Sending an Object through Socket

[sukatoa]

Good day,

I have an object, that contains a hashmap, that is dynamically utilized on client and server data transfer. that object may contain a string, an arraylist, or an object itself.

Based on the observation, i found out that, when the database will be reset, the client could still able to send the reliable data(through showing on the stream - println) but when the server received it, the essential list of data have lost.

What can you advice about this scenario?

Im looking forward to your replies experts :)

[Dököll]

Hey sukatoa!

Please post your code so we can have a closer look. Passers-by may also jump in if they have an idea what is happening through your code.

In a bit!

[sukatoa]

Here's the code

package com.data;

import java.io.File;
import java.io.Serializable;
import java.util.HashMap;

/**
 * This class is capable of handling objects represented in Key-Value pair where
 * the key is assumed to be unique for an accurate retrieve mechanism. This class
 * is serializable and can be passed to network using ObjectOutputStream.
 * <br><br>
 * @since SWF 1.3
 */
public class Properties implements Serializable {

    private HashMap<Object,Object> p = new HashMap<Object,Object>();
    private Boolean locked = new Boolean(false);

    /**
     * Default contructor: no objects are stored by default.
     */
    public Properties(){
        //
    }

    /**
     * Another contructor: receives a Map object that will be copied and used
     * as a reference for the default object handled in this instance
     * @param p Map object that contains desired properties to be handled by default.
     */
    public Properties(HashMap<Object,Object> p){
        this.p = p;
    }

    /**
     * This will add a property in this instance and checks if the key is already
     * exists or not in the pool of properties within this instance.
     * @param key unique object
     * @param value object that will be referred by the unique key.
     * @return true if the given key is unique, false otherwise.
     */
    public Boolean setProperty(Object key,Object value){
        if(!locked){
            if(!p.containsKey(key)){
                p.put(key, value);
                return true;
            }
        }
        return new Boolean(false);
    }

    /**
     * This will update a property in this instance and checks if the key is already
     * exists or not in the pool of properties within this instance.
     * @param key unique object
     * @param value object that will be referred by the unique key.
     * @return true if the given key exists, false otherwise.
     */
    public  Boolean updateProperty(Object key,Object value){
        if(!locked){
            if(p.containsKey(key)){
                p.put(key, value);
                return true;
            }
        }
        return new Boolean(false);
    }

    /**
     * Returns the value(object) under the given key.
     * @param key unique key existing in this instance
     * @return the value(object) under the given key, null if the key doesn't exists.
     */
    public  Object getValue(Object key){
        return p.get(key);
    }

    /**
     * Returns the key(object) that is referring to the given value(object). If 2 or more
     * value(object) are the same and existing in this instance, the first one will be returned.
     * @param value used as a reference to find the key(object) that refers to it.
     * @return the key(object) that refers to the given value, null if not existing
     */
    public  Object getKey(Object value){
        for(Object key:p.keySet()){
            if(p.get(key).equals(value)){
                return key;
            }
        }
        return null;
    }

    /**
     * Checks if the given key(object) exists within this instance.
     * @param key used to check for its existency.
     * @return true if exists, false otherwise.
     */
    public  Boolean isKeyExists(Object key){
        return new Boolean(p.containsKey(key));
    }

    /**
     * If invoked, all transactions that may modify the values inside of this instance
     * will be discarded
     */
    public void lock(){
        this.locked = new Boolean(true);
    }

    /**
     * If invoked, all transactions that may modify the values inside of this instance
     * will be granted
     */
    public void unlock(){
        this.locked = new Boolean(false);
    }

    /**
     * This Object(as an instance) will be persisted @ the specified file location given
     * @param loc filepath to be saved
     * @return true if successful, false otherwise
     */
    public Boolean persistProperties(File loc){
        return new PersistentObject().persistObject(p, loc);
    }

    /**
     * Replaces the current configuration and contents of this instance into an Object
     * that represents the same as this instance structure given the file location
     * @param loc where the file that represents an Object that is strictly the same with
     * this instance.
     * @return true if successful, false otherwise
     */
    public Boolean retrieveProperties(File loc){
        PersistentObject po = new PersistentObject();
        this.p = (HashMap<Object,Object>)po.retrieveObject(loc);
        return new Boolean(this.p!=null);
    }

    /**
     * Returns the container where the objects stored
     * @return the container represented in Map
     */
    public HashMap<Object,Object> getProperties(){
        return p;
    }

    /**
     * Replaces the current container with the given Map instance
     * @param p
     */
    public void setProperties(HashMap<Object,Object> p){
        this.p = p;
    }

    /**
     * Removes a specific object stored in the container handled by this instance
     * @param key that also holds the value
     */
    public void remove(Object key){
        this.p.remove(key);
    }

    /**
     * Cleans up the container: removes all objects that this instance is holding on
     */
    public void reset(){
        this.p.clear();
    }
}

[sukatoa]

i found an alternative one... since, it can carry an ArrayList referenced by a string...

Let say, setProperty("my list", ArrayList );
in the server side, the value of mylist will appear once, and the rest is empty...

I found an alternative, instead of using a list, i've used an array of object or an equivalent of ArrayList.toArr ay()... and now the server receives the reliable data... im confused,

setProperty("my list",Object[] datafromlist);

Why is this so?