Detector.UastScanner源码与JavaPsiScanner源码（Lint）

Detector.UastScanner源码：javadoc网址

javadoc只提供到了25.5.0这个版本，更新的版本比如26.2.0需要在代码仓库中引入才能看到SourceCodeScanner。

由于API转变是从JavaScanner转换到JavaPsiScanner再到SourceCodeScanner，想看一下JavaPsiScanner的源码解释，可以回退版本25.3.0。

将lint版本在代码仓库中回退到25.3.0，可以看到JavaPsiScanner源码，然后发现它没有单独的类，它是一个接口类，是和JavaScanner一起在Detector类中。如下：

package com.android.tools.lint.detector.api;

import com.android.annotations.NonNull;
import com.android.annotations.Nullable;
import com.android.resources.ResourceFolderType;
import com.android.resources.ResourceType;
import com.android.tools.lint.client.api.JavaParser.ResolvedClass;
import com.android.tools.lint.client.api.JavaParser.ResolvedMethod;
import com.android.tools.lint.client.api.LintDriver;
import com.google.common.annotations.Beta;
import com.intellij.psi.JavaElementVisitor;
import com.intellij.psi.PsiClass;
import com.intellij.psi.PsiElement;
import com.intellij.psi.PsiJavaCodeReferenceElement;
import com.intellij.psi.PsiMethod;
import com.intellij.psi.PsiMethodCallexpression;
import com.intellij.psi.PsiNewexpression;
import com.intellij.psi.PsiTypeParameter;
import java.io.File;
import java.util.ArrayList;
import java.util.Collection;
import java.util.EnumSet;
import java.util.List;
import java.util.Map;
import lombok.ast.AstVisitor;
import lombok.ast.ClassDeclaration;
import lombok.ast.ConstructorInvocation;
import lombok.ast.MethodInvocation;
import lombok.ast.Node;
import org.objectweb.asm.tree.AbstractInsnNode;
import org.objectweb.asm.tree.ClassNode;
import org.objectweb.asm.tree.MethodInsnNode;
import org.objectweb.asm.tree.MethodNode;
import org.w3c.dom.Attr;
import org.w3c.dom.document;
import org.w3c.dom.Element;


@Beta
public abstract class Detector {
    
    @Deprecated @SuppressWarnings("unused") // Still here for third-party rules
    public interface JavaScanner  {
        
        @Nullable
        AstVisitor createJavaVisitor(@NonNull JavaContext context);

        
        @Nullable
        List> getApplicableNodeTypes();

        
        @Nullable
        List getApplicableMethodNames();

        
        void visitMethod(
                @NonNull JavaContext context,
                @Nullable AstVisitor visitor,
                @NonNull MethodInvocation node);

        
        @Nullable
        List getApplicableConstructorTypes();

        
        void visitConstructor(
                @NonNull JavaContext context,
                @Nullable AstVisitor visitor,
                @NonNull ConstructorInvocation node,
                @NonNull ResolvedMethod constructor);

        
        boolean appliesToResourceRefs();

        
        void visitResourceReference(
                @NonNull JavaContext context,
                @Nullable AstVisitor visitor,
                @NonNull Node node,
                @NonNull String type,
                @NonNull String name,
                boolean isframework);

        
        @Nullable
        List applicableSuperClasses();

        
        // TODO: Change signature to pass in the NormalTypeBody instead of the plain Node?
        void checkClass(@NonNull JavaContext context, @Nullable ClassDeclaration declaration,
                @NonNull Node node, @NonNull ResolvedClass resolvedClass);
    }

    
    public interface JavaPsiScanner  {
        
        @Nullable
        JavaElementVisitor createPsiVisitor(@NonNull JavaContext context);

        
        @Nullable
        List> getApplicablePsiTypes();

        
        @Nullable
        List getApplicableMethodNames();

        
        void visitMethod(
                @NonNull JavaContext context,
                @Nullable JavaElementVisitor visitor,
                @NonNull PsiMethodCallexpression call,
                @NonNull PsiMethod method);

        
        @Nullable
        List getApplicableConstructorTypes();

        
        void visitConstructor(
                @NonNull JavaContext context,
                @Nullable JavaElementVisitor visitor,
                @NonNull PsiNewexpression node,
                @NonNull PsiMethod constructor);

        
        @Nullable
        List getApplicableReferenceNames();

        
        void visitReference(
                @NonNull JavaContext context,
                @Nullable JavaElementVisitor visitor,
                @NonNull PsiJavaCodeReferenceElement reference,
                @NonNull PsiElement referenced);

        
        boolean appliesToResourceRefs();

        
        void visitResourceReference(
                @NonNull JavaContext context,
                @Nullable JavaElementVisitor visitor,
                @NonNull PsiElement node,
                @NonNull ResourceType type,
                @NonNull String name,
                boolean isframework);

