io.ebean.enhance.entity.DefaultConstructor Maven / Gradle / Ivy

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package io.ebean.enhance.entity;

import io.ebean.enhance.asm.ClassVisitor;
import io.ebean.enhance.asm.Label;
import io.ebean.enhance.asm.MethodVisitor;
import io.ebean.enhance.asm.Opcodes;
import io.ebean.enhance.common.ClassMeta;

import static io.ebean.enhance.common.EnhanceConstants.INIT;
import static io.ebean.enhance.common.EnhanceConstants.NOARG_VOID;

/**
 * Adds a default constructor for the cases when there is not one already defined.
 */
class DefaultConstructor {

  /**
   * Adds a default constructor.
   */
  public static void add(ClassVisitor cw, ClassMeta classMeta) {

    if (classMeta.isLog(4)) {
      classMeta.log("... adding default constructor, super class: " + classMeta.getSuperClassName());
    }

    MethodVisitor underlyingMV = cw.visitMethod(Opcodes.ACC_PUBLIC, INIT, NOARG_VOID, null, null);

    ConstructorAdapter mv = new ConstructorAdapter(underlyingMV, classMeta, NOARG_VOID);

    mv.visitCode();
    Label l0 = new Label();
    mv.visitLabel(l0);
    mv.visitLineNumber(1, l0);
    mv.visitVarInsn(Opcodes.ALOAD, 0);
    mv.visitMethodInsn(Opcodes.INVOKESPECIAL, classMeta.getSuperClassName(), INIT, NOARG_VOID, false);
    Label l1 = new Label();
    mv.visitLabel(l1);
    mv.visitLineNumber(2, l1);
    mv.visitInsn(Opcodes.RETURN);

    Label l2 = new Label();
    mv.visitLabel(l2);
    mv.visitLocalVariable("this", "L" + classMeta.getClassName() + ";", null, l0, l2, 0);
    mv.visitMaxs(1, 1);
    mv.visitEnd();
  }
}