Miscellaneous Checks |
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EqualsHashCodeDescriptionChecks that classes that override equals() also override hashCode(). Rationale: The contract of equals() and hashCode() requires that equal objects have the same hashCode. Hence, whenever you override equals() you must override hashCode() to ensure that your class can be used in collections that are hash based. ExampleTo configure the check: <module name="EqualsHashCode"/> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleGenericIllegalRegexpDescriptionA generic check for code problems - the user can search for any pattern. This is similar to a recursive grep, only that it's integrated in checkstyle. Rationale: This check can be used to prototype checks and to find common bad practice such as calling ex.printStacktrace(), System.out.println(), System.exit(), etc. Properties
ExampleTo configure the check for calls to System.out.println: <module name="GenericIllegalRegexp"> <property name="format" value="System\.out\.println"/> </module> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleHiddenFieldDescriptionChecks that a local variable or a parameter does not shadow a field that is defined in the same class. Properties
ExamplesTo configure the check: <module name="HiddenField"/> To configure the check so that it checks local variables but not parameters: <module name="HiddenField"> <property name="tokens" value="VARIABLE_DEF"/> </module> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleIllegalInstantiationDescriptionChecks 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. In order 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. NotesThere is a limitation that it is currently not possible to specify array classes.
ExampleTo configure the check: <module name="IllegalInstantiation"/> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleInnerAssignmentDescriptionChecks for assignments in subexpressions, such as in String s = Integer.toString(i = 2);. Rationale: With the exception of for iterators, all assignments should occur in their own toplevel statement to increase readability. With inner assignments like the above it is difficult to see all places where a variable is set. Properties
ExamplesTo configure the check: <module name="InnerAssignment"/> To configure the check for only =, +=, and -= operators: <module name="InnerAssignment"> <property name="tokens" value="ASSIGN,PLUS_ASSIGN,MINUS_ASSIGN"/> </module> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleSimplifyBooleanExpressionDescriptionChecks for overly complicated boolean expressions. Currently finds code like if (b == true), b || true, !false, etc. Rationale: Complex boolean logic makes code hard to understand and maintain. ExampleTo configure the check: <module name="SimplifyBooleanExpression"/> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleSimplifyBooleanReturnDescriptionChecks for overly complicated boolean return statements. For example the following code if (valid()) return false; else return true; could be written as return !valid(); The Idea for this Check has been shamelessly stolen from the equivalent PMD rule. ExampleTo configure the check: <module name="SimplifyBooleanReturn"/> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleTodoCommentDescriptionA check for TODO: comments. Actually it is a generic regular expression matcher on Java comments. To check for other patterns in Java comments, set property format. Properties
NotesUsing TODO: comments is a great way to keep track of tasks that need to be done. Having them reported by Checkstyle makes it very hard to forget about them. ExamplesTo configure the check: <module name="TodoComment"/> To configure the check for comments that contain WARNING: <module name="TodoComment"> <property name="format" value="WARNING"/> </module> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleTranslationDescriptionA FileSetCheck that ensures the correct translation of code by checking property files for consistency regarding their keys. Two property files describing one and the same context are consistent if they contain the same keys. Consider the following properties file in the same directory: #messages.properties hello=Hello cancel=Cancel #messages_de.properties hell=Hallo ok=OK The Translation check will find the typo in the german hello key, the missing ok key in the default resource file and the missing cancel key in the german resource file: messages_de.properties: Key 'hello' missing. messages_de.properties: Key 'cancel' missing. messages.properties: Key 'hell' missing. messages.properties: Key 'ok' missing. Properties
ExampleTo configure the check: <module name="Translation"/> Packagecom.puppycrawl.tools.checkstyle.checks Parent ModuleUpperEllDescriptionChecks that long constants are defined with an upper ell. That is ' L' and not 'l'. This is in accordance to the Java Language Specification, Section 3.10.1. Rationale: The letter l looks a lot like 1. ExamplesTo configure the check: <module name="UpperEll"/> Packagecom.puppycrawl.tools.checkstyle.checks Parent Module |
Copyright © 2002 Oliver Burn. All rights Reserved.