WMS类图结构分析-android12

为什么要分析类图？

WMS是一个复杂的模块，就像一个很大的家族，里面有各种角色，认识类图就像是认识WMS模块中的各个角色，不先把人认清楚了，怎么更好的理解他们之间的交互？

我觉得，这也是面向对象的语言魅力，面向对象的语言构建了一个小小的世界，每一个类都是其中的一个角色。

首先插一张类图，方便后面的分析

具体类图小析

ConfigurationContainer

类属性分析

这是WMS模块中的始祖级别的类，WMS中所有的类都继承于它。

ConfigurationContainer类中主要有三个Configuration对象,Configuration 本事就是各种基础参数 mode的记录

mRequestedOverrideConfiguration：当前应用主动请求的Configuration

mResolvedOverrideConfiguration：mRequestedOverrideConfiguration 经过子类的的调整后的对应容器请求的config，子类会重现相关的方法。

mFullConfiguration：当前使用的Configuration。

类方法分析：

onConfigurationChanged（）

从方法的注释中可以看到，这个方法的作用是当父节点更新后，需要更新自己的全部configuration.

public abstract class ConfigurationContainer<E extends ConfigurationContainer> {
    
    //下面三个Configuration对象是配置相关的基础对象，onfiguration对象本身主要是一些参数的配置。
    /**
     * Contains requested override configuration settings applied to this configuration container. 当前应用主动请求的所有config
     */
    private Configuration mRequestedOverrideConfiguration = new Configuration();
    
     /**
     * Contains the requested override configuration with parent and policy constraints applied.
     * This is the set of overrides that gets applied to the full and merged configurations.为mRequestedOverrideConfiguration 经过子类的的调整后的对应容器请求的config
     */
    private Configuration mResolvedOverrideConfiguration = new Configuration();
    
     /**
     * Contains full configuration applied to this configuration container. Corresponds to full
     * parent's config with applied {@link #mResolvedOverrideConfiguration}.为父亲的config（mFullConfiguration） 加上自己的mResolvedOverrideConfiguration 组合成自身的mResolvedOverrideConfiguration
     */
    private Configuration mFullConfiguration = new Configuration();//这个是返回的configuration
    
     /**
     * Returns full configuration applied to this configuration container.
     * This method should be used for getting settings applied in each particular level of the
     * hierarchy.从getConfiguration函数中可以看出，mFullConfiguration是在使用的congfiguration
     */
    public Configuration getConfiguration() {
        return mFullConfiguration;
    }
    
    //onConfigurationChanged 当配置发生改变时调用，会在onParentChanged中调用
    public void onConfigurationChanged(Configuration newParentConfig) {
        mResolvedTmpConfig.setTo(mResolvedOverrideConfiguration); //先保存mResolvedOverrideConfiguration
        resolveOverrideConfiguration(newParentConfig);//mResolvedOverrideConfiguration从newParentConfig中算出来
        mFullConfiguration.setTo(newParentConfig);//mFullConfiguration 设为 newParentConfig
        mFullConfiguration.updateFrom(mResolvedOverrideConfiguration);//重新计算mFullConfiguration
        onMergedOverrideConfigurationChanged();
        if (!mResolvedTmpConfig.equals(mResolvedOverrideConfiguration)) {
            // This depends on the assumption that change-listeners don't do
            // their own override resolution. This way, dependent hierarchies
            // can stay properly synced-up with a primary hierarchy's constraints.
            // Since the hierarchies will be merged, this whole thing will go away
            // before the assumption will be broken.
            // Inform listeners of the change.
            for (int i = mChangeListeners.size() - 1; i >= 0; --i) {
                mChangeListeners.get(i).onRequestedOverrideConfigurationChanged(
                        mResolvedOverrideConfiguration);//通知子节点更新
            }
        }
        for (int i = mChangeListeners.size() - 1; i >= 0; --i) {
            mChangeListeners.get(i).onMergedOverrideConfigurationChanged(
                    mMergedOverrideConfiguration);
        }
        for (int i = getChildCount() - 1; i >= 0; --i) {
            dispatchConfigurationToChild(getChildAt(i), mFullConfiguration);
        }
    }
    
    //应该是parent发生变化是被调用
    void onParentChanged(ConfigurationContainer newParent, ConfigurationContainer oldParent) {
        // Removing parent usually means that we've detached this entity to destroy it or to attach
        // to another parent. In both cases we don't need to update the configuration now.
        if (newParent != null) {
            // Update full configuration of this container and all its children.
            onConfigurationChanged(newParent.mFullConfiguration);
            // Update merged override configuration of this container and all its children.
            onMergedOverrideConfigurationChanged();
        }
    }
}
 and all its children.
            onMergedOverrideConfigurationChanged();
        }
    }
}
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