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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
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*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
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* 2 along with this work; if not, write to the Free Software Foundation,
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package javax.lang.model.util;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.EnumSet;
import java.util.ArrayList;
import java.util.LinkedHashSet;
import javax.lang.model.element.*;
import javax.lang.model.element.ModuleElement.Directive;
import javax.lang.model.element.ModuleElement.DirectiveKind;
import javax.lang.model.element.ModuleElement.ExportsDirective;
import javax.lang.model.element.ModuleElement.OpensDirective;
import javax.lang.model.element.ModuleElement.ProvidesDirective;
import javax.lang.model.element.ModuleElement.RequiresDirective;
import javax.lang.model.element.ModuleElement.UsesDirective;
/**
* Filters for selecting just the elements of interest from a
* collection of elements. The returned sets and lists are new
* collections and do use the argument as a backing store. The
* methods in this class do not make any attempts to guard against
* concurrent modifications of the arguments. The returned sets and
* lists are mutable but unsafe for concurrent access. A returned set
* has the same iteration order as the argument set to a method.
*
*
If iterables and sets containing {@code null} are passed as
* arguments to methods in this class, a {@code NullPointerException}
* will be thrown.
*
*
Note that a static import statement can make the text of
* calls to the methods in this class more concise; for example:
*
*
* import static javax.lang.model.util.ElementFilter.*;
* ...
* {@code List} fs = fieldsIn(someClass.getEnclosedElements());
*
*
* @author Joseph D. Darcy
* @author Scott Seligman
* @author Peter von der Ahé
* @author Martin Buchholz
* @since 1.6
*/
public class ElementFilter {
private ElementFilter() {} // Do not instantiate.
private static final Set CONSTRUCTOR_KIND =
Collections.unmodifiableSet(EnumSet.of(ElementKind.CONSTRUCTOR));
private static final Set FIELD_KINDS =
Collections.unmodifiableSet(EnumSet.of(ElementKind.FIELD,
ElementKind.ENUM_CONSTANT));
private static final Set METHOD_KIND =
Collections.unmodifiableSet(EnumSet.of(ElementKind.METHOD));
private static final Set PACKAGE_KIND =
Collections.unmodifiableSet(EnumSet.of(ElementKind.PACKAGE));
private static final Set MODULE_KIND =
Collections.unmodifiableSet(EnumSet.of(ElementKind.MODULE));
private static final Set TYPE_KINDS =
Collections.unmodifiableSet(EnumSet.of(ElementKind.CLASS,
ElementKind.ENUM,
ElementKind.INTERFACE,
ElementKind.ANNOTATION_TYPE));
/**
* Returns a list of fields in {@code elements}.
* @return a list of fields in {@code elements}
* @param elements the elements to filter
*/
public static List
fieldsIn(Iterable extends Element> elements) {
return listFilter(elements, FIELD_KINDS, VariableElement.class);
}
/**
* Returns a set of fields in {@code elements}.
* @return a set of fields in {@code elements}
* @param elements the elements to filter
*/
public static Set
fieldsIn(Set extends Element> elements) {
return setFilter(elements, FIELD_KINDS, VariableElement.class);
}
/**
* Returns a list of constructors in {@code elements}.
* @return a list of constructors in {@code elements}
* @param elements the elements to filter
*/
public static List
constructorsIn(Iterable extends Element> elements) {
return listFilter(elements, CONSTRUCTOR_KIND, ExecutableElement.class);
}
/**
* Returns a set of constructors in {@code elements}.
* @return a set of constructors in {@code elements}
* @param elements the elements to filter
*/
public static Set
constructorsIn(Set extends Element> elements) {
return setFilter(elements, CONSTRUCTOR_KIND, ExecutableElement.class);
}
/**
* Returns a list of methods in {@code elements}.
* @return a list of methods in {@code elements}
* @param elements the elements to filter
*/
public static List
methodsIn(Iterable extends Element> elements) {
return listFilter(elements, METHOD_KIND, ExecutableElement.class);
}
/**
* Returns a set of methods in {@code elements}.
* @return a set of methods in {@code elements}
* @param elements the elements to filter
*/
public static Set
methodsIn(Set extends Element> elements) {
return setFilter(elements, METHOD_KIND, ExecutableElement.class);
}
/**
* Returns a list of types in {@code elements}.
