edu.hm.hafner.analysis.parser.checkstyle.config_modifier.xml Maven / Gradle / Ivy
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<title>Modifiers</title>
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</section>
<section name="InterfaceMemberImpliedModifier">
<p>Since Checkstyle 8.12</p>
<subsection name="Description" id="InterfaceMemberImpliedModifier_Description">
<p>
Checks for implicit modifiers on interface members and nested types.
</p>
<p>
This check is effectively the opposite of
<a href="#RedundantModifier">RedundantModifier</a>.
It checks the modifiers on interface members, ensuring that certain
modifiers are explicitly specified even though they are actually redundant.
</p>
<p>
Methods in interfaces are <code>public</code> by default, however from Java 9
they can also be <code>private</code>. This check provides the ability to enforce
that <code>public</code> is explicitly coded and not implicitly added by the compiler.
</p>
<p>
From Java 8, there are three types of methods in interfaces - static methods
marked with <code>static</code>, default methods marked with <code>default</code> and
abstract methods which do not have to be marked with anything.
From Java 9, there are also private methods marked with <code>private</code>.
This check provides the ability to enforce that <code>abstract</code> is explicitly
coded and not implicitly added by the compiler.
</p>
<p>
Fields in interfaces are always <code>public static final</code> and as such the
compiler does not require these modifiers. This check provides the ability to
enforce that these modifiers are explicitly coded and not implicitly added by
the compiler.
</p>
<p>
Nested types within an interface are always <code>public static</code> and as such the
compiler does not require the <code>public static</code> modifiers. This check provides
the ability to enforce that the <code>public</code> and <code>static</code> modifiers
are explicitly coded and not implicitly added by the compiler.
</p>
<source>
public interface AddressFactory {
// check enforces code contains "public static final"
public static final String UNKNOWN = "Unknown";
String OTHER = "Other"; // violation
// check enforces code contains "public" or "private"
public static AddressFactory instance();
// check enforces code contains "public abstract"
public abstract Address createAddress(String addressLine, String city);
List<Address> findAddresses(String city); // violation
// check enforces default methods are explicitly declared "public"
public default Address createAddress(String city) {
return createAddress(UNKNOWN, city);
}
default Address createOtherAddress() { // violation
return createAddress(OTHER, OTHER);
}
}
</source>
<p>
Rationale for this check:
Methods, fields and nested types are treated differently depending on whether
they are part of an interface or part of a class. For example, by default methods
are package-scoped on classes, but public in interfaces. However, from Java 8 onwards,
interfaces have changed to be much more like abstract classes.
Interfaces now have static and instance methods with code. Developers should not have
to remember which modifiers are required and which are implied.
This check allows the simpler alternative approach to be adopted where the
implied modifiers must always be coded explicitly.
</p>
</subsection>
<subsection name="Properties" id="InterfaceMemberImpliedModifier_Properties">
<table>
<tr>
<th>name</th>
<th>description</th>
<th>type</th>
<th>default value</th>
<th>since</th>
</tr>
<tr>
<td>violateImpliedPublicField</td>
<td>
Control whether to enforce that <code>public</code> is explicitly coded
on interface fields.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
<tr>
<td>violateImpliedStaticField</td>
<td>
Control whether to enforce that <code>static</code> is explicitly coded
on interface fields.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
<tr>
<td>violateImpliedFinalField</td>
<td>
Control whether to enforce that <code>final</code> is explicitly coded
on interface fields.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
<tr>
<td>violateImpliedPublicMethod</td>
<td>
Control whether to enforce that <code>public</code> is explicitly coded
on interface methods.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
<tr>
<td>violateImpliedAbstractMethod</td>
<td>
Control whether to enforce that <code>abstract</code> is explicitly coded
on interface methods.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
<tr>
<td>violateImpliedPublicNested</td>
<td>
Control whether to enforce that <code>public</code> is explicitly coded
on interface nested types.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
<tr>
<td>violateImpliedStaticNested</td>
<td>
Control whether to enforce that <code>static</code> is explicitly coded
on interface nested types.</td>
<td><a href="property_types.html#boolean">Boolean</a></td>
<td><code>true</code></td>
<td>8.12</td>
</tr>
</table>
</subsection>
<subsection name="Examples" id="InterfaceMemberImpliedModifier_Examples">
<p>
This example checks that all implicit modifiers on methods, fields and nested
types are explicitly specified in interfaces.
</p>
<p>
Configuration:
</p>
<source>
<module name="InterfaceMemberImpliedModifier"/>
</source>
<p>
Code:
</p>
<source>
public interface AddressFactory {
public static final String UNKNOWN = "Unknown"; // valid
String OTHER = "Other"; // violation
public static AddressFactory instance(); // valid
public abstract Address createAddress(String addressLine, String city); // valid
List<Address> findAddresses(String city); // violation
interface Address { // violation
String getCity(); // violation
}
}
</source>
<p>
This example checks that all implicit modifiers on methods and fields are
explicitly specified, but nested types do not need to be.
