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https://issues.apache.org/jira/browse/GROOVY-7921?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15441940#comment-15441940
]
Jochen Theodorou commented on GROOVY-7921:
------------------------------------------
Your category will return a new Integer, not mutate the old one. In that case
{code}
def static reset(Integer self, Integer value) {
self
}
{code}
would be already good enough. In Groovy you can in theory mutate the Integer,
but you really should not. The lower few Integer objects are cached (see
Integer.valueOf), so mutating one Integer here would have undesired side
effects elsewhere.
> not work to replace "this" with Category annotation
> ---------------------------------------------------
>
> Key: GROOVY-7921
> URL: https://issues.apache.org/jira/browse/GROOVY-7921
> Project: Groovy
> Issue Type: Bug
> Affects Versions: 2.4.7
> Environment: mac os x 10.10.5
> jdk 1.8.0_51
> Reporter: kyon_mm
>
> when I executed this code in GroovyConsole
> {code:java}
> @Category(Integer)
> class IntegerEx {
> def reset(int value) {
> this = value
> this
> }
> }
> use(IntegerEx){
> println (1 + 2).reset(1)
> }
> {code}
> Then, I get this exception log
> {code}
> Exception thrown
> BUG! exception in phase 'semantic analysis' in source unit 'ConsoleScript17'
> null
> at
> org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:935)
> at
> org.codehaus.groovy.control.CompilationUnit.doPhaseOperation(CompilationUnit.java:593)
> at
> org.codehaus.groovy.control.CompilationUnit.compile(CompilationUnit.java:542)
> at
> groovy.lang.GroovyClassLoader.doParseClass(GroovyClassLoader.java:298)
> at groovy.lang.GroovyClassLoader.parseClass(GroovyClassLoader.java:268)
> at groovy.lang.GroovyShell.parseClass(GroovyShell.java:688)
> at groovy.lang.GroovyShell.run(GroovyShell.java:517)
> at groovy.lang.GroovyShell.run(GroovyShell.java:497)
> at groovy.lang.GroovyShell.run(GroovyShell.java:170)
> at groovy.lang.GroovyShell$run$1.call(Unknown Source)
> at
> groovy.ui.Console$_runScriptImpl_closure16.doCall(Console.groovy:1005)
> at groovy.ui.Console$_runScriptImpl_closure16.doCall(Console.groovy)
> at sun.reflect.GeneratedMethodAccessor218.invoke(Unknown Source)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:497)
> at
> org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
> at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
> at
> org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:294)
> at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1024)
> at groovy.lang.Closure.call(Closure.java:414)
> at groovy.lang.Closure.call(Closure.java:408)
> at groovy.lang.Closure.run(Closure.java:495)
> at java.lang.Thread.run(Thread.java:745)
> Caused by: java.lang.NullPointerException
> at
> org.codehaus.groovy.classgen.VariableScopeVisitor.checkForFinal(VariableScopeVisitor.java:388)
> at
> org.codehaus.groovy.classgen.VariableScopeVisitor.checkFinalFieldAccess(VariableScopeVisitor.java:381)
> at
> org.codehaus.groovy.classgen.VariableScopeVisitor.visitBinaryExpression(VariableScopeVisitor.java:365)
> at
> org.codehaus.groovy.ast.expr.BinaryExpression.visit(BinaryExpression.java:51)
> at
> org.codehaus.groovy.ast.CodeVisitorSupport.visitExpressionStatement(CodeVisitorSupport.java:71)
> at
> org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitExpressionStatement(ClassCodeVisitorSupport.java:196)
> at
> org.codehaus.groovy.ast.stmt.ExpressionStatement.visit(ExpressionStatement.java:42)
> at
> org.codehaus.groovy.ast.CodeVisitorSupport.visitBlockStatement(CodeVisitorSupport.java:37)
> at
> org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitBlockStatement(ClassCodeVisitorSupport.java:166)
> at
> org.codehaus.groovy.classgen.VariableScopeVisitor.visitBlockStatement(VariableScopeVisitor.java:308)
> at
> org.codehaus.groovy.ast.stmt.BlockStatement.visit(BlockStatement.java:71)
> at
> org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClassCodeContainer(ClassCodeVisitorSupport.java:104)
> at
> org.codehaus.groovy.classgen.VariableScopeVisitor.visitConstructorOrMethod(VariableScopeVisitor.java:505)
> at
> org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitMethod(ClassCodeVisitorSupport.java:126)
> at org.codehaus.groovy.ast.ClassNode.visitContents(ClassNode.java:1078)
> at
> org.codehaus.groovy.ast.ClassCodeVisitorSupport.visitClass(ClassCodeVisitorSupport.java:53)
> at
> org.codehaus.groovy.classgen.VariableScopeVisitor.visitClass(VariableScopeVisitor.java:473)
> at
> org.codehaus.groovy.control.CompilationUnit$11.call(CompilationUnit.java:648)
> at
> org.codehaus.groovy.control.CompilationUnit.applyToSourceUnits(CompilationUnit.java:931)
> ... 22 more
> {code}
> Is this behavior groovy-language specification ?
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