* @return a list of types in {@code elements}
* @param elements the elements to filter
*/
public static List
typesIn(Iterable extends Element> elements) {
return listFilter(elements, TYPE_KINDS, TypeElement.class);
}
/**
* Returns a set of types in {@code elements}.
* @return a set of types in {@code elements}
* @param elements the elements to filter
*/
public static Set
typesIn(Set extends Element> elements) {
return setFilter(elements, TYPE_KINDS, TypeElement.class);
}
/**
* Returns a list of packages in {@code elements}.
* @return a list of packages in {@code elements}
* @param elements the elements to filter
*/
public static List
packagesIn(Iterable extends Element> elements) {
return listFilter(elements, PACKAGE_KIND, PackageElement.class);
}
/**
* Returns a set of packages in {@code elements}.
* @return a set of packages in {@code elements}
* @param elements the elements to filter
*/
public static Set
packagesIn(Set extends Element> elements) {
return setFilter(elements, PACKAGE_KIND, PackageElement.class);
}
/**
* Returns a list of modules in {@code elements}.
* @return a list of modules in {@code elements}
* @param elements the elements to filter
* @since 9
* @spec JPMS
*/
public static List
modulesIn(Iterable extends Element> elements) {
return listFilter(elements, MODULE_KIND, ModuleElement.class);
}
/**
* Returns a set of modules in {@code elements}.
* @return a set of modules in {@code elements}
* @param elements the elements to filter
* @since 9
* @spec JPMS
*/
public static Set
modulesIn(Set extends Element> elements) {
return setFilter(elements, MODULE_KIND, ModuleElement.class);
}
// Assumes targetKinds and E are sensible.
private static List listFilter(Iterable extends Element> elements,
Set targetKinds,
Class clazz) {
List list = new ArrayList<>();
for (Element e : elements) {
if (targetKinds.contains(e.getKind()))
list.add(clazz.cast(e));
}
return list;
}
// Assumes targetKinds and E are sensible.
private static Set setFilter(Set extends Element> elements,
Set targetKinds,
Class clazz) {
// Return set preserving iteration order of input set.
Set set = new LinkedHashSet<>();
for (Element e : elements) {
if (targetKinds.contains(e.getKind()))
set.add(clazz.cast(e));
}
return set;
}
/**
* Returns a list of {@code exports} directives in {@code directives}.
* @return a list of {@code exports} directives in {@code directives}
* @param directives the directives to filter
* @since 9
* @spec JPMS
*/
public static List
exportsIn(Iterable extends Directive> directives) {
return listFilter(directives, DirectiveKind.EXPORTS, ExportsDirective.class);
}
/**
* Returns a list of {@code opens} directives in {@code directives}.
* @return a list of {@code opens} directives in {@code directives}
* @param directives the directives to filter
* @since 9
*/
public static List
opensIn(Iterable extends Directive> directives) {
return listFilter(directives, DirectiveKind.OPENS, OpensDirective.class);
}
/**
* Returns a list of {@code provides} directives in {@code directives}.
* @return a list of {@code provides} directives in {@code directives}
* @param directives the directives to filter
* @since 9
* @spec JPMS
*/
public static List
providesIn(Iterable extends Directive> directives) {
return listFilter(directives, DirectiveKind.PROVIDES, ProvidesDirective.class);
}
/**
* Returns a list of {@code requires} directives in {@code directives}.
* @return a list of {@code requires} directives in {@code directives}
* @param directives the directives to filter
* @since 9
* @spec JPMS
*/
public static List
requiresIn(Iterable extends Directive> directives) {
return listFilter(directives, DirectiveKind.REQUIRES, RequiresDirective.class);
}
/**
* Returns a list of {@code uses} directives in {@code directives}.
* @return a list of {@code uses} directives in {@code directives}
* @param directives the directives to filter
* @since 9
* @spec JPMS
*/
public static List
usesIn(Iterable extends Directive> directives) {
return listFilter(directives, DirectiveKind.USES, UsesDirective.class);
}
// Assumes directiveKind and D are sensible.
private static List listFilter(Iterable extends Directive> directives,
DirectiveKind directiveKind,
Class clazz) {
List list = new ArrayList<>();
for (Directive d : directives) {
if (d.getKind() == directiveKind)
list.add(clazz.cast(d));
}
return list;
}
}