さまざまなコマンドを作成してさまざまなことを実行できるようにする、明確で簡潔なコードを作成するのに苦労しています。たとえば、私が取り組んでいる N 体シミュレーターでは、必要な機能は、ユーザーがまたはのようなコマンドを入力できることtele pos [x] [y] [z]ですtele celobj [celestial object name]。
これを行うには、スペースの位置に基づいて、入力文字列をトークンの配列に分割します。tele次に、最初の単語 ( ) が switch ステートメントの 1 つのレイヤーで処理され、2 番目の単語 (posまたはcelobj) が switch ステートメントの 2 番目のレイヤーで処理されるように、一連の switch ステートメントを使用します。その後、それに応じて次のトークンが処理されます。これらのさまざまな層すべてを通して、範囲外の例外を回避するために、ユーザーが有効な単語数を入力したことを確認します。
私のコードは正常に動作しますが、明らかに非常に読みにくく、複雑すぎます。役立つコードを探しているわけではありませんが、コマンド システムを整理したり、最適な方法でロジックを設定したりするための概念的な戦略を探しています。
念のためソースコードを含めましたが、私の説明が十分に明確であることを願っています.
public static void process(String cmd) {
String tokenNotFound = "Token not recognized...";
String notEnoughInfo = "Not enough info given. Please specify...";
String unableToParse = "Unable to parse number...";
String[] tokens = cmd.toLowerCase().split("\\s+");
switch (tokens[0]) {
case "close":
run = false;
break;
case "toggle":
if (tokens.length >= 2) {
switch (tokens[1]) {
case "render":
render = !render;
System.out.println("Render setting set to " + render);
break;
case "physics":
updatePhysics = !updatePhysics;
System.out.println("Physics update setting set to " + updatePhysics);
break;
case "trails":
showTrails = !showTrails;
System.out.println("Show trails setting set to " + showTrails);
break;
case "constellations":
showConstellations = !showConstellations;
System.out.println("Show constellations setting set to " + showConstellations);
break;
default:
System.err.println(tokenNotFound);
}
} else
System.err.println(notEnoughInfo);
break;
case "get":
if (tokens.length >= 2) {
switch (tokens[1]) {
case "fps":
System.out.println("FPS: " + realFPS);
break;
case "ups":
System.out.println("UPS: " + realUPS);
break;
case "cps":
System.out.println("CPS: " + realCPS);
break;
case "performance":
System.out.println("FPS: " + realFPS + " UPS: " + realUPS + " CPS: " + realCPS);
break;
case "time":
System.out.println(getTimestamp());
break;
case "celobj":
if (tokens.length >= 3) {
boolean objFound = false;
CelObj chosenObj = null;
for (CelObj celObj : physics.getCelObjs()) {
if (celObj.getName().toLowerCase().equals(tokens[2])) {
objFound = true;
chosenObj = celObj;
}
}
if (objFound) {
if (tokens.length >= 4) {
switch (tokens[3]) {
case "pos":
Vec3d pos = chosenObj.getCelPos();
System.out.println("POSITION: X= " + pos.x + " Y= " + pos.y + " Z= " + pos.z);
break;
case "vel":
Vec3d vel = chosenObj.getCelVel();
if (tokens.length >= 5 && tokens[4].equals("mag"))
System.out.println("VELOCITY: V= " + vel.magnitude());
else
System.out.println("VELOCITY: X= " + vel.x + " Y= " + vel.y + " Z= " + vel.z);
break;
case "mass":
System.out.println("MASS: M= " + chosenObj.getMass());
break;
case "radius":
System.out.println("RADIUS: R= " + chosenObj.getRadius());
break;
default:
System.err.println(notEnoughInfo);
}
} else
System.err.println(notEnoughInfo);
} else
System.err.println(tokenNotFound);
} else {
//Print list of celObjs
StringBuilder celObjNames = new StringBuilder("Celestial Objects: \n");
for (CelObj celObj : physics.getCelObjs()) {
celObjNames.append('\t').append(celObj.getName()).append('\n');
}
System.out.println(celObjNames.toString());
}
break;
default:
System.err.println(tokenNotFound);
}
} else
System.err.println(notEnoughInfo);
break;
case "set":
if (tokens.length >= 2) {
switch (tokens[1]) {
case "cps":
if (tokens.length >= 3) {
try {
int newCPS = parseInt(tokens[2]);
realTime_to_simTime = newCPS * timeInc;
System.out.println("Target CPS set to " + newCPS);
System.out.println("The simulation time is " + realTime_to_simTime + " times the speed of real time");
} catch (Exception e) {
System.err.println(unableToParse);
}
} else
System.err.println(notEnoughInfo);
break;
case "scale":
if (tokens.length >= 3) {
try {
scale = parseFloat(tokens[2]);
System.out.println("Render object scale is now set to " + scale);
} catch (Exception e) {
System.err.println(unableToParse);
}
} else
System.err.println(notEnoughInfo);
break;
case "speed":
if (tokens.length >= 3) {
try {
speed = parseFloat(tokens[2]);
System.out.println("Speed is now set to " + speed);
} catch (Exception e) {
System.err.println(unableToParse);
}
} else
System.err.println(notEnoughInfo);
break;
case "record":
if (tokens.length >= 4) {
if (tokens[3].equals("period")) {
try {
int newCPS = parseInt(tokens[2]);
realTime_to_simTime = newCPS * timeInc;
System.out.println("Target CPS set to " + newCPS);
System.out.println("The recording period is now every " + realTime_to_simTime + " seconds");
} catch (Exception e) {
System.err.println(unableToParse);
}
} else
System.err.println(tokenNotFound);
} else
System.err.println(notEnoughInfo);
break;
