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// This Source Code is in the Public Domain per: http://litesoft.org/License.txt package org.litesoft.bo.views; import org.litesoft.bo.views.caching.*; import org.litesoft.core.delayed.*; import org.litesoft.core.typeutils.*; import org.litesoft.core.util.*; public abstract class VoDataProvider<T extends IViewObject> extends AbstractCommonSupport { protected final VoMetaData<T> mMetaData; protected VoDataProvider( VoMetaData<T> pMetaData ) { Objects.assertNotNull( "VoMetaData", mMetaData = pMetaData ); } public VoMetaData<T> getMetaData() { return mMetaData; } public T insureInTS( T pInstance ) { return (pInstance.getTransactionSet() != null) ? pInstance : copyIntoNewTS( pInstance ); } @SuppressWarnings({"unchecked"}) public T copyIntoNewTS( T pInstance ) { return (T) pInstance.copyInto( createTransactionSet() ); } public TransactionSet createTransactionSet() { return ClientTransactionSet.create(); } abstract public void requestRow( ObjectURL pObjectURL, FetchRowDataProviderCallBack<T> pCallBack ); abstract public void requestRows( ObjectURL[] pObjectURLs, FetchRowsDataProviderCallBack<T> pCallBack ); abstract public void requestRows( BoAccessorFilters pFilters, FetchRowsDataProviderCallBack<T> pCallBack ); abstract public void requestAllRows( FetchRowsDataProviderCallBack<T> pCallBack ); abstract public void commit( TransactionSet pTransactionSet, CommitCallBack<T> pCallBack, ObjectURL... pReturnOnSuccess ); public void commit( T pInstance, CommitCallBack<T> pCallBack ) { commit( pInstance.getTransactionSet(), pCallBack, pInstance.getObjectURL() ); } public void requestTemporalTriggerPolling( TimedRunner pTimedRunner, boolean pFast ) { checkPollingRequest( autoPollingAllowed(), "" ); checkPollingRequest( !pFast || fastPollingAllowed(), "Fast " ); POLLER.start( pTimedRunner, this, pFast ); if ( pFast ) { requestTemporalTriggerPoll(); } } private void checkPollingRequest( boolean pFalseIsError, String pPrefix ) { if ( !pFalseIsError ) { throw new IllegalStateException( pPrefix + "Polling not supported for " + getForViewObjectRegisteredName() + "'s Data Provider" ); } } abstract protected String getForViewObjectRegisteredName(); public abstract void requestTemporalTriggerPoll(); protected boolean autoPollingAllowed() { return true; } protected boolean fastPollingAllowed() { return false; } protected void checkOnPolling() { POLLER.checkOnPolling( autoPollingAllowed(), fastPollingAllowed() ); } private static Poller POLLER = new Poller(); private static class Poller implements TemporalTriggerManager.AnyResponseListener, TimedRunnable { private boolean mPolling = false; private boolean mFast = false; private int mOutstandingRequests = 0; private long mLastMessageRecieved; private long mNextPollOnOrAfter; private VoDataProvider mDP; public void response() { if ( 0 == --mOutstandingRequests ) { if ( mPolling ) { mLastMessageRecieved = now(); } } } public void checkOnPolling( boolean pPollingAllowed, boolean pFastPollingAllowed ) { mOutstandingRequests++; if ( !pPollingAllowed ) { mPolling = false; } else if ( !pFastPollingAllowed ) { mFast = false; } } public void start( TimedRunner pTimedRunner, VoDataProvider pDP, boolean pFast ) { mDP = pDP; mFast = pFast; long zNow = now(); mLastMessageRecieved = zNow; // fool our self! long zDesiredOnOrAfter = zNow + getPollDelay(); if ( mPolling ) { // check if less than 2 Secs till next poll (this is the norm, otherwise > 2 Secs should only happen when switching from Slow to Fast) if ( (mNextPollOnOrAfter - zDesiredOnOrAfter) < 2000 ) { return; } pTimedRunner.cancel( this ); // Too long, stop current timed & start a shorter! } else { mPolling = true; } pTimedRunner.runOnOrAfter( this, setNextPollOnOrAfter( zDesiredOnOrAfter ) ); } public Again runOnce() { if ( !mPolling ) { return null; } long zNow = now(); long zPollDelay = getPollDelay(); long zDesiredOnOrAfter = mLastMessageRecieved + zPollDelay; // check if less than 2 Secs till the next poll should happen, happy case, Poll! if ( (zDesiredOnOrAfter - zNow) < 2000 ) { mDP.requestTemporalTriggerPoll(); zDesiredOnOrAfter = zNow + zPollDelay; } return new RunAgainOnOrAfter( setNextPollOnOrAfter( zDesiredOnOrAfter ) ); } private long setNextPollOnOrAfter( long zDesiredOnOrAfter ) { // System.out.println( "Next Poll In: " + (zDesiredOnOrAfter - now()) ); return (mNextPollOnOrAfter = zDesiredOnOrAfter); } private long now() { return UtilsCommon.nowTS().getTime(); } private long getPollDelay() { return mFast ? FAST_POLLING_DELAY : SLOW_POLLING_DELAY; } public static final int SLOW_POLLING_DELAY = 60000; // 1 Min public static final int FAST_POLLING_DELAY = 10000; // 10 Secs } } |