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Allow use of '&' prefix to access factory bean in SpEL

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Prior to this change SpEL did not have an syntactic
construct enabling easy access to a FactoryBean. With this
change it is now possible to use &foo in an expression when
the factory bean should be returned.

Issue: SPR-9511
This commit is contained in:
Andy Clement
2016-01-21 16:14:16 -08:00
parent 415b2763ce
commit a12f23936c
9 changed files with 207 additions and 19 deletions
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9
spring-expression/src/main/java/org/springframework/expression/BeanResolver.java
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@@ -1,5 +1,5 @@
/*
* Copyright 2002-2012 the original author or authors.
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -18,7 +18,9 @@ package org.springframework.expression;
/**
* A bean resolver can be registered with the evaluation context
* and will kick in for {@code @myBeanName} still expressions.
* and will kick in for {@code @myBeanName} and {@code &myBeanName} expressions.
* The <tt>&</tt> variant syntax allows access to the factory bean where
* relevant.
*
* @author Andy Clement
* @since 3.0.3
@@ -26,7 +28,8 @@ package org.springframework.expression;
public interface BeanResolver {
/**
* Look up the named bean and return it.
* Look up the named bean and return it. If attempting to access a factory
* bean the name will have a <tt>&</tt> prefix.
* @param context the current evaluation context
* @param beanName the name of the bean to lookup
* @return an object representing the bean

4
spring-expression/src/main/java/org/springframework/expression/spel/SpelMessage.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2014 the original author or authors.
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -214,7 +214,7 @@ public enum SpelMessage {
"A problem occurred when trying to resolve bean ''{0}'':''{1}''"),
INVALID_BEAN_REFERENCE(Kind.ERROR, 1059,
"@ can only be followed by an identifier or a quoted name"),
"@ or & can only be followed by an identifier or a quoted name"),
TYPE_NAME_EXPECTED_FOR_ARRAY_CONSTRUCTION(Kind.ERROR, 1060,
"Expected the type of the new array to be specified as a String but found ''{0}''"),

12
spring-expression/src/main/java/org/springframework/expression/spel/ast/BeanReference.java
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@@ -25,12 +25,15 @@ import org.springframework.expression.spel.SpelEvaluationException;
import org.springframework.expression.spel.SpelMessage;
/**
* Represents a bean reference to a type, for example "@foo" or "@'foo.bar'"
*
* Represents a bean reference to a type, for example <tt>@foo</tt> or <tt>@'foo.bar'</tt>.
* For a FactoryBean the syntax <tt>&foo</tt> can be used to access the factory itself.
*
* @author Andy Clement
*/
public class BeanReference extends SpelNodeImpl {
private final static String FACTORY_BEAN_PREFIX = "&";
private final String beanName;
@@ -59,7 +62,10 @@ public class BeanReference extends SpelNodeImpl {
@Override
public String toStringAST() {
StringBuilder sb = new StringBuilder("@");
StringBuilder sb = new StringBuilder();
if (!this.beanName.startsWith(FACTORY_BEAN_PREFIX)) {
sb.append("@");
}
if (!this.beanName.contains(".")) {
sb.append(this.beanName);
}

13
spring-expression/src/main/java/org/springframework/expression/spel/standard/InternalSpelExpressionParser.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2015 the original author or authors.
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -525,7 +525,7 @@ class InternalSpelExpressionParser extends TemplateAwareExpressionParser {
// parse: @beanname @'bean.name'
// quoted if dotted
private boolean maybeEatBeanReference() {
if (peekToken(TokenKind.BEAN_REF)) {
if (peekToken(TokenKind.BEAN_REF) || peekToken(TokenKind.FACTORY_BEAN_REF)) {
Token beanRefToken = nextToken();
Token beanNameToken = null;
String beanName = null;
@@ -543,7 +543,14 @@ class InternalSpelExpressionParser extends TemplateAwareExpressionParser {
SpelMessage.INVALID_BEAN_REFERENCE);
}
BeanReference beanReference = new BeanReference(toPos(beanNameToken) ,beanName);
BeanReference beanReference = null;
if (beanRefToken.getKind() == TokenKind.FACTORY_BEAN_REF) {
String beanNameString = new StringBuilder().append(TokenKind.FACTORY_BEAN_REF.tokenChars).append(beanName).toString();
beanReference = new BeanReference(toPos(beanRefToken.startPos,beanNameToken.endPos),beanNameString);
}
else {
beanReference = new BeanReference(toPos(beanNameToken) ,beanName);
}
this.constructedNodes.push(beanReference);
return true;
}

4
spring-expression/src/main/java/org/springframework/expression/spel/standard/TokenKind.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2014 the original author or authors.
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -112,6 +112,8 @@ enum TokenKind {
BEAN_REF("@"),
FACTORY_BEAN_REF("&"),
SYMBOLIC_OR("||"),
SYMBOLIC_AND("&&"),

12
spring-expression/src/main/java/org/springframework/expression/spel/standard/Tokenizer.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2013 the original author or authors.
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -182,12 +182,12 @@ class Tokenizer {
}
break;
case '&':
if (!isTwoCharToken(TokenKind.SYMBOLIC_AND)) {
throw new InternalParseException(new SpelParseException(
this.expressionString, this.pos, SpelMessage.MISSING_CHARACTER,
"&"));
if (isTwoCharToken(TokenKind.SYMBOLIC_AND)) {
pushPairToken(TokenKind.SYMBOLIC_AND);
}
else {
pushCharToken(TokenKind.FACTORY_BEAN_REF);
}
pushPairToken(TokenKind.SYMBOLIC_AND);
break;
case '|':
if (!isTwoCharToken(TokenKind.SYMBOLIC_OR)) {

31
spring-expression/src/test/java/org/springframework/expression/spel/SpelReproTests.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright 2002-2015 the original author or authors.
* Copyright 2002-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -718,6 +718,9 @@ public class SpelReproTests extends AbstractExpressionTests {
else if (beanName.equals("foo.bar")) {
return "trouble";
}
else if (beanName.equals("&foo")) {
return "foo factory";
}
else if (beanName.equals("goo")) {
throw new AccessException("DONT ASK ME ABOUT GOO");
}
@@ -1950,6 +1953,32 @@ public class SpelReproTests extends AbstractExpressionTests {
res = parser.parseExpression("#root.![values()]").getValue(context, List.class);
assertEquals("[[test12, test11], [test22, test21]]", res.toString());
}
@Test
public void AccessingFactoryBean_spr9511() {
StandardEvaluationContext context = new StandardEvaluationContext();
context.setBeanResolver(new MyBeanResolver());
Expression expr = new SpelExpressionParser().parseRaw("@foo");
assertEquals("custard", expr.getValue(context));
expr = new SpelExpressionParser().parseRaw("&foo");
assertEquals("foo factory",expr.getValue(context));
try {
expr = new SpelExpressionParser().parseRaw("&@foo");
fail("Illegal syntax, error expected");
} catch (SpelParseException spe) {
assertEquals(SpelMessage.INVALID_BEAN_REFERENCE,spe.getMessageCode());
assertEquals(0,spe.getPosition());
}
try {
expr = new SpelExpressionParser().parseRaw("@&foo");
fail("Illegal syntax, error expected");
} catch (SpelParseException spe) {
assertEquals(SpelMessage.INVALID_BEAN_REFERENCE,spe.getMessageCode());
assertEquals(0,spe.getPosition());
}
}
@Test
public void SPR12035() {