</p>
<p>
Configuration:
</p>
<source>
<module name="InterfaceMemberImpliedModifier">
<property name="violateImpliedPublicNested" value="false"/>
<property name="violateImpliedStaticNested" value="false"/>
</module>
</source>
<p>
Code:
</p>
<source>
public interface RoadFeature {
String STOP = "Stop"; // violation
enum Lights { // valid because of configured properties
RED, YELLOW, GREEN;
}
}
</source>
</subsection>
<subsection name="Example of Usage" id="InterfaceMemberImpliedModifier_Example_of_Usage">
<ul>
<li>
<a href="https://github.com/search?q=path%3Aconfig+filename%3Acheckstyle_checks.xml+repo%3Acheckstyle%2Fcheckstyle+InterfaceMemberImpliedModifier">
Checkstyle Style</a>
</li>
</ul>
</subsection>
<subsection name="Error Messages" id="InterfaceMemberImpliedModifier_Error_Messages">
<ul>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fmodifier+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22interface.implied.modifier%22">
interface.implied.modifier</a>
</li>
</ul>
<p>
All messages can be customized if the default message doesn't suit you.
Please <a href="config.html#Custom_messages">see the documentation</a> to learn how to.
</p>
</subsection>
<subsection name="Package" id="InterfaceMemberImpliedModifier_Package">
<p> com.puppycrawl.tools.checkstyle.checks.modifier </p>
</subsection>
<subsection name="Parent Module" id="InterfaceMemberImpliedModifier_Parent_Module">
<p>
<a href="config.html#TreeWalker">TreeWalker</a>
</p>
</subsection>
</section>
<section name="ModifierOrder">
<subsection name="Description" id="ModifierOrder_Description">
<p>Since Checkstyle 3.0</p>
<p>
Checks that the order of modifiers conforms to the suggestions in
the <a
href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-8.html">Java
Language specification, sections 8.1.1, 8.3.1, 8.4.3</a> and <a
href="https://docs.oracle.com/javase/specs/jls/se8/html/jls-9.html">
9.4</a>. The correct order is:
</p>
<ol>
<li>
<code>public</code>
</li>
<li>
<code>protected</code>
</li>
<li>
<code>private</code>
</li>
<li>
<code>abstract</code>
</li>
<li>
<code>default</code>
</li>
<li>
<code>static</code>
</li>
<li>
<code>final</code>
</li>
<li>
<code>transient</code>
</li>
<li>
<code>volatile</code>
</li>
<li>
<code>synchronized</code>
</li>
<li>
<code>native</code>
</li>
<li>
<code>strictfp</code>
</li>
</ol>
<p>
ATTENTION: We skip
<a href="https://www.oracle.com/technetwork/articles/java/ma14-architect-annotations-2177655.html">
type annotations</a> from validation.
</p>
</subsection>
<subsection name="Examples" id="ModifierOrder_Examples">
<p> To configure the check: </p>
<source>
<module name="ModifierOrder"/>
</source>
</subsection>
<subsection name="Example of Usage" id="ModifierOrder_Example_of_Usage">
<ul>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources+filename%3Agoogle_checks.xml+repo%3Acheckstyle%2Fcheckstyle+ModifierOrder">
Google Style</a>
</li>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources+filename%3Asun_checks.xml+repo%3Acheckstyle%2Fcheckstyle+ModifierOrder">
Sun Style</a>
</li>
<li>
<a href="https://github.com/search?q=path%3Aconfig+filename%3Acheckstyle_checks.xml+repo%3Acheckstyle%2Fcheckstyle+ModifierOrder">
Checkstyle Style</a>
</li>
</ul>
</subsection>
<subsection name="Error Messages" id="ModifierOrder_Error_Messages">
<ul>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fmodifier+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22annotation.order%22">
annotation.order</a>
</li>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fmodifier+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22mod.order%22">
mod.order</a>
</li>
</ul>
<p>
All messages can be customized if the default message doesn't suit you.
Please <a href="config.html#Custom_messages">see the documentation</a> to learn how to.
</p>
</subsection>
<subsection name="Package" id="ModifierOrder_Package">
<p> com.puppycrawl.tools.checkstyle.checks.modifier </p>
</subsection>
<subsection name="Parent Module" id="ModifierOrder_Parent_Module">
<p>
<a href="config.html#TreeWalker">TreeWalker</a>
</p>
</subsection>
</section>
<section name="RedundantModifier">
<subsection name="Description" id="RedundantModifier_Description">
<p>Since Checkstyle 3.0</p>
<p>
Checks for redundant modifiers in:
</p>
<ol>
<li>Interface and annotation definitions.</li>
<li>Final modifier on methods of final and anonymous classes.</li>
<li>
Inner <code>interface</code> declarations that are declared
as <code>static</code>.
</li>
<li>Class constructors.</li>
<li>
Nested <code>enum</code> definitions that are declared
as <code>static</code>.
</li>
</ol>
<p>
Rationale: The Java Language Specification strongly
discourages the usage of <code>public</code> and <code>abstract</code> for method
declarations in interface definitions as a matter of style.
</p>
<p>
Interfaces by definition are abstract so the <code>abstract</code>
modifier on the interface is redundant.
