jakarta.enterprise.lang.model.declarations.DeclarationInfo Maven / Gradle / Ivy

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/*
 * Copyright 2021, Red Hat, Inc., and individual contributors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package jakarta.enterprise.lang.model.declarations;

import jakarta.enterprise.lang.model.AnnotationTarget;
import jakarta.enterprise.lang.model.types.Type;

/**
 * A declaration is an element of a program source code.
 * Declarations are:
 *
 * 
 * {@linkplain PackageInfo packages}
 * {@linkplain ClassInfo classes}, including interfaces, enums, annotations, and records
 * {@linkplain FieldInfo fields}
 * {@linkplain MethodInfo methods}, including constructors
 * {@linkplain ParameterInfo method parameters}, including constructor parameters
 * {@linkplain RecordComponentInfo record components}
 * 
 *
 * @since 4.0
 */
public interface DeclarationInfo extends AnnotationTarget {
    @Override
    default boolean isDeclaration() {
        return true;
    }

    @Override
    default boolean isType() {
        return false;
    }

    @Override
    default DeclarationInfo asDeclaration() {
        return this;
    }

    @Override
    default Type asType() {
        throw new IllegalStateException("Not a type");
    }

    /**
     * The declaration kind: package, class, method, parameter, field, record component.
     */
    enum Kind {
        /**
         * Package
         */
        PACKAGE,
        /**
         * Class, interface, enum, annotation, or record
         */
        CLASS,
        /**
         * Method or constructor
         */
        METHOD,
        /**
         * Method parameter or constructor parameter
         */
        PARAMETER,
        /**
         * Field
         */
        FIELD,
        /**
         * Record component
         */
        RECORD_COMPONENT,
    }

    /**
     * Returns the {@linkplain Kind kind} of this declaration.
     *
     * @return the kind of this declaration
     */
    Kind kind();

    /**
     * Returns whether this declaration is a {@linkplain PackageInfo package}.
     *
     * @return {@code true} if this is a package, {@code false} otherwise
     */
    default boolean isPackage() {
        return kind() == Kind.PACKAGE;
    }

    /**
     * Returns whether this declaration is a {@linkplain ClassInfo class}.
     *
     * @return {@code true} if this is a class, {@code false} otherwise
     */
    default boolean isClass() {
        return kind() == Kind.CLASS;
    }

    /**
     * Returns whether this declaration is a {@linkplain MethodInfo method}.
     *
     * @return {@code true} if this is a method, {@code false} otherwise
     */
    default boolean isMethod() {
        return kind() == Kind.METHOD;
    }

    /**
     * Returns whether this declaration is a {@linkplain ParameterInfo method parameter}.
     *
     * @return {@code true} if this is a parameter, {@code false} otherwise
     */
    default boolean isParameter() {
        return kind() == Kind.PARAMETER;
    }

    /**
     * Returns whether this declaration is a {@linkplain FieldInfo field}.
     *
     * @return {@code true} if this is a field, {@code false} otherwise
     */
    default boolean isField() {
        return kind() == Kind.FIELD;
    }

    /**
     * Returns whether this declaration is a {@linkplain RecordComponentInfo record component}.
     *
     * @return {@code true} if this is a record component, {@code false} otherwise
     */
    default boolean isRecordComponent() {
        return kind() == Kind.RECORD_COMPONENT;
    }

    /**
     * Returns this declaration as a {@linkplain PackageInfo package}.
     *
     * @return this package, never {@code null}
     * @throws IllegalStateException if {@link #isPackage()} returns {@code false}
     */
    default PackageInfo asPackage() {
        throw new IllegalStateException("Not a package");
    }

    /**
     * Returns this declaration as a {@linkplain ClassInfo class}.
     *
     * @return this class, never {@code null}
     * @throws IllegalStateException if {@link #isClass()} returns {@code false}
     */
    default ClassInfo asClass() {
        throw new IllegalStateException("Not a class");
    }

    /**
     * Returns this declaration as a {@linkplain MethodInfo method}.
     *
     * @return this method, never {@code null}
     * @throws IllegalStateException if {@link #isMethod()} returns {@code false}
     */
    default MethodInfo asMethod() {
        throw new IllegalStateException("Not a method");
    }

    /**
     * Returns this declaration as a {@linkplain ParameterInfo method parameter}.
     *
     * @return this parameter, never {@code null}
     * @throws IllegalStateException if {@link #isParameter()} returns {@code false}
     */
    default ParameterInfo asParameter() {
        throw new IllegalStateException("Not a parameter");
    }

    /**
     * Returns this declaration as a {@linkplain FieldInfo field}.
     *
     * @return this field, never {@code null}
     * @throws IllegalStateException if {@link #isField()} returns {@code false}
     */
    default FieldInfo asField() {
        throw new IllegalStateException("Not a field");
    }

    /**
     * Returns this declaration as a {@linkplain RecordComponentInfo record component}.
     *
     * @return this record component, never {@code null}
     * @throws IllegalStateException if {@link #isRecordComponent()} returns {@code false}
     */
    default RecordComponentInfo asRecordComponent() {
        throw new IllegalStateException("Not a record component");
    }
}