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com.backendless.FootprintsManager Maven / Gradle / Ivy
Android SDK used by developers to provide Backendless API in apps.
package com.backendless;
import com.backendless.exceptions.BackendlessException;
import weborb.reader.AnonymousObject;
import weborb.reader.ArrayType;
import weborb.reader.NamedObject;
import java.lang.reflect.Field;
import java.util.*;
/**
* If server sends object object with fields a, b, c
* and the client's class declares only fields a, b, then this class saves
* field c in memory in order to send it with the next user's request.
*/
public class FootprintsManager
{
private static final FootprintsManager instance = new FootprintsManager();
private static Set marked = new HashSet(); //for cyclic entities
public final Inner Inner = new Inner();
private final Map persistenceCache = new WeakHashMap();
private FootprintsManager()
{
}
static FootprintsManager getInstance()
{
return instance;
}
public Footprint getEntityFootprint( Object entity )
{
return persistenceCache.get( entity );
}
public String getObjectId( Object entity )
{
if( persistenceCache.containsKey( entity ) )
return getEntityFootprint( entity ).getObjectId();
return null;
}
public String getMeta( Object entity )
{
if( persistenceCache.containsKey( entity ) )
return getEntityFootprint( entity ).get__meta();
return null;
}
public Date getCreated( Object entity )
{
if( persistenceCache.containsKey( entity ) )
return getEntityFootprint( entity ).getCreated();
return null;
}
public Date getUpdated( Object entity )
{
if( persistenceCache.containsKey( entity ) )
return getEntityFootprint( entity ).getUpdated();
return null;
}
public class Inner
{
/**
* Puts missing properties like objectId, ___meta etc. into entity map.
*
* @param entity entity object
* @param entityMap entity map
*/
void putMissingPropsToEntityMap( Object entity, Map entityMap )
{
//to avoid endless recursion
if( marked.contains( entity ) )
return;
else
marked.add( entity );
//put objectId if exists in cache
if( !entityMap.containsKey( Footprint.OBJECT_ID_FIELD_NAME ) )
{
String objectId = getObjectId( entity );
if( objectId != null )
entityMap.put( Footprint.OBJECT_ID_FIELD_NAME, objectId );
}
//put __meta if exists in cache
if( !entityMap.containsKey( Footprint.META_FIELD_NAME ) )
{
String meta = getMeta( entity );
if( meta != null )
entityMap.put( Footprint.META_FIELD_NAME, meta );
}
/*
try
{
for( Object key : entityMap.keySet() )
{
Object value = entityMap.get( key );
//recursively restore inner objects' properties
if( value instanceof Map )
{
//get inner object
//looks for getter method and invokes it
Object entityField = entity.getClass().getField( (String) key ).get( entity );// new PropertyDescriptor( (String) key, entity.getClass() ).getReadMethod().invoke( entity );
putMissingPropsToEntityMap( entityField, (Map) value );
}
if( value instanceof Collection )
{
//get inner object collection
//looks for getter method and invokes it
Collection entityCollection = (Collection)entity.getClass().getField( (String) key ).get( entity );// new PropertyDescriptor( (String) key, entity.getClass() ).getReadMethod().invoke( entity );
//retrieve map collection
Collection mapCollection = (Collection) value;
//serialize every object in collection and put its missing properties
Iterator entityCollectionIterator = entityCollection.iterator();
Iterator mapCollectionIterator = mapCollection.iterator();
while( entityCollectionIterator.hasNext() )
{
putMissingPropsToEntityMap( entityCollectionIterator.next(), (Map) mapCollectionIterator.next() );
}
}
}
}
catch( NoSuchFieldException e )
{
throw new BackendlessException( e );
}
catch( IllegalAccessException e )
{
throw new BackendlessException( e );
}
finally
{
marked.remove( entity );
} */
}
/**
* When the object is created on server, client gets new instance of it. In order to remember the system fields
* (objectId, __meta etc.) it is required to duplicate the old instance in cache.
