java - 将 main() 添加到 Java 类时出现问题

Question

Java 新手，似乎无法在 Google 上找到这个简单问题的正确答案。

我正在使用遗传编程框架进行一些研究，并且一直在尝试根据我的需要定制他们的示例。定义主要功能是留给用户的，所以这就是我想要做的。

我正在尝试创建一个预先存在的类，使其成为可运行的文件。它扩展了更高级别的类来调用其他功能。

这是我遇到问题的代码(来自内置示例):

public class Multiplexer extends GPModel {
    public Multiplexer(final int noInputBits) {
      ...
    }

    ...
    public static void main(String[] args) {
        new Multiplexer(6).run();
    }  
}

这是我看到的错误。我使用 NetBeans 7.3.1 和 JDK 1.7。

Error: Main method not found in class org.epochx.gp.model.Multiplexer, please define the main method as: public static void main(String[] args) Java Result: 1 BUILD SUCCESSFUL (total time: 0 seconds)

这应该是相当微不足道的......我已经创建了具有 main 函数的其他类，并且没有遇到这个问题......它似乎只存在于框架内定义的预先存在的类中这个问题。

<小时/>

编辑

抱歉，封装类已经是公共(public)的，忘了提及。

<小时/>

Edit2 根据要求提供完整源代码...(epochx.org，如果有人感兴趣，v1.4.1)

package org.epochx.gp.model;

import java.util.*;

import org.epochx.epox.*;
import org.epochx.epox.bool.*;
import org.epochx.epox.lang.IfFunction;
import org.epochx.gp.representation.GPCandidateProgram;
import org.epochx.representation.CandidateProgram;
import org.epochx.tools.util.BoolUtils;

/**
 * GP model for the multiplexer problems.
 * 
 * <h4>Multiplexer problem</h4>
 * 
 * Given n binary inputValues, a program that solves the majority problem will
 * return true in all circumstances where a majority of the inputValues are true
 * (or 1), and return false whenever there is not a majority of true values.
 */
public class Multiplexer extends GPModel {

    // The names of the inputValues used in the grammar.
    private final Variable[] variables;

    // The boolean input sequences.
    private final boolean[][] inputValues;

    // No input bits.
    private int noAddressBits;
    private int noDataBits;

    /**
     * Constructs a Multiplexer model for the given number of inputs.
     * 
     * @param noInputBits the number of inputs the multiplexer problem should be
     *        for
     */
    public Multiplexer(final int noInputBits) {
        // Generate the input sequences.
        inputValues = BoolUtils.generateBoolSequences(noInputBits);

        // Calculate number of address/data bits.
        setBitSizes(noInputBits);

        // Define functions.
        final List<Node> syntax = new ArrayList<Node>();
        syntax.add(new IfFunction());
        syntax.add(new AndFunction());
        syntax.add(new OrFunction());
        syntax.add(new NotFunction());

        // Define terminal variables.
        variables = new Variable[noInputBits];
        // Add address inputs.
        for (int i = 0; i < noAddressBits; i++) {
            variables[i] = new Variable("a" + i, Boolean.class);
            syntax.add(variables[i]);
        }
        // Add data inputs.
        for (int i = noAddressBits; i < noInputBits; i++) {
            variables[i] = new Variable("d" + i, Boolean.class);
            syntax.add(variables[i]);
        }

        setSyntax(syntax);
    }

    /**
     * Calculates the fitness score for the given program. The fitness of a
     * program for the majority problem is calculated by evaluating it
     * using each of the possible sets of input values. There are
     * <code>2^noInputBits</code> possible sets of inputs. The fitness of the
     * program is the quantity of those input sequences that the program
     * returned an incorrect response for. That is, a fitness value of
     * <code>0.0</code> indicates the program responded correctly for every
     * possible set of input values.
     * 
     * @param p {@inheritDoc}
     * @return the calculated fitness for the given program.
     */
    @Override
    public double getFitness(final CandidateProgram p) {
        final GPCandidateProgram program = (GPCandidateProgram) p;

        double score = 0;

        // Execute on all possible inputs.
        for (final boolean[] in: inputValues) {

            // Set the variables.
            for (int i = 0; i < in.length; i++) {
                variables[i].setValue(in[i]);
            }

            if ((Boolean) program.evaluate() == multiplex(in)) {
                score++;
            }
        }

        return inputValues.length - score;
    }

    /*
     * Calculate and set the number of address and data bits.
     */
    private void setBitSizes(final int noInputBits) {
        noAddressBits = 1;
        while (true) {
            noDataBits = (int) Math.pow(2, noAddressBits);

            if ((noAddressBits + noDataBits) == noInputBits) {
                break;
            }

            noAddressBits++;
        }
    }

    /*
     * Calculate what the correct response should be for the given inputs.
     */
    private Boolean multiplex(final boolean[] vars) {
        // Calculate which data position to use.
        int dataPosition = 0;
        for (int i = 0; i < noAddressBits; i++) {
            if (vars[i]) {
                dataPosition += Math.pow(2, i);
            }
        }

        return vars[noAddressBits + dataPosition];
    }

    @Override
    public Class<?> getReturnType() {
        return Boolean.class;
    }


  public static void main(String[] args) {
        new Multiplexer(6).run();
    }  
}

Answer 1

我尝试了你的代码，对我来说很有效。尝试清理和构建...或者更轻松地创建一个新类 Test 并将 main 放在那里。