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JDT實(shí)際上是將Java代碼構(gòu)建成一個(gè)基于DOM結(jié)構(gòu)的抽象語(yǔ)法樹AST（Abstract Syntax Tree ）。代碼中的每個(gè)部分都對(duì)應(yīng)一個(gè)ASTNode，許多的ASTNode就構(gòu)成了這個(gè)抽象的語(yǔ)法樹。Java Class一般對(duì)應(yīng)Compilation Unit node，該節(jié)點(diǎn)也是AST樹上的頂點(diǎn)。創(chuàng)建一個(gè)AST如下：

java 代碼

ASTParser parser = ASTParser.newParser(AST.JLS3);
parser.setSource("".toCharArray());
CompilationUnit unit = (CompilationUnit) parser.createAST(null);
unit.recordModifications();
AST ast = unit.getAST();

其中createAST，當(dāng)parse需要較長(zhǎng)時(shí)間時(shí)，可以采用createAST(new NullProgressMonitor())，否則直接傳null即可。

recordModifications()用于記錄節(jié)點(diǎn)的變動(dòng)，比如修改、刪除等，當(dāng)需要對(duì)AST樹進(jìn)行變動(dòng)操作時(shí)，必須要預(yù)先調(diào)用這個(gè)方法。

比較重要的是：一個(gè)AST樹上的所有節(jié)點(diǎn)必須都屬于該AST。不允許直接將其他AST樹上的節(jié)點(diǎn)添加該AST樹上。否則會(huì)拋出java.lang.IllegalArgumentException異常。須使用ASTNode.copySubtree(AST target, ASTNode node)返回一個(gè)目標(biāo)樹的深度拷貝，才能進(jìn)行添加操作。例如:

java 代碼

ASTParser parser = ASTParser.newParser(AST.JLS3);
parser.setSource("".toCharArray());
CompilationUnit targetRoot= (CompilationUnit) parser.createAST(null);
targetRoot.recordModifications();
parser.setSource("class T{}”".toCharArray());
CompilationUnit srcRoot= (CompilationUnit) parser.createAST(null);
//這是非法操作，兩者的AST源不一樣
targetRoot.types().add(srcRoot.types().get(0));
//這是合法操作
targetRoot.types().add(ASTNode.copySubtree(
targetRoot.getAST(), (ASTNode) srcRoot.types().get(0)));
//這是合法操作
targetRoot.types().add(targetRoot.getAST().newTypeDeclaration());

現(xiàn)把一些 Java代碼生成對(duì)應(yīng)的ASTNode方式列出來(lái)，供參考：

List 1 生成Package

// package astexplorer;
java 代碼

 

    PackageDeclaration packageDeclaration = ast.newPackageDeclaration();  
    
unit.setPackage(packageDeclaration);  
    
packageDeclaration.setName(ast.newSimpleName("astexplorer"));

List 2 生成Import

// import org.eclipse.swt.SWT;

// import org.eclipse.swt.events.*;

// import org.eclipse.swt.graphics.*;

// import org.eclipse.swt.layout.*;

// import org.eclipse.swt.widgets.*;
java 代碼

 

    for (int i = 0; i < IMPORTS.length; ++i) {  
    
ImportDeclaration importDeclaration = ast.newImportDeclaration();  
    
importDeclaration.setName(ast.newName(getSimpleNames(IMPORTS[i])));  
    
if (IMPORTS[i].indexOf("*") > 0)  
    
importDeclaration.setOnDemand(true);  
    
else  
    
importDeclaration.setOnDemand(false);  
    
  
    
unit.imports().add(importDeclaration);  
    
}

List 3 生成Class Declaration

// public class SampleComposite extends Composite

java 代碼


 

    TypeDeclaration classType = ast.newTypeDeclaration();  
    
classType.setInterface(false);  
    
classType.setModifiers(Modifier.PUBLIC);  
    
classType.setName(ast.newSimpleName("SampleComposite"));  
    
classType.setSuperclass(ast.newSimpleName("Composite"));  
    
unit.types().add(classType);





List 4 生成Constructor Declaration



// public SampleComposite(Composite parent,int style){}

java 代碼


 

    MethodDeclaration methodConstructor = ast.newMethodDeclaration();  
    
methodConstructor.setConstructor(true);  
    
methodConstructor.setModifiers(Modifier.PUBLIC);  
    
methodConstructor.setName(ast.newSimpleName("SampleComposite"));  
    
classType.bodyDeclarations().add(methodConstructor);  
    
  
    
// constructor parameters  
    
  
    
SingleVariableDeclaration variableDeclaration = ast.newSingleVariableDeclaration();  
    
variableDeclaration.setModifiers(Modifier.NONE);  
    
variableDeclaration.setType(ast.newSimpleType(ast.newSimpleName("Composite")));  
    
variableDeclaration.setName(ast.newSimpleName("parent"));  
    
methodConstructor.parameters().add(variableDeclaration);  
    
  
    
variableDeclaration = ast.newSingleVariableDeclaration();  
    
variableDeclaration.setModifiers(Modifier.NONE);  
    
variableDeclaration.setType(ast.newPrimitiveType(PrimitiveType.INT));  
    
variableDeclaration.setName(ast.newSimpleName("style"));  
    
methodConstructor.parameters().add(variableDeclaration);  
    

    
Block constructorBlock = ast.newBlock();  
    
methodConstructor.setBody(constructorBlock);

 List 5 生成Spuer Invocation



// super(parent,style)

java 代碼


 

    SuperConstructorInvocation superConstructorInvocation = ast.newSuperConstructorInvocation();  
    
constructorBlock.statements().add(superConstructorInvocation);  
    
