From scratch

It is possible to create a CompilationUnit from scratch using the factory methods on AST. These method names start with new.... The following is an example that creates a HelloWorld class.

The first snippet is the generated output:

package example; 
import java.util.*; 
public class HelloWorld {  
public static void main(String[] args) {   
System.out.println("Hello" + " world");  
} 
} 

The following snippet is the corresponding code that generates the output.

AST ast = new AST();  
CompilationUnit unit = ast.newCompilationUnit();  
PackageDeclaration packageDeclaration = ast.newPackageDeclaration(); 
packageDeclaration.setName(ast.newSimpleName("example"));  
unit.setPackage(packageDeclaration);  
ImportDeclaration importDeclaration = ast.newImportDeclaration();
QualifiedName name =   
ast.newQualifiedName(    
 ast.newSimpleName("java"),   
 ast.newSimpleName("util"));  
importDeclaration.setName(name); 
importDeclaration.setOnDemand(true); 
unit.imports().add(importDeclaration);  
TypeDeclaration type = ast.newTypeDeclaration();  
type.setInterface(false);  
type.setModifiers(Modifier.PUBLIC);  
type.setName(ast.newSimpleName("HelloWorld"));  
MethodDeclaration methodDeclaration = ast.newMethodDeclaration();  
methodDeclaration.setConstructor(false);  
methodDeclaration.setModifiers(Modifier.PUBLIC | Modifier.STATIC);  
methodDeclaration.setName(ast.newSimpleName("main")); 
methodDeclaration.setReturnType(ast.newPrimitiveType(PrimitiveType.VOID));  
SingleVariableDeclaration variableDeclaration = ast.newSingleVariableDeclaration();
variableDeclaration.setModifiers(Modifier.NONE);  
variableDeclaration.setType(
ast.newArrayType(
      ast.newSimpleType(ast.newSimpleName("String"))));  
variableDeclaration.setName(ast.newSimpleName("args"));  
methodDeclaration.parameters().add(variableDeclaration);  
org.eclipse.jdt.core.dom.Block block = ast.newBlock();  
MethodInvocation methodInvocation = ast.newMethodInvocation();  
name =    
  ast.newQualifiedName(    
      ast.newSimpleName("System"),    
      ast.newSimpleName("out"));  
methodInvocation.setExpression(name);  
methodInvocation.setName(ast.newSimpleName("println"));   
InfixExpression infixExpression = ast.newInfixExpression();  
infixExpression.setOperator(InfixExpression.Operator.PLUS);  
StringLiteral literal = ast.newStringLiteral();  
literal.setLiteralValue("Hello");  
infixExpression.setLeftOperand(literal);  
literal = ast.newStringLiteral();  
literal.setLiteralValue(" world");  
infixExpression.setRightOperand(literal);  
methodInvocation.arguments().add(infixExpression);  
ExpressionStatement expressionStatement =
  ast.newExpressionStatement(methodInvocation);  
block.statements().add(expressionStatement);  
methodDeclaration.setBody(block);  
type.bodyDeclarations().add(methodDeclaration);  
unit.types().add(type);

- posted by Pop @ 5:08 PM