*
* @param serialized entity's map used to iterate through fields and duplicate footprints recursively
* @param newEntity entity from server
* @param oldEntity old entity (the one on which a method was called)
*/
void duplicateFootprintForObject( Map serialized, Object newEntity, Object oldEntity )
{
//to avoid endless recursion
if( marked.contains( newEntity ) )
return;
else
marked.add( newEntity );
try
{
//iterate through fields in the object and duplicate entities recursively
Set entries = serialized.entrySet();
for( Map.Entry entry : entries )
{
if( entry.getValue() instanceof Map )
{
//find read method for field and get object value
Object newEntityField = newEntity.getClass().getField( (String) entry.getKey() ).get( newEntity );// new PropertyDescriptor( (String) entry.getKey(), newEntity.getClass() ).getReadMethod().invoke( newEntity );
Object oldEntityField = oldEntity.getClass().getField( (String) entry.getKey() ).get( oldEntity );//new PropertyDescriptor( (String) entry.getKey(), oldEntity.getClass() ).getReadMethod().invoke( oldEntity );
duplicateFootprintForObject( (Map) entry.getValue(), newEntityField, oldEntityField );
}
else if( entry.getValue() instanceof Collection )
{
Collection newObjectCollection = (Collection) newEntity.getClass().getField( (String) entry.getKey() ).get( newEntity );// new PropertyDescriptor( (String) entry.getKey(), newEntity.getClass() ).getReadMethod().invoke( newEntity );
Collection oldObjectCollection = (Collection) oldEntity.getClass().getField( (String) entry.getKey() ).get( oldEntity );// new PropertyDescriptor( (String) entry.getKey(), oldEntity.getClass() ).getReadMethod().invoke( oldEntity );
Collection mapCollection = (Collection) entry.getValue();
Iterator newObjectCollectionIterator = newObjectCollection.iterator();
Iterator oldObjectCollectionIterator = oldObjectCollection.iterator();
Iterator mapCollectionIterator = mapCollection.iterator();
while( oldObjectCollectionIterator.hasNext() )
{
duplicateFootprintForObject( (Map) mapCollectionIterator.next(), newObjectCollectionIterator.next(), oldObjectCollectionIterator.next() );
}
}
}
Footprint footprint = persistenceCache.get( oldEntity );
if( footprint != null )
{
persistenceCache.put( newEntity, footprint );
}
}
catch( IllegalAccessException e )
{
throw new BackendlessException( e );
}
catch( NoSuchFieldException e )
{
throw new BackendlessException( e );
}
finally
{
marked.remove( newEntity );
}
}
/**
* Updates footprint for entity.
*
* @param serialized entity's map used to iterate through fields and update footprints recursively
* @param newEntity entity from server
* @param oldEntity entity on which a method was called (.save(), .create() etc.)
*/
void updateFootprintForObject( Map serialized, Object newEntity, Object oldEntity )
{
//to avoid endless recursion
if( marked.contains( newEntity ) )
return;
else
marked.add( newEntity );
try
{
//update footprints recursively
Set entries = serialized.entrySet();
for( Map.Entry entry : entries )
{
String key = (String) entry.getKey();
String upperKey = ((String) entry.getKey()).substring( 0, 1 ).toUpperCase().concat( ((String) entry.getKey()).substring( 1 ) );
if( entry.getValue() instanceof Map )
{
//find getter method and call it to get object property
Object newEntityField;
try
{
Field declaredField = newEntity.getClass().getDeclaredField( key );
declaredField.setAccessible( true );
newEntityField = declaredField.get( newEntity );//new PropertyDescriptor( (String) entry.getKey(), newEntity.getClass() ).getReadMethod().invoke( newEntity );
}
catch( NoSuchFieldException nfe )
{
//try to find field with first letter in uppercase
Field declaredField = newEntity.getClass().getDeclaredField( upperKey );
declaredField.setAccessible( true );
newEntityField = declaredField.get( newEntity );
}
Object oldEntityField;
try
{
Field declaredField = oldEntity.getClass().getDeclaredField( key );
declaredField.setAccessible( true );
oldEntityField = declaredField.get( oldEntity );//new PropertyDescriptor( (String) entry.getKey(), oldEntity.getClass() ).getReadMethod().invoke( oldEntity );
}
catch( NoSuchFieldException nfe )
{
//try to find field with first letter in uppercase
Field declaredField = oldEntity.getClass().getDeclaredField( upperKey );
declaredField.setAccessible( true );
oldEntityField = declaredField.get( oldEntity );
}
updateFootprintForObject( (Map) entry.getValue(), newEntityField, oldEntityField );
}
else if( entry.getValue() instanceof Collection )
{
Collection newObjectCollection;
try
{
Field declaredField = newEntity.getClass().getDeclaredField( key );
declaredField.setAccessible( true );
newObjectCollection = (Collection) declaredField.get( newEntity );//new PropertyDescriptor( (String) entry.getKey(), newEntity.getClass() ).getReadMethod().invoke( newEntity );
}
catch( NoSuchFieldException nfe )
{
//try to find field with first letter in uppercase
Field declaredField = newEntity.getClass().getDeclaredField( upperKey );
declaredField.setAccessible( true );
newObjectCollection = (Collection) declaredField.get( newEntity );
}
Collection oldObjectCollection;
try
{
Field declaredField = oldEntity.getClass().getDeclaredField( key );
declaredField.setAccessible( true );
oldObjectCollection = (Collection) declaredField.get( oldEntity );//new PropertyDescriptor( (String) entry.getKey(), oldEntity.getClass() ).getReadMethod().invoke( oldEntity );
}
catch( NoSuchFieldException nfe )
{
//try to find field with first letter in uppercase
Field declaredField = oldEntity.getClass().getDeclaredField( upperKey );
declaredField.setAccessible( true );
oldObjectCollection = (Collection) declaredField.get( oldEntity );
}
Collection mapCollection = (Collection) entry.getValue();
Iterator mapCollectionIterator = mapCollection.iterator();
Iterator oldObjectCollectionIterator = oldObjectCollection.iterator();
Iterator newObjectCollectionIterator = newObjectCollection.iterator();
while( oldObjectCollectionIterator.hasNext() )
{
updateFootprintForObject( (Map) mapCollectionIterator.next(), newObjectCollectionIterator.next(), oldObjectCollectionIterator.next() );
}
}
}
Footprint footprint = persistenceCache.get( newEntity );
persistenceCache.put( oldEntity, footprint );
removeFootprintForObject( serialized, newEntity );
}
catch( IllegalAccessException e )
{
throw new BackendlessException( e );
}
catch( NoSuchFieldException e )
{
throw new BackendlessException( e );
}
finally
{
marked.remove( newEntity );
}
}
/**
* Removes entity's footprint from cache.