Expression exp = ast.newSimpleName("parent");  
    
superConstructorInvocation.arguments().add(exp);  
    
superConstructorInvocation.arguments().add(ast.newSimpleName("style"));



List 6 生成ClassInstanceCreation



// GridLayout gridLayout = new GridLayout();

java 代碼


 

    VariableDeclarationFragment vdf = ast.newVariableDeclarationFragment();  
    
vdf.setName(ast.newSimpleName("gridLayout"));  
    
ClassInstanceCreation cc = ast.newClassInstanceCreation();  
    
cc.setName(ast.newSimpleName("GridLayout"));  
    
vdf.setInitializer(cc);  
    
VariableDeclarationStatement vds = ast.newVariableDeclarationStatement(vdf);  
    
vds.setType(ast.newSimpleType(ast.newSimpleName("GridLayout"))); 
    
constructBlock.statements().add(vds);



// Label label = new Label(this,SWT.NONE);

java 代碼


 

    VariableDeclarationFragment vdf = ast.newVariableDeclarationFragment();  
    
vdf.setName(ast.newSimpleName("label"));  
    
cc = ast.newClassInstanceCreation();  
    
cc.setName(ast.newSimpleName("Label"));  
    
cc.arguments().add(ast.newThisExpression());  
    
cc.arguments().add(ast.newName(getSimpleNames("SWT.NONE")));  
    
vdf.setInitializer(cc);  

    
    
VariableDeclarationStatement vds = ast.newVariableDeclarationStatement(vdf);  
    
vds.setType(ast.newSimpleType(ast.newSimpleName("Label")));  
    
constructBlock.statements().add(vds);



List 7生成MethodInvocation



// setLayout(gridLayout);

java 代碼


 

    MethodInvocation mi = ast.newMethodInvocation();  
    
mi.setName(ast.newSimpleName("setLayout"));  
    
mi.arguments().add(ast.newSimpleName("gridLayout")); 
    
constructorBlock.statements().add(ast.newExpressionStatement(mi));

// label.setText("Press the button to close:");

         java 代碼




    mi = ast.newMethodInvocation();   
    
mi.setExpression(ast.newSimpleName("label"));   
    
mi.setName(ast.newSimpleName("setText"));   
    
StringLiteral sl = ast.newStringLiteral();   
    
sl.setLiteralValue("Press the button to close:");   
    
mi.arguments().add(sl);   
    
constructorBlock.statements().add(ast.newExpressionStatement(mi));

// label.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_CENTER));

           java 代碼



    mi = ast.newMethodInvocation();   
    
mi.setExpression(ast.newSimpleName("label"));   
    
mi.setName(ast.newSimpleName("setLayoutData"));   
    
  
    
cc = ast.newClassInstanceCreation();   
    
cc.setName(ast.newSimpleName("GridData"));   
    
cc.arguments().add(ast.newName(getSimpleNames("GridData.HORIZONTAL_ALIGN_CENTER")));   
    
mi.arguments().add(cc);   
    
constructorBlock.statements().add(ast.newExpressionStatement(mi));  
    




 // Button button = new Button(this,SWT.PUSH);
java 代碼



    vdf = ast.newVariableDeclarationFragment();   
    
vdf.setName(ast.newSimpleName("button"));   
    
vds = ast.newVariableDeclarationStatement(vdf);   
    
vds.setType(ast.newSimpleType(ast.newSimpleName("Button")));   
    
constructorBlock.statements().add(vds);   
    
  
    
cc = ast.newClassInstanceCreation();   
    
cc.setName(ast.newSimpleName("Button"));   
    
vdf.setInitializer(cc);   
    
cc.arguments().add(ast.newThisExpression());   
    
cc.arguments().add(ast.newName(getSimpleNames("SWT.PUSH")));  
    



// button.addSelectionListener(new SelectionAdapter() {}); 
    java 代碼



    mi = ast.newMethodInvocation();   
    
constructorBlock.statements().add(ast.newExpressionStatement(mi));   
    
mi.setExpression(ast.newSimpleName("button"));   
    
mi.setName(ast.newSimpleName("addSelectionListener"));   
    
  
    
ClassInstanceCreation ci = ast.newClassInstanceCreation();   
    
ci.setName(ast.newSimpleName("SelectionAdapter"));   
    
mi.arguments().add(ci);   
    
AnonymousClassDeclaration cd = ast.newAnonymousClassDeclaration();   
    
ci.setAnonymousClassDeclaration(cd); 













































// public void setup(){super.setUp()}


    
        
            MethodDeclaration methodConstructor = ast.newMethodDeclaration();

                    methodConstructor.modifiers().add(

                            ast.newModifier(ModifierKeyword.PUBLIC_KEYWORD));

                    methodConstructor.setName(ast.newSimpleName("setUp"));
        
    
            Block constructorBlock = ast.newBlock();

            methodConstructor.setBody(constructorBlock);
            SuperMethodInvocation smi = ast.newSuperMethodInvocation();

            smi.setName(ast.newSimpleName("setUp"));

            ExpressionStatement es = ast.newExpressionStatement(smi);

            constructorBlock.statements().add(es);
            // set exception

            List targetExNames = methodConstructor.thrownExceptions();

            Name targetExName = ast.newName(Exception.class.getName());

            targetExNames.add(targetExName);
            methodConstructor.setJavadoc(JavaDocHelper.getJavaDoc(ast,

                    JavaDocHelper.setUpDoc, null, null));

            classType.bodyDeclarations().add(methodConstructor);

posted on 2008-07-14 13:21 Daniel 閱讀(327) 評(píng)論(0) 編輯收藏所屬分類: Eclipse的相關(guān)

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