ASMSupport教程4.8 生成逻辑运算操作
在java中有以下逻辑运算符：
- &&：条件与
- ||：条件或
- & : 布尔型的逻辑与
- | ： 布尔型的逻辑或
- ^ : 布尔型的逻辑异或
- ! : 非操作
那么接下来我们将些段例子来看看各种逻辑运算的效果，并且我们再通过ASMSupport生成这个例子的字节码Class：
public static void main(String[] args) {
// create truth table for && (conditional AND) operator
System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Conditional AND (&&)",
"false && false",
(false && false),
"false && true",
(false && true),
"true && false",
(true && false),
"true && true",
(true && true));
// create truth table for || (conditional OR) operator
System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Conditional OR (||)", "false || false", (false || false),
"false || true", (false || true), "true || false",
(true || false), "true || true", (true || true));
// create truth table for & (boolean logical AND) operator
System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Boolean logical AND (&)", "false & false", (false & false),
"false & true", (false & true), "true & false", (true & false),
"true & true", (true & true));
// create truth table for | (boolean logical inclusive OR) operator
System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Boolean logical inclusive OR (|)", "false | false",
(false | false), "false | true", (false | true),
"true | false", (true | false), "true | true", (true | true));
// create truth table for ^ (boolean logical exclusive OR) operator
System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Boolean logical exclusive OR (^)", "false ^ false",
(false ^ false), "false ^ true", (false ^ true),
"true ^ false", (true ^ false), "true ^ true", (true ^ true));
// create truth table for ! (logical negation) operator
System.out.printf("%s\n%s: %b\n%s: %b\n", "Logical NOT (!)", "!false",
(!false), "!true", (!true));
}
我们接下来使用ASMSupport如何生成上面的代码:
package example.operators;
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 example.AbstractExample;
public class LogicalOperatorGenerate extends AbstractExample {
public static void main(String[] args) {
//willGenerate(args);
ClassCreator creator = new ClassCreator(Opcodes.V1_5,
Opcodes.ACC_PUBLIC,
"generated.operators.LogicalOperatorGenerateExample", null,
null);
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) {
/*System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Conditional AND (&&)", "false && false", (false && false),
"false && true", (false && true), "true && false",
(true && false), "true && true", (true && true));*/
invoke(systemOut, "printf",
Value.value("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n"),
Value.value("Conditional AND (&&)"),
Value.value("false && false"),
conditionalAnd(Value.value(false), Value.value(false)),
Value.value("false && true"),
conditionalAnd(Value.value(false), Value.value(true)),
Value.value("true && false"),
conditionalAnd(Value.value(true), Value.value(false)),
Value.value("true && true"),
conditionalAnd(Value.value(true), Value.value(true))
);
/*System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Conditional OR (||)", "false || false", (false || false),
"false || true", (false || true), "true || false",
(true || false), "true || true", (true || true));*/
invoke(systemOut, "printf",
Value.value("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n"),
Value.value("Conditional OR (||)"),
Value.value("false || false"), conditionalOr(Value.value(false), Value.value(false)),
Value.value("false || true"), conditionalOr(Value.value(false), Value.value(true)),
Value.value("true || false"), conditionalOr(Value.value(true), Value.value(false)),
Value.value("true || true"), conditionalOr(Value.value(true), Value.value(true))
);
/*System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Boolean logical AND (&)", "false & false", (false & false),
"false & true", (false & true), "true & false", (true & false),
"true & true", (true & true));*/
invoke(systemOut, "printf",
Value.value("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n"),
Value.value("Boolean logical AND (&)"),
Value.value("false & false"), logicalAnd(Value.value(false), Value.value(false)),
Value.value("false & true"), logicalAnd(Value.value(false), Value.value(true)),
Value.value("true & false"), logicalAnd(Value.value(true), Value.value(false)),
Value.value("true & true"), logicalAnd(Value.value(true), Value.value(true))
);
/*System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Boolean logical inclusive OR (|)", "false | false",
(false | false), "false | true", (false | true),
"true | false", (true | false), "true | true", (true | true));*/
invoke(systemOut, "printf",
Value.value("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n"),
Value.value("Boolean logical inclusive OR (|)"),
Value.value("false | false"), logicalOr(Value.value(false), Value.value(false)),
Value.value("false | true"), logicalOr(Value.value(false), Value.value(true)),
Value.value("true | false"), logicalOr(Value.value(true), Value.value(false)),
Value.value("true | true"), logicalOr(Value.value(true), Value.value(true))
);
/*System.out.printf("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n",
"Boolean logical exclusive OR (^)", "false ^ false",
(false ^ false), "false ^ true", (false ^ true),
"true ^ false", (true ^ false), "true ^ true", (true ^ true));*/
invoke(systemOut, "printf",
Value.value("%s\n%s: %b\n%s: %b\n%s: %b\n%s: %b\n\n"),
Value.value("Boolean logical exclusive OR (^)"),
Value.value("false ^ false"), logicalXor(Value.value(false), Value.value(false)),
Value.value("false ^ true"), logicalXor(Value.value(false), Value.value(true)),
Value.value("true ^ false"), logicalXor(Value.value(true), Value.value(false)),
Value.value("true ^ true"), logicalXor(Value.value(true), Value.value(true))
);
/*System.out.printf("%s\n%s: %b\n%s: %b\n", "Logical NOT (!)", "!false",
(!false), "!true", (!true));*/
invoke(systemOut, "printf",
Value.value("%s\n%s: %b\n%s: %b\n"),
Value.value("Logical NOT (!)"),
Value.value("!false"), not(Value.value(false)),
Value.value("!true"), not(Value.value(true))
);
runReturn();
}
});
generate(creator);
}
}
我们在每段ASMSupport的代码上分别用注释说明了这段代码生成的内容是什么，我们就不对其进行详细的解说，在这只说明下这些逻辑运算符所对应的asmsupport方法，这些方法都是存在与jw.asmsupport.block.ProgramBlock类中：
- public ShortCircuitAnd conditionalAnd(Parameterized factor1, Parameterized factor2) : 条件与(&&)操作
- public ShortCircuitOr conditionalOr(Parameterized factor1, Parameterized factor2) : 条件或(||)操作
- public LogicalAnd logicalAnd(Parameterized factor1, Parameterized factor2) : 逻辑与(&)操作
- public LogicalOr logicalOr(Parameterized factor1, Parameterized factor2) : 逻辑或(|)操作
- public LogicalXor logicalXor(Parameterized factor1, Parameterized factor2) ： 逻辑异或(^)操作
- public Not not(Parameterized factor) : 非(!)操作
以上除了not方法都有两个参数，分别表示运算符前后的两个参数。比如a&&b，那么factor1表示a，factor2表示b, 至于not方法，其效果就是!factor的效果。
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