case "center":
if (tokens.length >= 3) {
boolean objFound = false;
CelObj chosenObj = null;
for (CelObj celObj : physics.getCelObjs()) {
if (celObj.getName().toLowerCase().equals(tokens[2])) {
objFound = true;
chosenObj = celObj;
}
}
if (objFound) {
centerCelObj = chosenObj;
System.out.println(chosenObj.getName() + " has been set as the center");
} else
System.err.println(tokenNotFound);
} else
System.err.println(notEnoughInfo);
break;
default:
System.err.println(tokenNotFound);
}
} else
System.err.println(notEnoughInfo);
break;
case "create":
//TODO:
break;
case "uncenter":
centerCelObj = null;
System.out.println("There is currently no center object");
break;
case "tele":
if (tokens.length >= 2) {
switch (tokens[1]) {
case "pos":
if (tokens.length >= 5) {
try {
double x = parseDouble(tokens[2]);
double y = parseDouble(tokens[3]);
double z = parseDouble(tokens[4]);
Vec3f cameraPos = new Vec3f((float) x, (float) y, (float) z);
//If camera is locked to an object, then translating the camera will only
//do so with respect to that planet
//Hence, the camera is translated back to world coordinates by translating it
//the negative of its locked celObj position vector
if (camera.getLockedCelObj() != null) {
cameraPos.translate(
new Vec3f(
camera.getLockedCelObj().getCelPos()
).negate()
);
}
camera.setPosition(multiply(worldunit_per_meters, cameraPos));
System.out.println("The camera position has been set to X= " + x + " Y= " + y + " Z= " + z);
} catch (Exception e) {
System.err.println(unableToParse);
}
} else
System.err.println(notEnoughInfo);
break;
case "celobj":
if (tokens.length >= 3) {
boolean objFound = false;
CelObj chosenObj = null;
for (CelObj celObj : physics.getCelObjs()) {
if (celObj.getName().toLowerCase().equals(tokens[2])) {
objFound = true;
chosenObj = celObj;
}
}
if (objFound) {
Vec3f celObjPos = new Vec3f(chosenObj.getCelPos());
Vec3f cameraPos = add(celObjPos, new Vec3f(0, (float) chosenObj.getRadius() * 2, 0));
//If camera is locked to an object, then translating the camera will only
//do so with respect to that planet
//Hence, the camera is translated back to world coordinates by translating it
//the negative of its locked celObj position vector
if (camera.getLockedCelObj() != null) {
cameraPos.translate(
new Vec3f(
camera.getLockedCelObj().getCelPos()
).negate()
);
}
//Make player 1 planet radius away from surface
camera.setPosition(multiply(worldunit_per_meters, cameraPos));
camera.setLookAt(multiply(worldunit_per_meters, celObjPos));
System.out.println("The camera position has been set to X= " + cameraPos.x + " Y= " + cameraPos.y + " Z= " + cameraPos.z);
} else
System.err.println(tokenNotFound);
} else
System.err.println(notEnoughInfo);
break;
default:
System.err.println(tokenNotFound);
}
} else
System.err.println(notEnoughInfo);
break;
case "lock":
if (tokens.length >= 2) {
boolean objFound = false;
CelObj chosenObj = null;
for (CelObj celObj : physics.getCelObjs()) {
if (celObj.getName().toLowerCase().equals(tokens[1])) {
objFound = true;
chosenObj = celObj;
}
}
if (objFound) {
camera.setLockedCelObj(chosenObj);
camera.setPosition(new Vec3f(0, 0, 0));
System.out.println("The camera has been locked to " + chosenObj.getName());
System.out.println("Type 'unlock' to revert back to unlocked status");
} else
System.err.println(tokenNotFound);
} else
System.err.println(notEnoughInfo);
break;
case "unlock":
String celObjName = camera.getLockedCelObj().getName();
//If camera is locked to an object, then translating the camera will only
//do so with respect to that planet
//Hence, the camera is translated back to world equivalent of where it is in
//that celObj's space by translating it the celObj's position
camera.setPosition(
add(
multiply(worldunit_per_meters,
(new Vec3f(camera.getLockedCelObj().getCelPos()))),
camera.getPosition()
)
);
camera.setLockedCelObj(null);
System.out.println("The camera has been unlocked from " + celObjName);
Vec3f pos = camera.getPosition();
System.out.println("The camera position has been set to X= " + pos.x + " Y= " + pos.y + " Z= " + pos.z);
break;
case "lookat":
if (tokens.length >= 3) {
switch (tokens[1]) {
case "celobj":
boolean objFound = false;
CelObj chosenObj = null;
for (CelObj celObj : physics.getCelObjs()) {
if (celObj.getName().toLowerCase().equals(tokens[2])) {
objFound = true;
chosenObj = celObj;
}
}
if (objFound) {
camera.setLookAt(new Vec3f(multiply(worldunit_per_meters, chosenObj.getCelPos())));
System.out.println("The camera is now looking at " + chosenObj.getName());
} else
System.err.println(tokenNotFound);
break;
}
} else
System.err.println(notEnoughInfo);
break;
default:
System.err.println(tokenNotFound);
}
}