19 Glide 可复用的源码

项目地址：https://github.com/bumptech/glide
官方文档：http://bumptech.github.io/glide/
中文文档：https://muyangmin.github.io/glide-docs-cn/
参考链接：https://blog.csdn.net/guolin_blog/article/details/53939176
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文章目录：
Glide 详解
Glide 源码分析执行流程

参数检查

源码：

package xian.xiao.tao.util;

import android.text.TextUtils;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;

import java.util.Collection;

/**
 * Contains common assertions.
 */
public final class Preconditions {

    private Preconditions() {
        // Utility class.
    }

    public static void checkArgument(boolean expression, @NonNull String message) {
        if (!expression) {
            throw new IllegalArgumentException(message);
        }
    }

    @NonNull
    public static <T> T checkNotNull(@Nullable T arg) {
        return checkNotNull(arg, "Argument must not be null");
    }

    @NonNull
    public static <T> T checkNotNull(@Nullable T arg, @NonNull String message) {
        if (arg == null) {
            throw new NullPointerException(message);
        }
        return arg;
    }

    @NonNull
    public static String checkNotEmpty(@Nullable String string) {
        if (TextUtils.isEmpty(string)) {
            throw new IllegalArgumentException("Must not be null or empty");
        }
        return string;
    }

    @NonNull
    public static <T extends Collection<Y>, Y> T checkNotEmpty(@NonNull T collection) {
        if (collection.isEmpty()) {
            throw new IllegalArgumentException("Must not be empty.");
        }
        return collection;
    }
}

使用：

Preconditions.checkNotNull(
    context,
    "You cannot start a load on a not yet attached View or a Fragment where getActivity() "
        + "returns null (which usually occurs when getActivity() is called before the Fragment "
        + "is attached or after the Fragment is destroyed).");