public class IllegalInstantiationCheck extends AbstractCheck
Checks for illegal instantiations where a factory method is preferred.
Rationale: Depending on the project, for some classes it might be preferable to create instances through factory methods rather than calling the constructor.
A simple example is the java.lang.Boolean class, to save memory and CPU cycles it is preferable to use the predefined constants TRUE and FALSE. Constructor invocations should be replaced by calls to Boolean.valueOf().
Some extremely performance sensitive projects may require the use of factory methods for other classes as well, to enforce the usage of number caches or object pools.
Limitations: It is currently not possible to specify array classes.
An example of how to configure the check is:
<module name="IllegalInstantiation"/>
Modifier and Type | Field and Description |
---|---|
private java.util.Set<java.lang.String> |
classNames
The class names defined in the file.
|
private java.util.Set<java.lang.String> |
illegalClasses
Set of fully qualified class names.
|
private java.util.Set<FullIdent> |
imports
The imports for the file.
|
private java.util.Set<DetailAST> |
instantiations
The instantiations in the file.
|
private static java.lang.String |
JAVA_LANG
java.lang package as string. |
static java.lang.String |
MSG_KEY
A key is pointing to the warning message text in "messages.properties"
file.
|
private java.lang.String |
pkgName
Name of the package.
|
Constructor and Description |
---|
IllegalInstantiationCheck() |
Modifier and Type | Method and Description |
---|---|
void |
beginTree(DetailAST rootAST)
Called before the starting to process a tree.
|
private java.lang.String |
checkImportStatements(java.lang.String className)
Check import statements.
|
void |
finishTree(DetailAST rootAST)
Called after finished processing a tree.
|
int[] |
getAcceptableTokens()
The configurable token set.
|
int[] |
getDefaultTokens()
Returns the default token a check is interested in.
|
private java.lang.String |
getIllegalInstantiation(java.lang.String className)
Checks illegal instantiations.
|
int[] |
getRequiredTokens()
The tokens that this check must be registered for.
|
private boolean |
isSamePackage(java.lang.String className)
Is class of the same package.
|
private boolean |
isSamePackage(java.lang.String className,
int pkgNameLen,
java.lang.String illegal)
Check that type is of the same package.
|
private boolean |
isStandardClass(java.lang.String className,
java.lang.String illegal)
Is Standard Class.
|
private void |
postProcessLiteralNew(DetailAST newTokenAst)
Processes one of the collected "new" tokens when walking tree
has finished.
|
private void |
processClassDef(DetailAST ast)
Collects classes defined in the source file.
|
private void |
processImport(DetailAST ast)
Perform processing for an import token.
|
private void |
processLiteralNew(DetailAST ast)
Collects a "new" token.
|
private void |
processPackageDef(DetailAST ast)
Perform processing for an package token.
|
void |
setClasses(java.lang.String... names)
Sets the classes that are illegal to instantiate.
|
void |
visitToken(DetailAST ast)
Called to process a token.
|
destroy, getClassLoader, getFileContents, getLine, getLines, getTabWidth, getTokenNames, init, isCommentNodesRequired, leaveToken, log, log, setClassLoader, setFileContents, setMessages, setTabWidth, setTokens
getCustomMessages, getId, getMessageBundle, getSeverity, getSeverityLevel, log, setId, setSeverity
configure, contextualize, finishLocalSetup, getConfiguration, setupChild
public static final java.lang.String MSG_KEY
private static final java.lang.String JAVA_LANG
java.lang
package as string.private final java.util.Set<FullIdent> imports
private final java.util.Set<java.lang.String> classNames
private final java.util.Set<DetailAST> instantiations
private java.util.Set<java.lang.String> illegalClasses
private java.lang.String pkgName
public int[] getDefaultTokens()
AbstractCheck
getDefaultTokens
in class AbstractCheck
TokenTypes
public int[] getAcceptableTokens()
AbstractCheck
getAcceptableTokens
in class AbstractCheck
TokenTypes
public int[] getRequiredTokens()
AbstractCheck
getRequiredTokens
in class AbstractCheck
TokenTypes
public void beginTree(DetailAST rootAST)
AbstractCheck
beginTree
in class AbstractCheck
rootAST
- the root of the treepublic void visitToken(DetailAST ast)
AbstractCheck
visitToken
in class AbstractCheck
ast
- the token to processpublic void finishTree(DetailAST rootAST)
AbstractCheck
finishTree
in class AbstractCheck
rootAST
- the root of the treeprivate void processClassDef(DetailAST ast)
ast
- the class def token.private void processImport(DetailAST ast)
ast
- the import tokenprivate void processPackageDef(DetailAST ast)
ast
- the package tokenprivate void processLiteralNew(DetailAST ast)
ast
- the "new" tokenprivate void postProcessLiteralNew(DetailAST newTokenAst)
newTokenAst
- the "new" token.private java.lang.String getIllegalInstantiation(java.lang.String className)
className
- instantiated class, may or may not be qualifiedprivate java.lang.String checkImportStatements(java.lang.String className)
className
- name of the classprivate boolean isSamePackage(java.lang.String className, int pkgNameLen, java.lang.String illegal)
className
- class namepkgNameLen
- package nameillegal
- illegal valueprivate boolean isSamePackage(java.lang.String className)
className
- class nameprivate boolean isStandardClass(java.lang.String className, java.lang.String illegal)
className
- class nameillegal
- illegal valuepublic void setClasses(java.lang.String... names)
names
- a comma separate list of class names