public final class

Logger

extends java.lang.Object

 java.lang.Object

↳androidx.camera.viewfinder.internal.utils.Logger

Gradle dependencies

compile group: 'androidx.camera.viewfinder', name: 'viewfinder-view', version: '1.4.0-alpha08'

  • groupId: androidx.camera.viewfinder
  • artifactId: viewfinder-view
  • version: 1.4.0-alpha08

Artifact androidx.camera.viewfinder:viewfinder-view:1.4.0-alpha08 it located at Google repository (https://maven.google.com/)

Overview

Handles logging requests inside CameraX. Log messages are output only if: - The minimum logging level allows for it. The minimum logging level is set via Logger.setMinLogLevel(int), which should typically be called during the process of configuring CameraX. - The log tag is . This can be configured by setting the system property `setprop log.tag.TAG LEVEL`, where TAG is the log tag, and LEVEL is , , or .

A typical usage of the Logger looks as follows:

     try {
         int quotient = dividend / divisor;
     } catch (ArithmeticException exception) {
         Logger.e(TAG, "Divide operation error", exception);
     }
 

If an action has to be performed alongside logging, or if building the log message is costly, perform a log level check before attempting to log.

     try {
         int quotient = dividend / divisor;
     } catch (ArithmeticException exception) {
         if (Logger.isErrorEnabled(TAG)) {
             Logger.e(TAG, "Divide operation error", exception);
             doSomething();
         }
     }
 

Summary

Methods
public static voidd(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static voidd(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

public static voide(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static voide(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

public static voidi(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static voidi(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

public static booleanisDebugEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level.

public static booleanisErrorEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level.

public static booleanisInfoEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level.

public static booleanisWarnEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level.

public static voidw(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static voidw(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

from java.lang.Objectclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods

public static boolean isDebugEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level. This is true when the minimum logging level is less than or equal to , or if the log level of tag was explicitly set to at least.

public static boolean isInfoEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level. This is true when the minimum logging level is less than or equal to , or if the log level of tag was explicitly set to at least.

public static boolean isWarnEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level. This is true when the minimum logging level is less than or equal to , or if the log level of tag was explicitly set to at least.

public static boolean isErrorEnabled(java.lang.String tag)

Returns true if logging with the tag tag is enabled at the level. This is true when the minimum logging level is less than or equal to , or if the log level of tag was explicitly set to at least.

public static void d(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static void d(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

public static void i(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static void i(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

public static void w(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static void w(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

public static void e(java.lang.String tag, java.lang.String message)

Logs the given message if the tag is loggable.

public static void e(java.lang.String tag, java.lang.String message, java.lang.Throwable throwable)

Logs the given message and the exception's stacktrace if the tag is loggable.

Source

/*
 * Copyright 2022 The Android Open Source Project
 *
 * 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 androidx.camera.viewfinder.internal.utils;

import android.os.Build;
import android.util.Log;

import androidx.annotation.IntRange;
import androidx.annotation.NonNull;

/**
 * Handles logging requests inside CameraX. Log messages are output only if:
 * - The minimum logging level allows for it. The minimum logging level is set via
 * {@link #setMinLogLevel(int)}, which should typically be called during the process of configuring
 * CameraX.
 * - The log tag is {@linkplain Log#isLoggable(String, int) loggable}. This can be configured
 * by setting the system property `setprop log.tag.TAG LEVEL`, where TAG is the log tag, and
 * LEVEL is {@link Log#DEBUG}, {@link Log#INFO}, {@link Log#WARN} or {@link Log#ERROR}.
 * <p> A typical usage of the Logger looks as follows:
 * <pre>
 *     try {
 *         int quotient = dividend / divisor;
 *     } catch (ArithmeticException exception) {
 *         Logger.e(TAG, "Divide operation error", exception);
 *     }
 * </pre>
 * <p> If an action has to be performed alongside logging, or if building the log message is costly,
 * perform a log level check before attempting to log.
 * <pre>
 *     try {
 *         int quotient = dividend / divisor;
 *     } catch (ArithmeticException exception) {
 *         if (Logger.isErrorEnabled(TAG)) {
 *             Logger.e(TAG, "Divide operation error", exception);
 *             doSomething();
 *         }
 *     }
 * </pre>
 */
public final class Logger {

    /** On API levels strictly below 24, the log tag's length must not exceed 23 characters. */
    private static final int MAX_TAG_LENGTH = 23;

    static final int DEFAULT_MIN_LOG_LEVEL = Log.DEBUG;
    private static int sMinLogLevel = DEFAULT_MIN_LOG_LEVEL;

    private Logger() {
    }

    /**
     * Returns {@code true} if logging with the truncated tag {@code truncatedTag} is
     * enabled at the {@code logLevel} level.
     */
    private static boolean isLogLevelEnabled(@NonNull String truncatedTag, int logLevel) {
        return sMinLogLevel <= logLevel || Log.isLoggable(truncatedTag, logLevel);
    }

    /**
     * Sets the minimum logging level to use in {@link Logger}. After calling this method, only logs
     * at the level {@code logLevel} and above are output.
     */
    static void setMinLogLevel(@IntRange(from = Log.DEBUG, to = Log.ERROR) int logLevel) {
        sMinLogLevel = logLevel;
    }

