ChangeObject.java

/**
 * Copyright (c) 2009 Farata Systems  http://www.faratasystems.com
 *
 * Licensed under The MIT License
 * Re-distributions of files must retain the above copyright notice.
 *
 * @license http://www.opensource.org/licenses/mit-license.php The MIT License
 *
 */
package clear.data;

import java.io.Serializable;
import java.lang.reflect.Field;
import java.util.*;

@SuppressWarnings("unchecked")
public class ChangeObject<T> implements Serializable {
	
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	public ChangeObject( ) {
		
	}

	public ChangeObject(T newObject, T oldObject ) {
		if ( newObject == null && oldObject == null) return;
		if ( newObject == null && oldObject != null) {
			state = 2;
			this.setPreviousVersion(oldObject);
		}
		if ( newObject != null && oldObject == null) {
			this.setNewVersion(newObject);
			state = 1;
		}
	}
	public void addChangedPropertyName(String propertyName) {
		if(!isUpdate()&&!isCreate()) throw new IllegalArgumentException("addChangedPropertyName applicable to update and create statuses only");
		// Allow identity changes from doCreate() methods, when initial changedNames is null
		if(changedPropertyNames == null)  changedPropertyNames=new String[]{};
        	
        for(int i = 0; i < changedPropertyNames.length; i++) {
           if(changedPropertyNames[i].equals(propertyName)) return;
        }    

        String tempChangedNames[] = new String[changedPropertyNames.length + 1];
        for(int i = 0; i < changedPropertyNames.length; i++) {
            tempChangedNames[i] = changedPropertyNames[i];
        }    

        tempChangedNames[changedPropertyNames.length] = propertyName;
        changedPropertyNames = tempChangedNames;
        changedPropertyValues = null; //getChangedValue will update the map
	}
	
	public void conflict(Object arg0) {
		// TODO Auto-generated method stub

	}

	public void conflict(Object arg0, boolean arg1) {
		// TODO Auto-generated method stub
	}
	
	public void fail() {
		state = 100;
	}

	public void fail(String desc) {
		// TODO Auto-generated method stub
		fail();
        error = desc;
	}
	
	public String[] getChangedPropertyNames() {
		return changedPropertyNames;

		// TODO offer default changedNames computation??
		/*
		if(changedPropertyNames == null) {
		if ((newVersion != null) && (previousVersion!=null)){
				if (newVersion instanceof ChangeSupport) {
					changedNames = ((ChangeSupport)newVersion).getChangedPropertyNames(previousVersion);
				}
			}
		}
		return changedNames;
		*/
	}
	
	@SuppressWarnings("rawtypes")
	public Map getChangedValues()
    {
    	if ((newVersion==null) || (previousVersion==null)) return null;
    	String [] changedNames = getChangedPropertyNames();
        
        changedPropertyValues = new HashMap();
        for(int i = 0; i < changedNames.length; i++)
        {
            String field = changedNames[i];
            changedPropertyValues.put(field, getNewValue(field));
        }      
        return Collections.unmodifiableMap(changedPropertyValues);
    }
	
    public String getError() {
    	return error;
    }
   
	public Object getObjectId() {
		// TODO Auto-generated method stub
		return null;
	}
	
	@SuppressWarnings("rawtypes")
	public Object getNewValue( String propertyName) {
		Object propertyValue = null;
//		if (newVersion instanceof ChangeSupport) {
//			if (newMap == null)
 //       		newMap = ((ChangeSupport)newVersion).getProperties();
//			propertyValue = newMap.get( propertyName);
//		} else {
			Class cls = newVersion.getClass();
			try {
			    Field field = cls.getField(propertyName);
			    propertyValue = field.get(newVersion);
			} catch (Exception e) {
				new RuntimeException("Unknown property '" + propertyName +"' for object of class " + cls.getName() );
			}
//		}
		return propertyValue;
	}
	
	@SuppressWarnings("rawtypes")
	public Object getPreviousValue(String propertyName) {
		Object propertyValue = null;
//		if (previousVersion instanceof ChangeSupport) {
//			if (previousMap == null)
//				previousMap = ((ChangeSupport)previousVersion).getProperties();
//			propertyValue = previousMap.get( propertyName);
//		} else {
			Class cls = previousVersion.getClass();
			try {
			    Field field = cls.getField(propertyName);
			    propertyValue = field.get(previousVersion);
			} catch (Exception e) {
				new RuntimeException("Unknown property '" + propertyName +"' for object of class " + cls.getName() );				
			}
//		}
		return propertyValue;	
	}
	
	
	public boolean isCreate() {
		return state == 1;
	}

	public boolean isDelete() {
		return state == 3;
	}
	
	public boolean isUpdate() {
		return state == 2;
	}

    public void setChangedPropertyNames(String [] columns)
    {
    	changedPropertyNames = (columns!=null)?columns:new String[]{};
    	changedPropertyValues = null;
    }
	
    public String error ="";
  	public void setError(String s) {
    	error = s;
    }
    
	public T getNewVersion() {
        return newVersion;
    }

	public T newVersion = null;
	public void setNewVersion(T obj) {
	    newVersion = obj; 
        changedPropertyValues = null;
	}
	
	public T previousVersion = null;
	public T getPreviousVersion() {
		return previousVersion;
	}
	public void setPreviousVersion(T obj) {
	    previousVersion = obj;
	}
	
	public int state = 0;
	public int getState() {
		return state;
	}
	public void setState(int s) {
		state = s;
	}
	public String id;
	public String getId() {
		return id;
	}
	public void setId(String newValue) {
		id = newValue;
	}
	
	public final String __type__="changeObject";
//---------------------- E X T E N S I O N S--------------------------
   

	private String[] changedPropertyNames = new String[] {};
	@SuppressWarnings({ "rawtypes" })
	transient private Map changedPropertyValues = null;
}