        
        @Nullable
        List applicableSuperClasses();

        
        void checkClass(@NonNull JavaContext context, @NonNull PsiClass declaration);
    }

    
    public interface ClassScanner  {
        
        void checkClass(@NonNull ClassContext context, @NonNull ClassNode classNode);

        
        @Nullable
        int[] getApplicableAsmNodeTypes();

        
        void checkInstruction(@NonNull ClassContext context, @NonNull ClassNode classNode,
                @NonNull MethodNode method, @NonNull AbstractInsnNode instruction);

        
        @Nullable
        List getApplicableCallNames();

        
        @Nullable
        List getApplicableCallOwners();

        
        void checkCall(@NonNull ClassContext context, @NonNull ClassNode classNode,
                @NonNull MethodNode method, @NonNull MethodInsnNode call);
    }

    
    public interface BinaryResourceScanner {
        
        void checkBinaryResource(@NonNull ResourceContext context);

        
        boolean appliesTo(@NonNull ResourceFolderType folderType);
    }

    
    public interface ResourceFolderScanner {
        
        void checkFolder(@NonNull ResourceContext context, @NonNull String folderName);

        
        boolean appliesTo(@NonNull ResourceFolderType folderType);
    }

    
    public interface XmlScanner {
        
        void visitdocument(@NonNull XmlContext context, @NonNull document document);

        
        void visitElement(@NonNull XmlContext context, @NonNull Element element);

        
        void visitElementAfter(@NonNull XmlContext context, @NonNull Element element);

        
        void visitAttribute(@NonNull XmlContext context, @NonNull Attr attribute);

        
        @Nullable
        Collection getApplicableElements();

        
        @Nullable
        Collection getApplicableAttributes();

        
        @NonNull
        List ALL = new ArrayList<>(0); // NOT Collections.EMPTY!
        // We want to distinguish this from just an *empty* list returned by the caller!
    }

    
    public interface GradleScanner {
        void visitBuildscript(@NonNull Context context, Map sharedData);
    }

    
    public interface OtherFileScanner {
        
        @NonNull
        EnumSet getApplicableFiles();
    }

    
    public void run(@NonNull Context context) {
    }

    
    @Deprecated // Slated for removal in lint 2.0 - this method isn't used
    public boolean appliesTo(@NonNull Context context, @NonNull File file) {
        return false;
    }

    
    public void beforeCheckProject(@NonNull Context context) {
    }

    
    public void afterCheckProject(@NonNull Context context) {
    }

    
    public void beforeCheckLibraryProject(@NonNull Context context) {
    }

    
    public void afterCheckLibraryProject(@NonNull Context context) {
    }

    
    public void beforeCheckFile(@NonNull Context context) {
    }

    
    public void afterCheckFile(@NonNull Context context) {
    }

    
    @NonNull
    @Deprecated // Slated for removal in Lint 2.0
    public Speed getSpeed() {
        return Speed.NORMAL;
    }

    
    @NonNull
    @Deprecated // Slated for removal in Lint 2.0
    public Speed getSpeed(@SuppressWarnings("UnusedParameters") @NonNull Issue issue) {
        // If not overridden, this detector does not distinguish speed by issue type
        return getSpeed();
    }

    // ---- Dummy implementations to make implementing XmlScanner easier: ----

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitdocument(@NonNull XmlContext context, @NonNull document document) {
        // This method must be overridden if your detector does
        // not return something from getApplicableElements or
        // getApplicableAttributes
        assert false;
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitElement(@NonNull XmlContext context, @NonNull Element element) {
        // This method must be overridden if your detector returns
        // tag names from getApplicableElements
        assert false;
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitElementAfter(@NonNull XmlContext context, @NonNull Element element) {
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitAttribute(@NonNull XmlContext context, @NonNull Attr attribute) {
        // This method must be overridden if your detector returns
        // attribute names from getApplicableAttributes
        assert false;
    }

    @SuppressWarnings("javadoc")
    @Nullable
    public Collection getApplicableElements() {
        return null;
    }

    @Nullable
    @SuppressWarnings("javadoc")
    public Collection getApplicableAttributes() {
        return null;
    }

    // ---- Dummy implementations to make implementing JavaScanner easier: ----

    @Deprecated @Nullable @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public AstVisitor createJavaVisitor(@NonNull JavaContext context) {
        return null;
    }

    @Deprecated @Nullable@SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public List> getApplicableNodeTypes() {
        return null;
    }

