Android 引入AspectJ

 AspectJ 编译  

      AspectJ 编译是通过AJC （AspectJ Complier） 编译工具编译Aspect代码，Android 项目中引入AspectJ 需要设置AJC 相关编译参数才能编译。

        

• l AspectJ比较强大，除了支持对source文件（即aj文件、或@AspectJ注解的Java文件，或普通java文件）直接进行编译外，
• l 还能对Java字节码（即对class文件）进行处理。有感兴趣的同学可以对aspectj-test小例子的class文件进行反编译，你会发现AspectJ无非是在被选中的JPoint的地方加一些hook函数。当然Before就是在调用JPoint之前加，After就是在JPoint返回之前加。
• l 更高级的做法是当class文件被加载到虚拟机后，由虚拟机根据AOP的规则进行hook。

       以下对第二种使用方式进行说明

    一、在需要添加的Module 中的build.gradle中添加gradle脚本

        1、新建aopconfig.gradle 文件

            

import org.aspectj.bridge.IMessage
import org.aspectj.bridge.MessageHandler
import org.aspectj.tools.ajc.Main

buildscript {
    repositories {
        jcenter()
        google()
    }
    dependencies {
        classpath 'org.aspectj:aspectjtools:1.8.9'
    }
}

final def log = project.logger
final def variants = project.android.applicationVariants

variants.all { variant ->
    if (!variant.buildType.isDebuggable()) {
        log.debug("Skipping non-debuggable build type '${variant.buildType.name}'.")
        return
    }

    JavaCompile javaCompile = variant.javaCompile
    javaCompile.doLast {
        String[] args = ["-showWeaveInfo",
                         "-1.5",
                         "-inpath", javaCompile.destinationDir.toString(),
                         "-aspectpath", javaCompile.classpath.asPath,
                         "-d", javaCompile.destinationDir.toString(),
                         "-classpath", javaCompile.classpath.asPath,
                         "-bootclasspath", project.android.bootClasspath.join(File.pathSeparator)]
        log.debug "ajc args: " + Arrays.toString(args)

        MessageHandler handler = new MessageHandler(true)
        new Main().run(args, handler)
        for (IMessage message : handler.getMessages(null, true)) {
            switch (message.getKind()) {
                case IMessage.ABORT:
                case IMessage.ERROR:
                case IMessage.FAIL:
                    log.error message.message, message.thrown
                    break
                case IMessage.WARNING:
                    log.warn message.message, message.thrown
                    break
                case IMessage.INFO:
                    log.info message.message, message.thrown
                    break
                case IMessage.DEBUG:
                    log.debug message.message, message.thrown
                    break
            }
        }
    }
}

dependencies {
    implementation 'org.aspectj:aspectjrt:1.8.9'
}

        2、在app 中的build.gradle 中引入aopconfig.gradle，整个配置完成

            

apply from : "aopconfig.gradle"

   二、使用Gradle Plugin设置编译参数

•                 自定义Gradle Plugin
  
•                 在apply 方法中实现参数设置
  

                

import com.android.build.gradle.LibraryPlugin
import org.aspectj.bridge.IMessage
import org.aspectj.bridge.MessageHandler
import org.aspectj.tools.ajc.Main
import org.gradle.api.Plugin
import org.gradle.api.Project
import org.gradle.api.tasks.compile.JavaCompile

public class AopPlugin implements Plugin {

    @Override
    void apply(Project project) {
        //判断应用此Module的Target类型是AppPlugin还是LibraryPlugin
        def hasApp = project.plugins.withType(AppPlugin)
        def hasLibrary = project.plugins.withType(LibraryPlugin)
        if (!hasApp && !hasLibrary) {
            throw new IllegalStateException("'android' or 'android-library' plugin required.")
        }

        final def log = project.logger
        final def variants
        if (hasApp) {
            variants = project.android.applicationVariants
        } else {
            variants = project.android.libraryVariants
        }

