ASMSupport教程4.5 在Class中生成算术运算符
这节我们开始介绍ASMSupport如何生成算数运算符(+-\*/%),依旧先看我们需要生成的java代码：
package generated.operators;import java.io.PrintStream; import java.util.Random;
public class ArithmeticOperatorGenerateExample { static void printInt(String s, int i) { System.out.println(s + " = " + i); }
static void printFloat(String s, float f) { System.out.println(s + " = " + f); }
public static void main(String[] args) { Random rand = new Random(); int j = rand.nextInt(100) + 1; int k = rand.nextInt(100) + 1; printInt("j", j); printInt("k", k); int i = j + k; printInt("j + k", i); i = j - k; printInt("j - k", i); i = k / j; printInt("k / j", i); i = k * j; printInt("k * j", i); i = k % j; printInt("k % j", i); j %= k; printInt("j %= k", j); float v = rand.nextFloat(); float w = rand.nextFloat(); printFloat("v", v); printFloat("w", w); float u = v + w; printFloat("v + w", u); u = v - w; printFloat("v - w", u); u = v * w; printFloat("v * w", u); u = v / w; printFloat("v / w", u); u += v; printFloat("u += v", u); u -= v; printFloat("u -= v", u); u *= v; printFloat("u *= v", u); u /= v; printFloat("u /= v", u); } }
对应的代码如下，由于代码比较多，我们将对应的java代码写在asmsupport代码之上，便于对比。
package example.operators;import java.util.Random;
import org.objectweb.asm.Opcodes;
import jw.asmsupport.block.method.common.StaticMethodBody; import jw.asmsupport.clazz.AClass; import jw.asmsupport.clazz.AClassFactory; import jw.asmsupport.creator.ClassCreator; import jw.asmsupport.definition.value.Value; import jw.asmsupport.definition.variable.LocalVariable; import jw.asmsupport.operators.method.MethodInvoker; import jw.asmsupport.operators.numerical.arithmetic.Addition;
import example.AbstractExample;
public class ArithmeticOperatorGenerate extends AbstractExample {
/** * @param args */ public static void main(String[] args) { ClassCreator creator = new ClassCreator(Opcodes.V1_5, Opcodes.ACC_PUBLIC, "generated.operators.ArithmeticOperatorGenerateExample", null, null); //printIn方法 creator.createStaticMethod("printInt", new AClass[]{AClass.STRING_ACLASS, AClass.INT_ACLASS}, new String[]{"s", "i"}, null, null, 0, new StaticMethodBody(){ @Override public void generateBody(LocalVariable... argus) { invoke(systemOut, "println", append(argus[0], Value.value(" = "), argus[1])); runReturn(); } }); //printIn方法 creator.createStaticMethod("printFloat", new AClass[]{AClass.STRING_ACLASS, AClass.FLOAT_ACLASS}, new String[]{"s", "f"}, null, null, 0, new StaticMethodBody(){ @Override public void generateBody(LocalVariable... argus) { invoke(systemOut, "println", append(argus[0], Value.value(" = "), argus[1])); runReturn(); } }); creator.createStaticMethod("main", new AClass[] { AClassFactory.getProductClass(String[].class) }, new String[] { "args" }, null, null, Opcodes.ACC_PUBLIC + Opcodes.ACC_STATIC, new StaticMethodBody() { @Override public void generateBody(LocalVariable... argus) { //Random rand = new Random(); LocalVariable rand = createVariable("rand", AClassFactory.getProductClass(Random.class), false, invokeConstructor(AClassFactory.getProductClass(Random.class))); //rand.nextInt(100) + 1 Addition add1 = add(invoke(rand, "nextInt", Value.value(100)), Value.value(1)); //int j = rand.nextInt(100) + 1; LocalVariable j = createVariable("j", AClass.INT_ACLASS, false, add1); //int k = rand.nextInt(100) + 1; LocalVariable k = createVariable("k", AClass.INT_ACLASS, false, add1); //printInt("j", j); invokeStatic(getMethodOwner(), "printInt", Value.value("j"), j); //printInt("k", k); invokeStatic(getMethodOwner(), "printInt", Value.value("k"), k); //j + k Addition add2 = add(j, k); //int i = j + k; LocalVariable i = createVariable("i", AClass.INT_ACLASS, false, add2); //printInt("j + k", i); invokeStatic(getMethodOwner(), "printInt", Value.value("j + k"), i); //i = j - k; assign(i, sub(j, k)); //printInt("j - k", i); invokeStatic(getMethodOwner(), "printInt", Value.value("j - k"), i); //i = k / j; assign(i, div(k, j)); //printInt("k / j", i); invokeStatic(getMethodOwner(), "printInt", Value.value("k / j"), i); //i = k * j; assign(i, mul(k, j)); //printInt("k * j", i); invokeStatic(getMethodOwner(), "printInt", Value.value("k * j"), i); //i = k % j; assign(i, mod(k, j)); //printInt("k % j", i); invokeStatic(getMethodOwner(), "printInt", Value.value("k % j"), i); //j %= k; assign(j, mod(j, k)); //printInt("j %= k", j); invokeStatic(getMethodOwner(), "printInt", Value.value("j %= k"), j); //rand.nextFloat() MethodInvoker nextFloat = invoke(rand, "nextFloat"); //v = rand.nextFloat(); LocalVariable v = createVariable("v", AClass.FLOAT_ACLASS, false, nextFloat); //w = rand.nextFloat(); LocalVariable w = createVariable("w", AClass.FLOAT_ACLASS, false, nextFloat); //printFloat("v", v); invokeStatic(getMethodOwner(), "printFloat", Value.value("v"), v); //printFloat("w", w); invokeStatic(getMethodOwner(), "printFloat", Value.value("w"), w); //u = v + w; LocalVariable u = createVariable("u", AClass.FLOAT_ACLASS, false, add(v,w)); //printFloat("v + w", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("v + w"), u); //u = v - w; assign(u, sub(v, w)); //printFloat("v - w", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("v - w"), u); //u = v * w; assign(u, mul(v, w)); //printFloat("v * w", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("v * w"), u); //u = v / w; assign(u, div(v, w)); //printFloat("v / w", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("v / w"), u); //u += v; assign(u, add(u, v)); //printFloat("u += v", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("u += v"), u); //u -= v; assign(u, sub(u, v)); //printFloat("u -= v", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("u -= v"), u); //u *= v; assign(u, mul(u, v)); //printFloat("u *= v", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("u *= v"), u); //u /= v; assign(u, div(u, v)); //printFloat("u /= v", u); invokeStatic(getMethodOwner(), "printFloat", Value.value("u /= v"), u); runReturn(); } }); generate(creator); }}
这里我们不逐行解释，只对生成算术操作的方法进行解释：
- jw.asmsupport.block.ProgramBlock.add(Parameterized factor1, Parameterized factor2) ： 生成加法操作，生成的代码是factor1+factor2，返回类型jw.asmsupport.operators.numerical.arithmetic.Addition
- jw.asmsupport.block.ProgramBlock.sub(Parameterized factor1, Parameterized factor2) ： 生成减法操作，生成的代码是factor1-factor2 , 返回类型jw.asmsupport.operators.numerical.arithmetic.Subtraction
- jw.asmsupport.block.ProgramBlock.mul(Parameterized factor1, Parameterized factor2)： 生成乘法操作，生成的代码是factor1\*factor2 , 返回类型jw.asmsupport.operators.numerical.arithmetic.Multiplication
- jw.asmsupport.block.ProgramBlock.div(Parameterized factor1, Parameterized factor2)： 生成除法操作，生成的代码是factor1/factor2 , 返回类型jw.asmsupport.operators.numerical.arithmetic.Division
- jw.asmsupport.block.ProgramBlock.mod(Parameterized factor1, Parameterized factor2)：生成取模操作，生成的代码是factor1%factor2 , 返回类型jw.asmsupport.operators.numerical.arithmetic.Modulus
这些方法的返回值都是继承自jw.asmsupport.Parameterized接口的，这个接口意味着这个类还可以被其他的操作所使用，这个很容易理解，我可以将a+b这个运算作为参数传入某个方法，比如有个方法是c(int a),我们可以这样调用：c(a+b)。