*
* @param serialized entity's map used to iterate through fields and remove footprints recursively
* @param entity entity to be removed
*/
void removeFootprintForObject( Map serialized, Object entity )
{
//to avoid endless recursion
if( marked.contains( entity ) )
return;
else
marked.add( entity );
try
{
//iterate through object's properties and remove footprints recursively
Set entries = serialized.entrySet();
for( Map.Entry entry : entries )
{
if( entry.getValue() instanceof Map )
{
//find getter method and call it to retrieve object property
Object entityField = entity.getClass().getField( (String) entry.getKey() ).get( entity );//new PropertyDescriptor( (String) entry.getKey(), entity.getClass() ).getReadMethod().invoke( entity );
removeFootprintForObject( (Map) entry.getValue(), entityField );
}
else if( entry.getValue() instanceof Collection )
{
Collection objectCollection = (Collection) entity.getClass().getField( (String) entry.getKey() ).get( entity );//new PropertyDescriptor( (String) entry.getKey(), entity.getClass() ).getReadMethod().invoke( entity );
Collection mapCollection = (Collection) entry.getValue();
Iterator objectCollectionIterator = objectCollection.iterator();
Iterator mapCollectionIterator = mapCollection.iterator();
while( objectCollectionIterator.hasNext() )
{
removeFootprintForObject( (Map) mapCollectionIterator.next(), objectCollectionIterator.next() );
}
}
}
persistenceCache.remove( entity );
}
catch( IllegalAccessException e )
{
throw new BackendlessException( e );
}
catch( NoSuchFieldException e )
{
throw new BackendlessException( e );
}
finally
{
marked.remove( entity );
}
}
/**
* Puts saved entity's footprint to cache.
* Key - instance, value - footprint, initialized from instance.
* Footprint is just an object, containing only fields
* objectId, created, updated, meta.
*
* @param instance saved object received from server
* @param entity IAdaptingType
*/
public void putEntityFootprintToCache( Object instance, Object entity )
{
//to avoid endless recursion
if( marked.contains( entity ) )
return;
else
marked.add( entity );
try
{
if( instance instanceof BackendlessCollection )
{
AnonymousObject typedObject = (AnonymousObject) ((NamedObject) entity).getTypedObject();
ArrayType dataArray = (ArrayType) typedObject.getProperties().get( "data" );
Object[] instances = ((BackendlessCollection) instance).getCurrentPage().toArray();
putEntityFootprintToCache( instances, dataArray );
}
else if( entity instanceof NamedObject )
{
putEntityFootprintToCache( instance, ((NamedObject) entity).getTypedObject() );
}
else if( entity instanceof AnonymousObject )
{
putEntityFootprintToCache( instance, ((AnonymousObject) entity).getProperties() );
}
else if( entity instanceof ArrayType )
{
Object[] entities = (Object[]) ((ArrayType) entity).getArray();
Object[] arrayInstance = instance instanceof List ? ((List) instance).toArray() : (Object[]) instance;
for( int i = 0; i < arrayInstance.length; i++ )
putEntityFootprintToCache( arrayInstance[ i ], entities[ i ] );
}
else
{
Map e = (Map) entity;
for( Map.Entry entityEntry : e.entrySet() )
{
Object entityEntryValue = entityEntry.getValue();
if( entityEntryValue instanceof NamedObject || entityEntryValue instanceof ArrayType )
{
Object innerInstance = getObjectFieldByName( instance, entityEntry.getKey() );
putEntityFootprintToCache( innerInstance, entityEntry.getValue() );
}
}
Map cachedEntity = (Map) entity;
persistenceCache.put( instance, Footprint.initFromEntity( cachedEntity ) );
}
}
catch( Exception e )
{/*Error in caching process should not fail application*/
}
marked.remove( entity );
}
private Object getObjectFieldByName( Object instance,
String fieldName ) throws NoSuchFieldException, IllegalAccessException
{
Field field = instance.getClass().getDeclaredField( fieldName );
field.setAccessible( true );
return field.get( instance );
}
}
}
