AbstractObjectManager.java

/*
 * AbstractObjectManager.java
 *
 * Created on 16 September 2003, 11:23
 */

package Sct;
import java.io.*;
import java.lang.reflect.*;

public abstract class AbstractObjectManager implements ObjectManager {
    
    public Streamable readObject(IStream s, String name)  throws IOException{
        String className = readClassName(s);
        return readObject(s, name, className);
    }
    
    public Streamable readObject(IStream s, String name, String className) throws IOException{
        Streamable ob = createObject(s, className);        
        return ob;
    }
    
    public void writeObject(OStream s, String name, Streamable object, boolean writeClassName) throws IOException{
        if (writeClassName) writeClassName(s,  object.getClassName());
        object.write(s, this);
    }
    
    
    protected Streamable createObject(IStream s, String className) throws IOException {
        ClassLoader cl = this.getClass().getClassLoader();
        try {                                    
            Class c = cl.loadClass(className);
                                       
            try {
                Class[] argTypes = {IStream.class, ObjectManager.class};
                Object[] args = {s, this};
                Method m = c.getMethod("read", argTypes);
                if (!m.isAccessible()) {
                    try {
                        m.setAccessible(true);
                    } catch (SecurityException se) {
                        InvalidClassException ie = new InvalidClassException(className, "No accessible static method for class: " + className);
                        ie.initCause(se);
                        throw ie;
                    }
                }
                return (Streamable)m.invoke(null, args);
            
            } catch (NoSuchMethodException e) {
                InvalidClassException ie = new InvalidClassException(className, "No appropriate constructor or static method for class: " + className);
                ie.initCause(e);
                throw ie;
            } 
            catch (IllegalAccessException e) {
                InvalidClassException ie = new InvalidClassException(className, "No appropriate static method for class: " + className);
                ie.initCause(e);
                throw ie;
            }
            catch (IllegalArgumentException e) {
                throw new Error("Internal bug creating object", e);                
            }            
            catch (NullPointerException e) {
                InvalidClassException ie = new InvalidClassException(className, "Method is not static for class: " + className);
                ie.initCause(e);
                throw ie;                
            }            
            catch (InvocationTargetException e) {
                if (e.getCause() instanceof IOException) throw (IOException)e.getCause();
                if (e.getCause() instanceof RuntimeException) throw (RuntimeException)e.getCause();                
                throw new Error("Bug creating: " + className + " - threw unexpected exception", e.getCause());            
            }                       
            
        } catch (ClassNotFoundException cnfe) { 
            InvalidClassException ie = new InvalidClassException(className, "Couldn't find class: " + className);
            ie.initCause(cnfe);
            throw ie;
        }
    }
    
    protected String readClassName(IStream in) throws IOException {
        String className = in.readString("ClassName");
        if (className.startsWith("SctClassName:")) {
            return Name.convertFromC(className.substring(13));
        } else {
            throw new InvalidClassException(className, "Stream does not contain a className");
        }
    }
    
    protected void writeClassName(OStream out, String className) throws IOException {
        out.writeString("ClassName", "SctClassName:"+ Name.convertToC(className));
    }
   
    
}

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