Method.java

package task7.jvm.method;

import task7.jvm.attr.AttributeInfo;
import task7.jvm.attr.CodeAttr;
import task7.jvm.clz.ClassFile;
import task7.jvm.constant.ConstantPool;
import task7.jvm.constant.UTF8Info;
import task7.jvm.loader.ByteCodeIterator;

public class Method {
    private int accessFlag;
    private int nameIndex;
    private int descriptorIndex;

    private CodeAttr codeAttr;

    private ClassFile clzFile;


    public ClassFile getClzFile() {
        return clzFile;
    }

    public int getNameIndex() {
        return nameIndex;
    }

    public int getDescriptorIndex() {
        return descriptorIndex;
    }

    public CodeAttr getCodeAttr() {
        return codeAttr;
    }

    public void setCodeAttr(CodeAttr code) {
        this.codeAttr = code;
    }

    public Method(ClassFile clzFile, int accessFlag, int nameIndex, int descriptorIndex) {
        this.clzFile = clzFile;
        this.accessFlag = accessFlag;
        this.nameIndex = nameIndex;
        this.descriptorIndex = descriptorIndex;
    }


    public String toString() {

        ConstantPool pool = this.clzFile.getConstantPool();
        StringBuilder buffer = new StringBuilder();

        String name = ((UTF8Info) pool.getConstantInfo(this.nameIndex)).getValue();

        String desc = ((UTF8Info) pool.getConstantInfo(this.descriptorIndex)).getValue();

        buffer.append(name).append(":").append(desc).append("\n");

        buffer.append(this.codeAttr.toString(pool));

        return buffer.toString();
    }

    public static Method parse(ClassFile clzFile, ByteCodeIterator iter) {
        int accessFlag = iter.next2Bytes();
        int nameIndex = iter.next2Bytes();
        int descIndex = iter.next2Bytes();
        int attribCount = iter.next2Bytes();


        Method m = new Method(clzFile, accessFlag, nameIndex, descIndex);

        for (int j = 1; j <= attribCount; j++) {

            int attrNameIndex = iter.next2Bytes();
            String attrName = clzFile.getConstantPool().getUTF8String(attrNameIndex);
            iter.back(2);

            if (AttributeInfo.CODE.equalsIgnoreCase(attrName)) {
                CodeAttr codeAttr = CodeAttr.parse(clzFile, iter);
                m.setCodeAttr(codeAttr);
            } else {
                throw new RuntimeException("only CODE attribute is implemented , please implement the " + attrName);
            }

        }

        return m;

    }
}