        //添加依赖
        project.dependencies {
            compile 'org.aspectj:aspectjrt:1.8.9'
        }

        variants.all { variant ->
            JavaCompile javaCompile = variant.javaCompile
            javaCompile.doLast {
                String[] args = [
                    "-showWeaveInfo",
                    "-1.5",
                    "-inpath", javaCompile.destinationDir.toString(),
                    "-aspectpath", javaCompile.classpath.asPath,
                    "-d", javaCompile.destinationDir.toString(),
                    "-classpath", javaCompile.classpath.asPath,
                    "-bootclasspath", project.android.bootClasspath.join(File.pathSeparator)
                ]

                log.debug "ajc args:" + Arrays.toString(args)
                printf("Aspectj compiler args :" + Arrays.toString(args))
                MessageHandler handler = new MessageHandler(true);
                new Main().run(args, handler);
                for (IMessage message : handler.getMessages(null, true)) {
                    switch (message.getKind()) {
                        case IMessage.ABORT:
                        case IMessage.ERROR:
                        case IMessage.FAIL:
                            log.error message.message, message.thrown
                            break;

                        case IMessage.WARNING:
                            log.warn message.message, message.thrown
                            break;

                        case IMessage.INFO:
                            log.info message.message, message.thrown
                            break;

                        case IMessage.DEBUG:
                            log.info message.message, message.thrown
                            break;
                    }
                }
            }
        }
    }
}

       参数说明：

        

参数	说明
-showWeaveInfo	输入AJC 编译信息
-1.5	声明AJC 支持AspectJ 1.5 版本
-inpath	需要编译的.class 文件目录(包含Jar文件)
-classpath	指定哪里可以找到用户的class 文件
-aspectpath	aspect 编译的Jar文件或者目录路径
-d	编译后输出的目录
-bootclasspath	编译时修改本地的bootcloasspath

         其它参考：
https://eclipse.org/aspectj/doc/released/devguide/ajc-ref.html

AspectJ-specific options:

    -inpath       use classes in dirs and jars/zips in as source

                        ( uses platform-specific path delimiter)

    -injars   use classes in zip files as source

                        ( uses classpath delimiter)

                        deprecated - use inpath instead.

    -aspectpath   weave aspects in .class files from dirs and jars/zip into sources

                        ( uses classpath delimiter)

    -outjar       put output classes in zip file

    -outxml            generate META-INF/aop.xml

    -outxmlfile   specify alternate destination output of -outxml

    -argfile     specify line-delimited list of source files

    -showWeaveInfo      display information about weaving

    -incremental        continuously-running compiler, needs -sourceroots

                        (reads stdin: enter to recompile and 'q' to quit)

    -sourceroots compile all .aj and .java files in

                        ( uses classpath delimiter)

    -crossrefs          generate .ajsym file into the output directory

    -emacssym          generate .ajesym symbol files for emacs support

    -Xlint              same as '-Xlint:warning'

    -Xlint:      set default level for crosscutting messages

                        ( may be ignore, warning, or error)

    -Xlintfile   specify properties file to set per-message levels

                        (cf org/aspectj/weaver/XlintDefault.properties)

    -X                  print help on non-standard options

Standard Eclipse compiler options:

Options enabled by default are prefixed with '+'

Classpath options:

    -cp -classpath

                      specify location for application classes and sources

    -bootclasspath

                      specify location for system classes

    -d           destination directory (if omitted, no directory is created)

    -d none            generate no .class files

    -encoding     specify custom encoding for all sources. Each file/directory can override it

                      when suffixed with '['']' (e.g. X.java[utf8])

Compliance options:

    -1.3              use 1.3 compliance level (implicit -source 1.3 -target 1.1)

    -1.4            + use 1.4 compliance level

    -1.5 -5 -5.0      use 1.5 compliance (-source 1.5 -target 1.5)

    -1.6 -6 -6.0      use 1.6 compliance (-source 1.6 -target 1.6)

    -1.7 -7 -7.0      use 1.7 compliance (-source 1.7 -target 1.7)

    -1.8 -8 -8.0      use 1.8 compliance (-source 1.8 -target 1.8)

    -source   set source level: 1.3 to 1.8 (or 5, 5.0, etc)

    -target   set classfile target: 1.1 to 1.8 (or 5, 5.0, etc)

Warning options:

