Grid Application Toolkit A simple API for Grid Applications

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ResourceBroker.java Go to the documentation of this file. package org.gridlab.gat.resources; import java.io.IOException; import java.util.List; import org.gridlab.gat.GATContext; import org.gridlab.gat.Preferences; import org.gridlab.gat.engine.GATEngine; import org.gridlab.gat.net.RemoteException; import org.gridlab.gat.resources.cpi.ResourceBrokerCpi; import org.gridlab.gat.util.TimePeriod; /** * An instance of this class is used to reserve resources. * <p> * A resource can either be a hardware resource or a software resource. A * software resource is simply an executable it makes little sense to reserve * such. Thus an instance of this class can currently only reserve a hardware * resource. * <p> * If one wishes to reserve a hardware resource, one must first describe the * hardware resource that one wishes to reserve. This is accomplished by * creating an instance of the class HardwareResourceDescription which describes * the hardware resource that one wishes to reserve. After creating such an * instance of the class HardwareResourceDescription that describes the hardware * resource one wishes to reserve, one must specify the time period for which * one wishes to reserve the hardware resource. This is accomplished by creating * an instance of the class TimePeriod which specifies the time period for which * one wishes to reserve the hardware resource. Finally, one must obtain a * reservation for the desired hardware resource for the desired time period. * This is accomplished by calling the method ReserveHardwareResource() on an * instance of the class ResourceBroker with the appropriate instance of * HardwareResourceDescription and the appropriate instance of TimePeriod. * <p> * In addition an instance of this class can be used to find hardware resources. * This is accomplished using the method FindHardwareResources(). This is * accomplished by creating an instance of the class HardwareResourceDescription * which describes the hardware resource that one wishes to find. After creating * such an instance of the class HardwareResourceDescription that describes the * hardware resource one wishes to find, one must find the corresponding * hardware resource. This is accomplished by calling the method * FindHardwareResources() on an instance of the class ResourceBroker with the * appropriate instance of HardwareResourceDescription. */ public abstract class ResourceBroker { protected GATContext gatContext; protected Preferences preferences; /** * This method constructs a ResourceBroker instance corresponding to the * passed GATContext. * * @param gatContext * A GATContext which will be used to broker resources * @param preferences * The Preferences for this instance * @throws java.lang.Exception * Thrown upon creation problems */ protected ResourceBroker(GATContext gatContext, Preferences preferences) throws Exception { this.gatContext = gatContext; this.preferences = preferences; } /** * This method constructs a ResourceBroker instance corresponding to the * passed GATContext. * * @param gatContext * A GATContext which will be used to broker resources * @param preferences * The Preferences for this instance * @throws java.lang.Exception * Thrown upon creation problems */ public ResourceBroker create(GATContext gatContext, Preferences preferences) throws Exception { GATEngine gatEngine = GATEngine.getGATEngine(); ResourceBrokerCpi r = (ResourceBrokerCpi) gatEngine.getAdaptor( ResourceBrokerCpi.class, gatContext, preferences, null); return r; } /** * Tests this ResourceBroker for equality with the passed Object. * <p> * If the given object is not a ResourceBroker, then this method immediately * returns false. * <p> * If the passed object is a ResourceBroker, then it is deemed equal if it * has an equivalent GATContext, as determined by the Equals method on * GATContext. * * @param object * The Object to test for equality * @return A boolean indicating equality */ public boolean equals(Object object) { if (false == (object instanceof ResourceBroker)) return false; return gatContext.equals(((ResourceBroker) object).gatContext); } /** * This method attempts to reserve the specified resource for the specified * time period. Upon reserving the specified resource this method returns a * Reservation. Upon failing to reserve the specified resource this method * returns an error. * * @param resourceDescription * A description, a ResourceDescription, of the hardware resource * to reserve * @param timePeriod * The time period, a TimePeriod , for which to reserve the * hardware resource * @throws RemoteException * Thrown upon problems accessing the remote instance * @throws java.io.IOException * Upon non-remote IO problem */ public abstract Reservation reserveResource( ResourceDescription resourceDescription, TimePeriod timePeriod) throws RemoteException, IOException; /** * This method attempts to reserve the specified resource for the specified * time period. Upon reserving the specified resource this method returns a * Reservation. Upon failing to reserve the specified resource this method * returns an error. * * @param resource * The resource to reserve. * @param timePeriod * The time period, a TimePeriod , for which to reserve the * hardware resource * @throws RemoteException * Thrown upon problems accessing the remote instance * @throws java.io.IOException * Upon non-remote IO problem */ public abstract Reservation reserveResource(Resource resource, TimePeriod timePeriod) throws RemoteException, IOException; /** * This method attempts to find one or more matching hardware resources. * Upon finding the specified hardware resource(s) this method returns a * java.util.List of HardwareResource instances. Upon failing to find the * specified hardware resource this method returns an error. * * @param resourceDescription * A description, a ResoucreDescription, of the resource(s) to * find * @return java.util.List of Resources upon success * @throws RemoteException * Thrown upon problems accessing the remote instance * @throws java.io.IOException * Upon non-remote IO problem */ public abstract List findResources(ResourceDescription resourceDescription) throws RemoteException, IOException; /** * This operation takes a JobDescription, and submits the specified job to * some underlying resource management or allocation system. On success, a * GATJob instance is returned, which represents the job. Upon failing to * submit the job, an error is issued. * * @param description * The job description. * @return @throws * RemoteException Thrown upon problems accessing the remote * instance * @throws IOException * Upon non-remote IO problem */ public abstract Job submitJob(JobDescription description) throws RemoteException, IOException; }