src/java.compiler/share/classes/javax/annotation/processing/Messager.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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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
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 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
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 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package javax.annotation.processing;

import javax.tools.Diagnostic;
import javax.lang.model.element.*;

/**
 * A {@code Messager} provides the way for an annotation processor to
 * report error messages, warnings, and other notices.  Elements,
 * annotations, and annotation values can be passed to provide a
 * location hint for the message.  However, such location hints may be
 * unavailable or only approximate.
 *
 * <p>Printing a message with an {@linkplain
 * javax.tools.Diagnostic.Kind#ERROR error kind} will {@linkplain
 * RoundEnvironment#errorRaised raise an error}.
 *
 * @apiNote
 * The messages &quot;printed&quot; by methods in this
 * interface may or may not appear as textual output to a location
 * like {@link System#out} or {@link System#err}.  Implementations may
 * choose to present this information in a different fashion, such as
 * messages in a window.
 *
 * @see ProcessingEnvironment#getLocale
 * @since 1.6
 */
public interface Messager {
    /**
     * Prints a message of the specified kind.
     *
     * @param kind the kind of message
     * @param msg  the message, or an empty string if none
     */
    void printMessage(Diagnostic.Kind kind, CharSequence msg);

    /**
     * Prints a message of the specified kind at the location of the
     * element.
     *
     * @param kind the kind of message
     * @param msg  the message, or an empty string if none
     * @param e    the element to use as a position hint
     */
    void printMessage(Diagnostic.Kind kind, CharSequence msg, Element e);

    /**
     * Prints a message of the specified kind at the location of the
     * annotation mirror of the annotated element.
     *
     * @param kind the kind of message
     * @param msg  the message, or an empty string if none
     * @param e    the annotated element
     * @param a    the annotation to use as a position hint
     */
    void printMessage(Diagnostic.Kind kind, CharSequence msg, Element e, AnnotationMirror a);

    /**
     * Prints a message of the specified kind at the location of the
     * annotation value inside the annotation mirror of the annotated
     * element.
     *
     * @param kind the kind of message
     * @param msg  the message, or an empty string if none
     * @param e    the annotated element
     * @param a    the annotation containing the annotation value
     * @param v    the annotation value to use as a position hint
     */
    void printMessage(Diagnostic.Kind kind,
                      CharSequence msg,
                      Element e,
                      AnnotationMirror a,
                      AnnotationValue v);
    /**
     * Prints an error.
     *
     * @implSpec
     * The default implementation is equivalent to {@code
     * printMessage(Diagnostic.Kind.ERROR, msg)}.
     *
     * @param msg  the message, or an empty string if none
     * @since 18
     */
    default void printError(CharSequence msg) {
        printMessage(Diagnostic.Kind.ERROR, msg);
    }

    /**
     * Prints an error at the location of the element.
     *
     * @implSpec
     * The default implementation is equivalent to {@code
     * printMessage(Diagnostic.Kind.ERROR, msg, e)}.
     *
     * @param msg  the message, or an empty string if none
     * @param e    the element to use as a position hint
     * @since 18
     */
    default void printError(CharSequence msg, Element e) {
        printMessage(Diagnostic.Kind.ERROR, msg, e);
    }

    /**
     * Prints a warning.
     *
     * @implSpec
     * The default implementation is equivalent to {@code
     * printMessage(Diagnostic.Kind.WARNING, msg)}.
     *
     * @param msg  the message, or an empty string if none
     * @since 18
     */
    default void printWarning(CharSequence msg) {
        printMessage(Diagnostic.Kind.WARNING, msg);
    }

    /**
     * Prints a warning at the location of the element.
     *
     * @implSpec
     * The default implementation is equivalent to {@code
     * printMessage(Diagnostic.Kind.WARNING, msg, e)}.
     *
     * @param msg  the message, or an empty string if none
     * @param e    the element to use as a position hint
     * @since 18
     */
    default void printWarning(CharSequence msg, Element e) {
        printMessage(Diagnostic.Kind.WARNING, msg, e);
    }

    /**
     * Prints a note.
     *
     * @implSpec
     * The default implementation is equivalent to {@code
     * printMessage(Diagnostic.Kind.NOTE, msg)}.
     *
     * @param msg  the message, or an empty string if none
     * @since 18
     */
    default void printNote(CharSequence msg) {
        printMessage(Diagnostic.Kind.NOTE, msg);
    }

    /**
     * Prints a note at the location of the element.
     *
     * @implSpec
     * The default implementation is equivalent to {@code
     * printMessage(Diagnostic.Kind.NOTE, msg, e)}.
     *
     * @param msg  the message, or an empty string if none
     * @param e    the element to use as a position hint
     * @since 18
     */
    default void printNote(CharSequence msg, Element e) {
        printMessage(Diagnostic.Kind.NOTE, msg, e);
    }
}