<String, Object> result = new HashMap<>();
-		for (Entry<String, Object> entry : jobExecution.getExecutionContext().entrySet()) {
-			result.put(entry.getKey(), entry.getValue());
-		}
-		return Collections.unmodifiableMap(result);
+		return jobExecution.getExecutionContext().toMap();
 	}
 
 	/**

spring-batch-core/src/main/java/org/springframework/batch/core/scope/context/StepContext.java

@@ -111,22 +111,14 @@ public Properties getSystemProperties() {
 	 * @return a map containing the items from the step {@link ExecutionContext}
 	 */
 	public Map<String, Object> getStepExecutionContext() {
-		Map<String, Object> result = new HashMap<>();
-		for (Entry<String, Object> entry : stepExecution.getExecutionContext().entrySet()) {
-			result.put(entry.getKey(), entry.getValue());
-		}
-		return Collections.unmodifiableMap(result);
+		return stepExecution.getExecutionContext().toMap();
 	}
 
 	/**
 	 * @return a map containing the items from the job {@link ExecutionContext}
 	 */
 	public Map<String, Object> getJobExecutionContext() {
-		Map<String, Object> result = new HashMap<>();
-		for (Entry<String, Object> entry : stepExecution.getJobExecution().getExecutionContext().entrySet()) {
-			result.put(entry.getKey(), entry.getValue());
-		}
-		return Collections.unmodifiableMap(result);
+		return stepExecution.getJobExecution().getExecutionContext().toMap();
 	}
 
 	/**

spring-batch-infrastructure/src/main/java/org/springframework/batch/item/ExecutionContext.java

@@ -17,6 +17,7 @@
 package org.springframework.batch.item;
 
 import java.io.Serializable;
+import java.util.Collections;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
@@ -69,9 +70,7 @@ public ExecutionContext(ExecutionContext executionContext) {
 		if (executionContext == null) {
 			return;
 		}
-		for (Entry<String, Object> entry : executionContext.entrySet()) {
-			this.map.put(entry.getKey(), entry.getValue());
-		}
+		this.map.putAll(executionContext.toMap());
 	}
 
 	/**
@@ -293,11 +292,20 @@ public void clearDirtyFlag() {
 
 	/**
 	 * Returns the entry set containing the contents of this context.
-	 * @return A set representing the contents of the context
+	 * @return An unmodifiable set representing the contents of the context
 	 * @see java.util.Map#entrySet()
 	 */
 	public Set<Entry<String, Object>> entrySet() {
-		return this.map.entrySet();
+		return Collections.unmodifiableSet(this.map.entrySet());
+	}
+
+	/**
+	 * Returns the internal map as read-only.
+	 * @return An unmodifiable map containing all contents.
+	 * @see java.util.Map
+	 */
+	public Map<String, Object> toMap() {
+		return Collections.unmodifiableMap(this.map);
 	}
 
 	/**