    /**
     * Returns current minimum logging level.
     */
    static int getMinLogLevel() {
        return sMinLogLevel;
    }

    /**
     * Resets the minimum logging level to use in {@link Logger} to the default minimum logging
     * level. After calling this method, only logs at the default level and above are output.
     */
    static void resetMinLogLevel() {
        sMinLogLevel = DEFAULT_MIN_LOG_LEVEL;
    }

    /**
     * Returns {@code true} if logging with the tag {@code tag} is enabled at the {@link Log#DEBUG}
     * level. This is true when the minimum logging level is less than or equal to
     * {@link Log#DEBUG}, or if the log level of {@code tag} was explicitly set to
     * {@link Log#DEBUG} at least.
     */
    public static boolean isDebugEnabled(@NonNull String tag) {
        return isLogLevelEnabled(truncateTag(tag), Log.DEBUG);
    }

    /**
     * Returns {@code true} if logging with the tag {@code tag} is enabled at the {@link Log#INFO}
     * level. This is true when the minimum logging level is less than or equal to
     * {@link Log#INFO}, or if the log level of {@code tag} was explicitly set to
     * {@link Log#INFO} at least.
     */
    public static boolean isInfoEnabled(@NonNull String tag) {
        return isLogLevelEnabled(truncateTag(tag), Log.INFO);
    }

    /**
     * Returns {@code true} if logging with the tag {@code tag} is enabled at the {@link Log#WARN}
     * level. This is true when the minimum logging level is less than or equal to
     * {@link Log#WARN}, or if the log level of {@code tag} was explicitly set to
     * {@link Log#WARN} at least.
     */
    public static boolean isWarnEnabled(@NonNull String tag) {
        return isLogLevelEnabled(truncateTag(tag), Log.WARN);
    }

    /**
     * Returns {@code true} if logging with the tag {@code tag} is enabled at the {@link Log#ERROR}
     * level. This is true when the minimum logging level is less than or equal to
     * {@link Log#ERROR}, or if the log level of {@code tag} was explicitly set to
     * {@link Log#ERROR} at least.
     */
    public static boolean isErrorEnabled(@NonNull String tag) {
        return isLogLevelEnabled(truncateTag(tag), Log.ERROR);
    }

    /**
     * Logs the given {@link Log#DEBUG} message if the tag is
     * {@linkplain #isDebugEnabled(String) loggable}.
     */
    public static void d(@NonNull String tag, @NonNull String message) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.DEBUG)) {
            Log.d(truncatedTag, message);
        }
    }

    /**
     * Logs the given {@link Log#DEBUG} message and the exception's stacktrace if the tag is
     * {@linkplain #isDebugEnabled(String) loggable}.
     */
    public static void d(@NonNull String tag, @NonNull String message,
            @NonNull final Throwable throwable) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.DEBUG)) {
            Log.d(truncatedTag, message, throwable);
        }
    }

    /**
     * Logs the given {@link Log#INFO} message if the tag is
     * {@linkplain #isInfoEnabled(String) loggable}.
     */
    public static void i(@NonNull String tag, @NonNull String message) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.INFO)) {
            Log.i(truncatedTag, message);
        }
    }

    /**
     * Logs the given {@link Log#INFO} message and the exception's stacktrace if the tag is
     * {@linkplain #isInfoEnabled(String) loggable}.
     */
    public static void i(@NonNull String tag, @NonNull String message,
            @NonNull final Throwable throwable) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.INFO)) {
            Log.i(truncatedTag, message, throwable);
        }
    }

    /**
     * Logs the given {@link Log#WARN} message if the tag is
     * {@linkplain #isWarnEnabled(String) loggable}.
     */
    public static void w(@NonNull String tag, @NonNull String message) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.WARN)) {
            Log.w(truncatedTag, message);
        }
    }

    /**
     * Logs the given {@link Log#WARN} message and the exception's stacktrace if the tag is
     * {@linkplain #isWarnEnabled(String) loggable}.
     */
    public static void w(@NonNull String tag, @NonNull String message,
            @NonNull final Throwable throwable) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.WARN)) {
            Log.w(truncatedTag, message, throwable);
        }
    }

    /**
     * Logs the given {@link Log#ERROR} message if the tag is
     * {@linkplain #isErrorEnabled(String) loggable}.
     */
    public static void e(@NonNull String tag, @NonNull String message) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.ERROR)) {
            Log.e(truncatedTag, message);
        }
    }

    /**
     * Logs the given {@link Log#ERROR} message and the exception's stacktrace if the tag is
     * {@linkplain #isErrorEnabled(String) loggable}.
     */
    public static void e(@NonNull String tag, @NonNull String message,
            @NonNull final Throwable throwable) {
        final String truncatedTag = truncateTag(tag);
        if (isLogLevelEnabled(truncatedTag, Log.ERROR)) {
            Log.e(truncatedTag, message, throwable);
        }
    }

    /**
     * Truncates the tag so it can be used to log.
     * <p>
     * On API 24, the tag length limit of 23 characters was removed.
     */
    @NonNull
    private static String truncateTag(@NonNull String tag) {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.N && MAX_TAG_LENGTH < tag.length()) {
            return tag.substring(0, MAX_TAG_LENGTH);
        }
        return tag;
    }
}