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LogicalFile.java Go to the documentation of this file. package org.gridlab.gat.io; import java.io.IOException; import java.net.URI; import java.util.List; import org.gridlab.gat.GATContext; import org.gridlab.gat.Preferences; import org.gridlab.gat.engine.GATEngine; import org.gridlab.gat.io.cpi.LogicalFileCpi; import org.gridlab.gat.monitoring.Metric; import org.gridlab.gat.monitoring.MetricListener; import org.gridlab.gat.monitoring.Monitorable; import org.gridlab.gat.net.RemoteException; /** * An abstract representation of a set of identical physical files. * <p> * A LogicalFile is an abstract representation of a set of identical physical * files. This abstraction is useful for a number of reasons. For example, if * one wishes to replicate a physical file which is at one URI to a second URI. * Normally, one takes all the data at the first URI and replicates it to the * second URI even though the "network distance," between the first and second * URI may be great. A better solution to this problem is to have a set of * identical physical files distributed at different locations in "network * space." If one then wishes to replicate a physical file from one URI to a * second URI, GAT can then first determine which physical file is closest in * "network space" to the second URI, chose that physical file as the source * file, and copy it to the destination URI. Similarly, the construct of a * LogicalFile allows for migrating programs to, while at a given point in * "network space," use the closest physical file in "network space" to its * physical location. */ public abstract class LogicalFile implements Monitorable { protected URI location; protected GATContext gatContext; protected Preferences preferences; /** * This constructor creates a LogicalFile corresponding to the passed URI * instance and uses the passed GATContext to broker resources. * * @param location * The URI of one physical file in this LogicalFile * @param gatContext * The GATContext used to broker resources * @param preferences * The Preferences for this instance * @throws java.lang.Exception * Thrown upon creation problems */ protected LogicalFile(GATContext gatContext, Preferences preferences, URI location) throws IOException { this.location = location; this.gatContext = gatContext; this.preferences = preferences; } /** * This method creates a LogicalFile corresponding to the passed URI * instance and uses the passed GATContext to broker resources. * * @param location * The URI of one physical file in this LogicalFile * @param gatContext * The GATContext used to broker resources * @param preferences * The Preferences for this instance * @throws java.lang.Exception * Thrown upon creation problems */ public LogicalFile create(GATContext gatContext, URI location) throws Exception { return create(gatContext, null, location); } /** * This method creates a LogicalFile corresponding to the passed URI * instance and uses the passed GATContext to broker resources. * * @param location * The URI of one physical file in this LogicalFile * @param gatContext * The GATContext used to broker resources * @param preferences * The Preferences for this instance * @throws java.lang.Exception * Thrown upon creation problems */ public LogicalFile create(GATContext gatContext, Preferences preferences, URI location) throws Exception { GATEngine gatEngine = GATEngine.getGATEngine(); Object[] array = new Object[1]; array[0] = location; LogicalFileCpi f = (LogicalFileCpi) gatEngine.getAdaptor( LogicalFileCpi.class, gatContext, preferences, array); return f; } /** * Adds the passed File instance to the set of physical files represented by * this LogicalFile instance. * * @param file * A File instance to add to the set of physical files * represented by this LogicalFile instance. * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract void addFile(File file) throws RemoteException; /** * Adds the physical file at the passed URI to the set of physical files * represented by this LogicalFile instance. * * @param location * The URI of a physical file to add to the set of physical files * represented by this LogicalFile instance. * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract void addURI(URI location) throws RemoteException; /** * Removes the passed File instance from the set of physical files * represented by this LogicalFile instance. * * @param file * A File instance to remove from the set of physical files * represented by this LogicalFile instance. * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract void removeFile(File file) throws RemoteException; /** * Removes the physical file at the passed URI from the set of physical * files represented by this LogicalFile instance. * * @param location * The URI of a physical file to remove from the set of physical * files represented by this LogicalFile instance. * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract void removeURI(URI location) throws RemoteException; /** * Replicates the logical file represented by this instance to the physical * file specified by the passed URI. * * @param location * The URI of the new physical file * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance * @throws java.io.IOException * Upon non-remote IO problem */ public abstract void replicate(URI location) throws RemoteException, IOException; /** * Returns a java.util.List of URI instances each of which is the URI of a * physical file represented by this instance. * * @return The java.util.List of URIs * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract List getURIs() throws RemoteException; /** * Returns a java.util.List of File instances each of which is a File * corresponding to a physical file represented by this instance. * * @return The java.util.List of URIs * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract List getFiles() throws RemoteException; /** * This method adds the passed instance of a MetricListener to the * java.util.List of MetricListeners which are notified of MetricEvents by * an instance of this class. The passed MetricListener is only notified of * MetricEvents which correspond to Metric instance passed to this method. * * @param metricListener * The MetricListener to notify of MetricEvents * @param metric * The Metric corresponding to the MetricEvents for which the * passed MetricListener will be notified * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract void addMetricListener(MetricListener metricListener, Metric metric) throws RemoteException; /** * Removes the passed MetricListener from the java.util.List of * MetricListeners which are notified of MetricEvents corresponding to the * passed Metric instance. * * @param metricListener * The MetricListener to notify of MetricEvents * @param metric * The Metric corresponding to the MetricEvents for which the * passed MetricListener will be notified * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract void removeMetricListener(MetricListener metricListener, Metric metric) throws RemoteException; /** * This method returns a java.util.List of Metric instances. Each Metric * instance in this java.util.List is a Metric which can be monitored on * this instance. * * @return An java.util.List of Metric instances. Each Metric instance in * this java.util.List is a Metric which can be monitored on this * instance. * @throws java.rmi.RemoteException * Thrown upon problems accessing the remote instance */ public abstract List getMetrics() throws RemoteException; }