Java tutorial
/* COPYRIGHT STATUS: Dec 1st 2001, Fermi National Accelerator Laboratory (FNAL) documents and software are sponsored by the U.S. Department of Energy under Contract No. DE-AC02-76CH03000. Therefore, the U.S. Government retains a world-wide non-exclusive, royalty-free license to publish or reproduce these documents and software for U.S. Government purposes. All documents and software available from this server are protected under the U.S. and Foreign Copyright Laws, and FNAL reserves all rights. Distribution of the software available from this server is free of charge subject to the user following the terms of the Fermitools Software Legal Information. Redistribution and/or modification of the software shall be accompanied by the Fermitools Software Legal Information (including the copyright notice). The user is asked to feed back problems, benefits, and/or suggestions about the software to the Fermilab Software Providers. 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Anyone downloading information from this server is obligated to secure any necessary Government licenses before exporting documents or software obtained from this server. */ package org.dcache.services.billing.db.impl; import com.google.common.base.Strings; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.util.Collection; import org.dcache.services.billing.db.IBillingInfoAccess; import org.dcache.services.billing.db.exceptions.RetryException; import org.dcache.services.billing.histograms.data.IHistogramData; /** * Framework for database access; composes delegate for handling inserts. * * @author arossi */ public abstract class BaseBillingInfoAccess implements IBillingInfoAccess { protected final Logger logger = LoggerFactory.getLogger(this.getClass()); private String delegateType; private QueueDelegate delegate; private int maxQueueSize; private int maxBatchSize; private boolean dropMessagesAtLimit; public void close() { if (delegate != null) { delegate.close(); } } public abstract void commit(Collection<IHistogramData> data) throws RetryException; public long getCommittedMessages() { if (delegate == null) { return 0; } return delegate.getCommitted(); } public long getDroppedMessages() { if (delegate == null) { return 0; } return delegate.getDropped(); } public long getInsertQueueSize() { if (delegate == null) { return 0; } return delegate.getQueueSize(); } public void initialize() { logger.debug("access type: {}", this.getClass().getName()); /* * can be null (configuration for read-only access; see #put()) */ if (delegateType != null) { Class<?> clzz; try { clzz = Class.forName(delegateType); } catch (ClassNotFoundException t) { throw new RuntimeException(t); } try { delegate = (QueueDelegate) clzz.newInstance(); } catch (InstantiationException | IllegalAccessException t) { throw new RuntimeException(t); } delegate.setDropMessagesAtLimit(dropMessagesAtLimit); delegate.setMaxQueueSize(maxQueueSize); delegate.setMaxBatchSize(maxBatchSize); delegate.setCallback(this); delegate.initialize(); logger.debug("delegate type: {}", clzz); } } public void put(IHistogramData data) { if (delegate == null) { logger.warn("attempting to insert data but database access has not" + " been initialized to handle inserts; please set the " + "billing.db.inserts.queue-delegate.type property"); return; } delegate.handlePut(data); } public void setDelegateType(String delegateType) { this.delegateType = Strings.emptyToNull(delegateType); } public void setDropMessagesAtLimit(boolean dropMessagesAtLimit) { this.dropMessagesAtLimit = dropMessagesAtLimit; } public void setMaxQueueSize(int maxQueueSize) { this.maxQueueSize = maxQueueSize; } public void setMaxBatchSize(int maxBatchSize) { this.maxBatchSize = maxBatchSize; } }