SEC-1971: Allow injection of ExpressionParser in AbstractSecurityExpressionHandler

Author: rwinch

core/src/main/java/org/springframework/security/access/expression/AbstractSecurityExpressionHandler.java

@@ -11,6 +11,7 @@
 import org.springframework.security.access.PermissionEvaluator;
 import org.springframework.security.access.hierarchicalroles.RoleHierarchy;
 import org.springframework.security.core.Authentication;
+import org.springframework.util.Assert;
 
 /**
  * Base implementation of the facade which isolates Spring Security's requirements for evaluating security expressions
@@ -20,7 +21,7 @@
  * @since 3.1
  */
 public abstract class AbstractSecurityExpressionHandler<T> implements SecurityExpressionHandler<T>, ApplicationContextAware {
-    private final ExpressionParser expressionParser = new SpelExpressionParser();
+    private ExpressionParser expressionParser = new SpelExpressionParser();
     private BeanResolver br;
     private RoleHierarchy roleHierarchy;
     private PermissionEvaluator permissionEvaluator = new DenyAllPermissionEvaluator();
@@ -29,6 +30,11 @@ public final ExpressionParser getExpressionParser() {
         return expressionParser;
     }
 
+    public final void setExpressionParser(ExpressionParser expressionParser) {
+        Assert.notNull(expressionParser, "expressionParser cannot be null");
+        this.expressionParser = expressionParser;
+    }
+
     /**
      * Invokes the internal template methods to create {@code StandardEvaluationContext} and {@code SecurityExpressionRoot}
      * objects.

core/src/test/java/org/springframework/security/access/expression/AbstractSecurityExpressionHandlerTests.java

@@ -3,16 +3,15 @@
 import static org.junit.Assert.assertTrue;
 import static org.mockito.Mockito.mock;
 
-import org.junit.*;
-import org.springframework.context.ApplicationContext;
+import org.junit.Before;
+import org.junit.Test;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.expression.Expression;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.security.core.Authentication;
 
-import java.util.*;
-
 /**
  * @author Luke Taylor
  */
@@ -36,6 +35,18 @@ public void beanNamesAreCorrectlyResolved() throws Exception {
         Expression expression = handler.getExpressionParser().parseExpression("@number10.compareTo(@number20) < 0");
         assertTrue((Boolean) expression.getValue(handler.createEvaluationContext(mock(Authentication.class), new Object())));
     }
+
+    @Test(expected=IllegalArgumentException.class)
+    public void setExpressionParserNull() {
+        handler.setExpressionParser(null);
+    }
+
+    @Test
+    public void setExpressionParser() {
+        SpelExpressionParser parser = new SpelExpressionParser();
+        handler.setExpressionParser(parser);
+        assertTrue(parser == handler.getExpressionParser());
+    }
 }
 
 @Configuration