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由於性能差（高複雜度），我在一個大型java項目（移動應用程序）上工作，並得到了「感謝」的工作來審查和優化/重構代碼。 注：我對Java完全陌生（我的背景是C/C++），因此我爲任何愚蠢的問題applogize。 我做的第一件事就是使用Findbugs並修復所有報告的問題。之後，我使用了公制工具Understand來獲得概述，其中方法具有較高的圈複雜度。不幸的是，有很多方法的複雜度在2^20範圍以內： - （ 其中之一是我需要一些幫助或好點子...減少Cyclometic複雜性的方法
簡短說明： 對於與因此，編寫所有代碼的同事（單獨）實現了一個Serializable接口，其中包含一個名爲toByteArray()的方法。 例如，class Customer：class Customer：
class Customer
{
Address address;
AttributeCollection attributes;
LocationCollection locations;
int recId;
int recStatus;
DateTime recCreated;
String recCreatedBy;
String recCreatedByProg;
DateTime recChanged;
String recChangedBy;
String recChangedByProg;
int refAddressesId;
int refMandatorsId;
CustomerPropertyUsage usage;
/**
* Serialize the properties of a class into a byte array.
* @param destData Byte array, where the serialized data should be stored. Minimum 2 bytes.
* @param serializationIndex Offset within the passed byte array, from which the serialized data of the class
* should be entered. The offset is increased by the registered number of bytes so that after this method the
* next call points to the serialized data subsequent byte.
*/
void toByteArray(byte[] destData, IntClass serializationIndex)
{
if (this.address == null)
this.usage.value &= ~CustomerPropertyUsage.ADDRESS;
if (this.attributes == null)
this.usage.value &= ~CustomerPropertyUsage.ATTRIBUTES;
if (this.locations == null)
this.usage.value &= ~CustomerPropertyUsage.LOCATIONS;
this.usage.toByteArray(destData, serializationIndex);
CatrString catrString = null;
if ((this.usage.value & CustomerPropertyUsage.RECORD_HEADER) != CustomerPropertyUsage.NONE)
{
// Call static method getBytes from SerializationHelper class
SerializationHelper.getBytes(this.recId, 4, destData, serializationIndex.value);
serializationIndex.value += 4;
SerializationHelper.getBytes(this.recStatus, 4, destData, serializationIndex.value);
serializationIndex.value += 4;
// recChanged is a DateTime object. For the serialization we need minimum a 7 bytes array,
// Call method toByteArray() from DateTime class.
this.recChanged.toByteArray(destData, serializationIndex);
// call toByteArray of CatrString class
catrString = new CatrString(this.recChangedBy);
catrString.toByteArray(destData, serializationIndex);
catrString.setValue(this.recChangedByProg);
catrString.toByteArray(destData, serializationIndex);
// Same as recChanged
this.recCreated.toByteArray(destData, serializationIndex);
catrString = new CatrString(this.recCreatedBy);
catrString.toByteArray(destData, serializationIndex);
catrString.setValue(this.recCreatedByProg);
catrString.toByteArray(destData, serializationIndex);
SerializationHelper.getBytes(this.refAddressesId, 4, destData, serializationIndex.value);
serializationIndex.value += 4;
SerializationHelper.getBytes(this.refMandatorsId, 4, destData, serializationIndex.value);
serializationIndex.value += 4;
}
if (next property...)
{
... Serialization ...
}
if (next property...)
{
... Serialization ...
}
}
}
爲了保持GPRS會費低，t他的服務器在this.usage.value中設置了一個值，因此只有一個特定的屬性會被序列化並傳回服務器 - > 傳輸的消息很小。 這種方法會創建大量if-cases，具體取決於類中的屬性數量，因此路徑數量越來越高。 我認爲這不是一個美麗的解決方案，但它沒關係。我想要改變的是if內的序列化調用。 目前，他們是這樣的：
---- class SerializationHelper ----
static void getBytes(long valueToConvert, int numOfBytesToConvert, byte[] destinationBytes, int destinationBytesOffset)
{
destinationBytes[destinationBytesOffset] = (byte)(valueToConvert & 0x000000FF);
destinationBytes[destinationBytesOffset + 1] = (byte)((valueToConvert & 0x0000FF00) >> 8);
if (numOfBytesToConvert > 2)
{
destinationBytes[destinationBytesOffset + 2] = (byte)((valueToConvert & 0x00FF0000) >> 16);
destinationBytes[destinationBytesOffset + 3] = (byte)((valueToConvert & 0xFF000000) >> 24);
if (numOfBytesToConvert > 4)
{
destinationBytes[destinationBytesOffset + 4] = (byte)((valueToConvert & 0x000000FF00000000L) >> 32);
destinationBytes[destinationBytesOffset + 5] = (byte)((valueToConvert & 0x0000FF0000000000L) >> 40);
destinationBytes[destinationBytesOffset + 6] = (byte)((valueToConvert & 0x00FF000000000000L) >> 48);
destinationBytes[destinationBytesOffset + 7] = (byte)((valueToConvert & 0xFF00000000000000L) >> 56);
}
}
}
---- class CatrString ----
void toByteArray(byte[] destData, IntClass serializationIndex)
{
// Number of unicode characters
SerializationHelper.getBytes(this.textLength, 2, destData, serializationIndex.value);
serializationIndex.value += 2;
// Text UTF-16 unicode characters
for (int charIndex = 0; charIndex < this.textLength; charIndex++)
{
destData[serializationIndex.value] = (byte)(this.charCodes[charIndex] & 0x00FF);
serializationIndex.value++;
destData[serializationIndex.value] = (byte)((this.charCodes[charIndex] & 0xFF00) >> 8);
serializationIndex.value++;
}
// Code End of string as UTF-16 unicode character
destData[serializationIndex.value] = 0x00;
serializationIndex.value++;
destData[serializationIndex.value] = 0x00;
serializationIndex.value++;
}
---- class DateTime ----
void toByteArray(byte[] destData, IntClass serializationIndex)
{
destData[serializationIndex.value + 0] = (byte) (m_year % 0x0100); // year low-Byte.
destData[serializationIndex.value + 1] = (byte) (m_year/0x0100); // year high-Byte.
destData[serializationIndex.value + 2] = (byte) (m_month);
destData[serializationIndex.value + 3] = (byte) m_day;
destData[serializationIndex.value + 4] = (byte) m_hour;
destData[serializationIndex.value + 5] = (byte) m_minute;
destData[serializationIndex.value + 6] = (byte) m_second;
serializationIndex.value += 7;
}
應該可以寫一個更「一般」類，做所有的東西，系列化，在這裏我說的序列化XY 字節，就是這樣。但我不明白的是什麼「特殊」toByteArray()方法像字符串（UTF-16編碼） 或日期和時間？如果我將它們包裝在課堂上，那是一個很好的解決方案嗎？我有什麼收穫嗎？ Maintable代碼？高性能代碼？ 你會怎麼做？
Thx