</p>
<p>
Classes inside of interfaces by definition are public and static,
so the <code>public</code> and <code>static</code> modifiers
on the inner classes are redundant. On the other hand, classes
inside of interfaces can be abstract or non abstract.
So, <code>abstract</code> modifier is allowed.
</p>
<p>
Fields in interfaces and annotations are automatically
public, static and final, so these modifiers are redundant as
well.
</p>
<p>
As annotations are a form of interface, their fields are also
automatically public, static and final just as their
annotation fields are automatically public and abstract.
</p>
<p>
Enums by definition are static implicit subclasses of java.lang.Enum<E>.
So, the <code>static</code> modifier on the enums is redundant. In addition,
if enum is inside of interface, <code>public</code> modifier is also redundant.
</p>
<p>
Enums can also contain abstract methods and methods which can be overridden by the
declared enumeration fields.
See the following example:
</p>
<source>
public enum EnumClass {
FIELD_1,
FIELD_2 {
@Override
public final void method1() {} // violation expected
};
public void method1() {}
public final void method2() {} // no violation expected
}
</source>
<p>
Since these methods can be overridden in these situations, the final methods are not
marked as redundant even though they can't be extended by other classes/enums.
</p>
<p>
Nested <code>enum</code> types are always static by default.
</p>
<p>
Final classes by definition cannot be extended so the <code>final</code>
modifier on the method of a final class is redundant.
</p>
<p>
Public modifier for constructors in non-public non-protected classes
is always obsolete:
</p>
<source>
public class PublicClass {
public PublicClass() {} // OK
}
class PackagePrivateClass {
public PackagePrivateClass() {} // violation expected
}
</source>
<p>There is no violation in the following example,
because removing public modifier from ProtectedInnerClass
constructor will make this code not compiling:
</p>
<source>
package a;
public class ClassExample {
protected class ProtectedInnerClass {
public ProtectedInnerClass () {}
}
}
package b;
import a.ClassExample;
public class ClassExtending extends ClassExample {
ProtectedInnerClass pc = new ProtectedInnerClass();
}
</source>
</subsection>
<subsection name="Properties" id="RedundantModifier_Properties">
<table>
<tr>
<th>name</th>
<th>description</th>
<th>type</th>
<th>default value</th>
<th>since</th>
</tr>
<tr>
<td>tokens</td>
<td>tokens to check</td>
<td>
subset of tokens
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
METHOD_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
VARIABLE_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
ANNOTATION_FIELD_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
INTERFACE_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CTOR_DEF">
CTOR_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
CLASS_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
ENUM_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RESOURCE">
RESOURCE</a>.
</td>
<td>
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#METHOD_DEF">
METHOD_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#VARIABLE_DEF">
VARIABLE_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ANNOTATION_FIELD_DEF">
ANNOTATION_FIELD_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#INTERFACE_DEF">
INTERFACE_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CTOR_DEF">
CTOR_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#CLASS_DEF">
CLASS_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#ENUM_DEF">
ENUM_DEF</a>,
<a href="apidocs/com/puppycrawl/tools/checkstyle/api/TokenTypes.html#RESOURCE">
RESOURCE</a>.
</td>
<td>3.0</td>
</tr>
</table>
</subsection>
<subsection name="Examples" id="RedundantModifier_Examples">
<p> To configure the check: </p>
<source>
<module name="RedundantModifier"/>
</source>
<p>
To configure the check to check only methods and not variables:
</p>
<source>
<module name="RedundantModifier">
<property name="tokens" value="METHOD_DEF"/>
</module>
</source>
</subsection>
<subsection name="Example of Usage" id="RedundantModifier_Example_of_Usage">
<ul>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources+filename%3Asun_checks.xml+repo%3Acheckstyle%2Fcheckstyle+RedundantModifier">
Sun Style</a>
</li>
<li>
<a href="https://github.com/search?q=path%3Aconfig+filename%3Acheckstyle_checks.xml+repo%3Acheckstyle%2Fcheckstyle+RedundantModifier">
Checkstyle Style</a>
</li>
</ul>
</subsection>
<subsection name="Error Messages" id="RedundantModifier_Error_Messages">
<ul>
<li>
<a href="https://github.com/search?q=path%3Asrc%2Fmain%2Fresources%2Fcom%2Fpuppycrawl%2Ftools%2Fcheckstyle%2Fchecks%2Fmodifier+filename%3Amessages*.properties+repo%3Acheckstyle%2Fcheckstyle+%22redundantModifier%22">
redundantModifier</a>
</li>
</ul>
<p>
All messages can be customized if the default message doesn't suit you.
Please <a href="config.html#Custom_messages">see the documentation</a> to learn how to.
</p>
</subsection>
<subsection name="Package" id="RedundantModifier_Package">
<p> com.puppycrawl.tools.checkstyle.checks.modifier </p>
</subsection>
<subsection name="Parent Module" id="RedundantModifier_Parent_Module">
<p>
<a href="config.html#TreeWalker">TreeWalker</a>
</p>
</subsection>
</section>
</body>
</document>
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