    @Deprecated @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitMethod(@NonNull JavaContext context, @Nullable AstVisitor visitor,
            @NonNull MethodInvocation node) {
    }

    @Deprecated @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitResourceReference(@NonNull JavaContext context, @Nullable AstVisitor visitor,
            @NonNull Node node, @NonNull String type, @NonNull String name,
            boolean isframework) {
    }

    @Deprecated @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void checkClass(@NonNull JavaContext context, @Nullable ClassDeclaration declaration,
            @NonNull Node node, @NonNull ResolvedClass resolvedClass) {
    }

    @Deprecated @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitConstructor(
            @NonNull JavaContext context,
            @Nullable AstVisitor visitor,
            @NonNull ConstructorInvocation node,
            @NonNull ResolvedMethod constructor) {
    }

    // ---- Dummy implementations to make implementing a ClassScanner easier: ----

    @SuppressWarnings("javadoc")
    public void checkClass(@NonNull ClassContext context, @NonNull ClassNode classNode) {
    }

    @SuppressWarnings("javadoc")
    @Nullable
    public List getApplicableCallNames() {
        return null;
    }

    @SuppressWarnings("javadoc")
    @Nullable
    public List getApplicableCallOwners() {
        return null;
    }

    @SuppressWarnings("javadoc")
    public void checkCall(@NonNull ClassContext context, @NonNull ClassNode classNode,
            @NonNull MethodNode method, @NonNull MethodInsnNode call) {
    }

    @SuppressWarnings("javadoc")
    @Nullable
    public int[] getApplicableAsmNodeTypes() {
        return null;
    }

    @SuppressWarnings("javadoc")
    public void checkInstruction(@NonNull ClassContext context, @NonNull ClassNode classNode,
            @NonNull MethodNode method, @NonNull AbstractInsnNode instruction) {
    }

    // ---- Dummy implementations to make implementing an OtherFileScanner easier: ----

    @NonNull
    public EnumSet getApplicableFiles() {
        return Scope.OTHER_SCOPE;
    }

    // ---- Dummy implementations to make implementing an GradleScanner easier: ----

    public void visitBuildscript(@NonNull Context context, Map sharedData) {
    }

    // ---- Dummy implementations to make implementing a resource folder scanner easier: ----

    public void checkFolder(@NonNull ResourceContext context, @NonNull String folderName) {
    }

    // ---- Dummy implementations to make implementing a binary resource scanner easier: ----

    public void checkBinaryResource(@NonNull ResourceContext context) {
    }

    public boolean appliesTo(@NonNull ResourceFolderType folderType) {
        return true;
    }

    // ---- Dummy implementation to make implementing JavaPsiScanner easier: ----

    @Nullable
    public List getApplicableMethodNames() {
        return null;
    }

    @Nullable @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public List getApplicableConstructorTypes() {
        return null;
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public boolean appliesToResourceRefs() {
        return false;
    }

    @Nullable @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public List applicableSuperClasses() {
        return null;
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitMethod(@NonNull JavaContext context, @Nullable JavaElementVisitor visitor,
            @NonNull PsiMethodCallexpression call, @NonNull PsiMethod method) {
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitConstructor(
            @NonNull JavaContext context,
            @Nullable JavaElementVisitor visitor,
            @NonNull PsiNewexpression node,
            @NonNull PsiMethod constructor) {
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitResourceReference(@NonNull JavaContext context,
            @Nullable JavaElementVisitor visitor, @NonNull PsiElement node,
            @NonNull ResourceType type, @NonNull String name, boolean isframework) {
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void checkClass(@NonNull JavaContext context, @NonNull PsiClass declaration) {
    }

    @Nullable @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public JavaElementVisitor createPsiVisitor(@NonNull JavaContext context) {
        return null;
    }

    @Nullable @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public List> getApplicablePsiTypes() {
        return null;
    }

    @Nullable @SuppressWarnings({"unused", "javadoc"})
    public List getApplicableReferenceNames() {
        return null;
    }

    @SuppressWarnings({"UnusedParameters", "unused", "javadoc"})
    public void visitReference(
            @NonNull JavaContext context,
            @Nullable JavaElementVisitor visitor,
            @NonNull PsiJavaCodeReferenceElement reference,
            @NonNull PsiElement referenced) {
    }
}

lint中解析java代码的第一代分析器JavaScanner在25.2.0版本开始标注废弃，但在代码中仍然存在，在com.android.tools.lint.detector.api.Detector那个类文件中。
现在从第一代开始了解基本方法:
JavaScanner是用于扫描Java源文件解析树的检测器的专用接口，它是一个interface。