    -deprecation        + deprecation outside deprecated code

    -nowarn -warn:none disable all warnings

    -warn:    enable exactly the listed warnings

    -warn:+  enable additional warnings

    -warn:-  disable specific warnings

      allDeadCode          dead code including trivial if(DEBUG) check

      allDeprecation      deprecation including inside deprecated code

      allJavadoc          invalid or missing javadoc

      allOver-ann          all missing @Override annotations

      all-static-method    all method can be declared as static warnings

      assertIdentifier  + 'assert' used as identifier

      boxing              autoboxing conversion

      charConcat        + char[] in String concat

      compareIdentical  + comparing identical expressions

      conditionAssign      possible accidental boolean assignment

      constructorName    + method with constructor name

      deadCode          + dead code excluding trivial if (DEBUG) check

      dep-ann              missing @Deprecated annotation

      deprecation        + deprecation outside deprecated code

      discouraged        + use of types matching a discouraged access rule

      emptyBlock          undocumented empty block

      enumIdentifier      'enum' used as identifier

      enumSwitch          incomplete enum switch

      fallthrough          possible fall-through case

      fieldHiding          field hiding another variable

      finalBound          type parameter with final bound

      finally            + finally block not completing normally

      forbidden          + use of types matching a forbidden access rule

      hashCode              missing hashCode() method when overriding equals()

      hiding              macro for fieldHiding, localHiding, typeHiding and

                          maskedCatchBlock

      includeAssertNull    raise null warnings for variables

                          that got tainted in an assert expression

      indirectStatic      indirect reference to static member

      intfAnnotation    + annotation type used as super interface

      intfNonInherited  + interface non-inherited method compatibility

      intfRedundant        find redundant superinterfaces

      javadoc              invalid javadoc

      localHiding          local variable hiding another variable

      maskedCatchBlock  + hidden catch block

      nls                  string literal lacking non-nls tag //$NON-NLS-$

      noEffectAssign    + assignment without effect

      null                potential missing or redundant null check

      nullDereference    + missing null check

      over-ann            missing @Override annotation (superclass)

      paramAssign          assignment to a parameter

      pkgDefaultMethod  + attempt to override package-default method

      raw                + usage of raw type

      semicolon            unnecessary semicolon, empty statement

      serial            + missing serialVersionUID

      specialParamHiding  constructor or setter parameter hiding a field

      static-method        method can be declared as static

      static-access        macro for indirectStatic and staticReceiver

      staticReceiver    + non-static reference to static member

      super                overriding a method without making a super invocation

      suppress          + enable @SuppressWarnings

                          When used with -err:, it can also silent optional

                          errors and warnings

      syncOverride        missing synchronized in synchr. method override

      syntheticAccess      synthetic access for innerclass

      tasks() tasks identified by tags inside comments

      typeHiding        + type parameter hiding another type

      unavoidableGenericProblems + ignore unavoidable type safety problems

                                  due to raw APIs

      unchecked          + unchecked type operation

      unnecessaryElse      unnecessary else clause

      unqualifiedField    unqualified reference to field

      unused              macro for unusedAllocation, unusedArgument,

                              unusedImport, unusedLabel, unusedLocal,

                              unusedPrivate, unusedThrown, and unusedTypeArgs

      unusedAllocation    allocating an object that is not used

      unusedArgument      unread method parameter

      unusedImport      + unused import declaration

      unusedLabel        + unused label

      unusedLocal        + unread local variable

      unusedPrivate      + unused private member declaration

      unusedThrown        unused declared thrown exception

      unusedTypeArgs    + unused type arguments for method and constructor

      uselessTypeCheck    unnecessary cast/instanceof operation

      varargsCast        + varargs argument need explicit cast

      warningToken      + unsupported or unnecessary @SuppressWarnings

AspectJ Api 相关核心类

    org.aspectj.lang.annotation

        包含了AspectJ 使用的注解

     org.aspectj.lang

        JoinPoint：表示切入点，带有切入点的相关信息

        ProceedingJoinPoint: JoinPoint 子类，提供执行切入点源代码的能力，只能与Advice 的Around 配合使用。

        Signature: PointCut 签名信息。

        org.aspectj.lang.reflect

            包含JoinPoint 具体的Signature接口类 

        org.aspectj.runtime.reflect

        包含JoinPoint 具体的Signature接口类的实现类

            

        org.aspectj.tools.ajbrowser

                AspectJ 搜索核心了

        org.aspectj.tools.ajc

                Main: AspectJ AJC 入口