Question

我得到了一个基于switch语句的示例代码。我想要一些如何在arrayList或HashMap中添加它。另外，您认为哪种选择适合使用以及为什么会这样做？

public static final IFeatureExtraction create(final int piFeatureExtractionMethod, IPreprocessing poPreprocessing)
throws FeatureExtractionException
{
    IFeatureExtraction oFeatureExtraction = null;

    switch(piFeatureExtractionMethod)
    {
        case MARF.LPC:
            oFeatureExtraction = new LPC(poPreprocessing);
            break;

        case MARF.FFT:
            oFeatureExtraction = new FFT(poPreprocessing);
            break;

        case MARF.F0:
            oFeatureExtraction = new F0(poPreprocessing);
            break;

        case MARF.SEGMENTATION:
            oFeatureExtraction = new Segmentation(poPreprocessing);
            break;

        case MARF.CEPSTRAL:
            oFeatureExtraction = new Cepstral(poPreprocessing);
            break;

        case MARF.RANDOM_FEATURE_EXTRACTION:
            oFeatureExtraction = new RandomFeatureExtraction(poPreprocessing);
            break;

        case MARF.MIN_MAX_AMPLITUDES:
            oFeatureExtraction = new MinMaxAmplitudes(poPreprocessing);
            break;

        case MARF.FEATURE_EXTRACTION_PLUGIN:
        {
            try
            {
                oFeatureExtraction = (IFeatureExtraction)MARF.getFeatureExtractionPluginClass().newInstance();
                oFeatureExtraction.setPreprocessing(poPreprocessing);
            }
            catch(Exception e)
            {
                throw new FeatureExtractionException(e.getMessage(), e);
            }

            break;
        }

        case MARF.FEATURE_EXTRACTION_AGGREGATOR:
        {
            oFeatureExtraction = new FeatureExtractionAggregator(poPreprocessing);
            break;
        }

        default:
        {
            throw new FeatureExtractionException
            (
                "Unknown feature extraction method: " + piFeatureExtractionMethod
            );
        }
    }

    return oFeatureExtraction;
}

您认为可以应用任何其他模式吗？提及您推荐的模式名称。将欣赏额外的实施想法。

Answer 1

创建一个返回IFeatureExtraction实例的接口。使用Integer值作为Map的键，将该接口的实例添加到HashMap。您可以使用现有界面javax.inject.Provider。

，而不是创建自己的界面

public interface IFeatureExtractionProvider
{
    public IFeatureExtraction build(IPreprocessing poPreprocessing);
}

private final static Map<Integer, IFeatureExtractionProvider> map;

static
{
    map = new HashMap<Integer, IFeatureExtractionProvider>();
    map.put(MARF.LPC, new IFeatureExtractionProvider() {

        @Override
        public IFeatureExtraction build(IPreprocessing poPreprocessing) {
            return new LPC(poPreprocessing);
        }
    });

    // and so on...
}

public static final IFeatureExtraction create(final int piFeatureExtractionMethod, IPreprocessing poPreprocessing)
        throws FeatureExtractionException
{
    IFeatureExtractionProvider provider = map.get(piFeatureExtractionMethod);

    if (provider == null)
        throw new RuntimeException("no provider for " + piFeatureExtractionMethod);

    return provider.build(poPreprocessing);
}

虽然你没有提到Spring或IoC，但你确实要求提供更多的想法......而不是在静态初始化程序中构建IFeatureExtractionProvider的Map，你可以将它与像Spring这样的IoC框架结合起来。向界面添加新方法（public int getType()）。让您的框架将所有IFeatureExtractionProvider实例注入setter，然后根据getType()的值将其添加到地图中。

我们如何用arrayList替换switch语句？

1 个答案: