package task5.jvm.loader;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang3.StringUtils;
import task5.jvm.clz.ClassFile;
import java.io.*;
import java.util.ArrayList;
import java.util.List;
public class ClassFileLoader {
private List<String> clzPaths = new ArrayList<String>();
public byte[] readBinaryCode(String className) {
className = className.replace('.', File.separatorChar) +".class";
for(String path : this.clzPaths){
String clzFileName = path + File.separatorChar + className;
byte[] codes = loadClassFile(clzFileName);
if(codes != null){
return codes;
}
}
return null;
}
private byte[] loadClassFile(String clzFileName) {
File f = new File(clzFileName);
try {
return IOUtils.toByteArray(new FileInputStream(f));
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
public void addClassPath(String path) {
if(this.clzPaths.contains(path)){
return;
}
this.clzPaths.add(path);
}
public String getClassPath(){
return StringUtils.join(this.clzPaths,";");
}
public ClassFile loadClass(String className) {
byte[] codes = this.readBinaryCode(className);
ClassFileParser parser = new ClassFileParser();
return parser.parse(codes);
}
// ------------------------------backup------------------------
public String getClassPath_V1(){
StringBuffer buffer = new StringBuffer();
for(int i=0;i<this.clzPaths.size();i++){
buffer.append(this.clzPaths.get(i));
if(i<this.clzPaths.size()-1){
buffer.append(";");
}
}
return buffer.toString();
}
private byte[] loadClassFile_V1(String clzFileName) {
BufferedInputStream bis = null;
try {
File f = new File(clzFileName);
bis = new BufferedInputStream(new FileInputStream(f));
ByteArrayOutputStream bos = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int length = -1;
while((length = bis.read(buffer)) != -1){
bos.write(buffer, 0, length);
}
byte [] codes = bos.toByteArray();
return codes;
} catch(IOException e){
e.printStackTrace();
} finally{
if(bis != null){
try {
bis.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
return null;
}
}