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/*  Copyright 1999 Vince Via [email protected]
    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/
package com.viaoa.comm.io;

import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectStreamClass;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.HashMap;

import com.viaoa.object.OAObject;
import com.viaoa.object.OAObjectPropertyDelegate;
import com.viaoa.util.Tuple;

/**
 * This is used to read an objectStream that has classes in it that no longer exist, or that
 * the package and/or class name have changed.
 * 
 * If the class does not exist anymore, then it will be replaced with an IODummy class, and ignored.
 *
 * @author vvia
 */
public class OAObjectInputStream extends ObjectInputStream {
    private HashMap hmReplace = new HashMap();
    private String oldPackageName, newPackageName;
    private HashMap hmReplaceName = new HashMap();

    public OAObjectInputStream(InputStream is) throws IOException {
        this(is, null, null);
    }
    
    public OAObjectInputStream(InputStream is, String oldPackageName) throws IOException {
        this(is, oldPackageName, oldPackageName);
    }

    /**
     * 
     * @param is
     * @param oldPackageName package name to look for.
     * @param newPackageName new package name to use, if null then it will use oldpackagename.
     * @throws IOException
     */
    public OAObjectInputStream(InputStream is, String oldPackageName, String newPackageName) throws IOException {
        super(is);
        enableResolveObject(true);
        this.oldPackageName = oldPackageName;
        if (newPackageName == null) newPackageName = oldPackageName;
        this.newPackageName = newPackageName;
    }
    
    public void replaceClassName(String oldName, String newName) {
        hmReplaceName.put(oldName, newName);
    }
    
    @Override
    protected Object resolveObject(Object obj) throws IOException {
        obj = super.resolveObject(obj);
        if (obj instanceof IODummy) {
            OAObjectPropertyDelegate.clearProperties((OAObject) obj);
        }
        return obj;
    }
    
    @Override
    protected ObjectStreamClass readClassDescriptor() throws IOException, ClassNotFoundException {
        ObjectStreamClass cd = super.readClassDescriptor();
        
        boolean bReplace = false;
        Field f = null;
        try {
            // 20200118
            String name = cd.getName();
            /* was:
            f = cd.getClass().getDeclaredField("name");
            f.setAccessible(true);
            String name = (String) f.get(cd);
            */
            String newName;
            if (oldPackageName != null) {
                if (!name.startsWith(oldPackageName)) return cd;
    
                String s = name.substring(oldPackageName.length()+1);
                newName = hmReplaceName.get(s);
                if (newName == null) newName = s;
                
                newName = newPackageName + "." + newName;

                f = cd.getClass().getDeclaredField("name");
                f.setAccessible(true);
                f.set(cd, newName);
            }
            else newName = name;
            
            Object objx = hmReplace.get(newName);
            
            if (objx == null) {
                hmReplace.put(newName, true);
                bReplace = true;
                Class c = Class.forName(newName);
                bReplace = false;
                hmReplace.put(newName, false);
            }
            else {
                bReplace = ((Boolean) objx).booleanValue();
            }
            
        }
        catch (Exception e) {
        }
        
        if (bReplace) {
            try {
                f.set(cd, IODummy.class.getName());
            }
            catch (Exception e2) {
                // TODO: handle exception
            }
        }
        return cd;
    }


}