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GATEngine.java Go to the documentation of this file. package org.gridlab.gat.engine; import java.util.Hashtable; import java.util.Iterator; import java.util.StringTokenizer; import org.gridlab.gat.GATContext; import org.gridlab.gat.Preferences; import java.io.File; import java.io.IOException; import java.util.List; import java.util.Vector; import java.util.jar.Attributes; import java.util.jar.JarFile; import java.util.jar.Manifest; import org.gridlab.gat.io.cpi.FileCpi; import org.gridlab.gat.io.cpi.FileInputStreamCpi; import org.gridlab.gat.io.cpi.FileOutputStreamCpi; import org.gridlab.gat.io.cpi.LogicalFileCpi; import org.gridlab.gat.io.cpi.RandomAccessFileCpi; import org.gridlab.gat.resources.cpi.JobCpi; import org.gridlab.gat.resources.cpi.ResourceBrokerCpi; /** * @author rob */ /** * This class make the various GAT adaptors available to GAT */ public class GATEngine { protected static final boolean DEBUG = true; /** * This member variable holds reference to the single GATEngine */ private static GATEngine gatEngine = null; /** Keys are cpiClass names, elements are AdaptorSets. */ private Hashtable adaptors; /** * Constructs a default GATEngine instance */ protected GATEngine() { adaptors = new Hashtable(); readJarFiles(); } /** * Singleton method to construct a GATEngine * * @return A GATEngine instance */ public static synchronized GATEngine getGATEngine() { if (gatEngine == null) gatEngine = new GATEngine(); return gatEngine; } /** * Returns an instance of the specified XXXCpi class consistent with the * passed XXXCpi class name, preferences, and parameters * * @param cpiClass * The Cpi Class for which to look. * @param preferences * The Preferences used to construct the Cpi class. * @param parameters * The Parameters for the Cpi Constructor null means no * parameters. * @return The specified Cpi class or null if no such adaptor exists */ public Object getAdaptor(Class cpiClass, GATContext gatContext, Preferences preferences, Object[] tmpParams) { if(DEBUG) { System.err.println("getAdaptor: trying to get an adaptor for type " + cpiClass.getName()); } if (tmpParams == null) { tmpParams = new Object[0]; } if (preferences == null) { // No preferences. preferences = new Preferences(new Hashtable()); } // Add the context and the preferences as parameters Object[] parameters = new Object[tmpParams.length + 2]; parameters[0] = gatContext; parameters[1] = preferences; for (int i = 0; i < tmpParams.length; i++) { parameters[i + 2] = tmpParams[i]; } // Create an array with the parameter types Class[] parameterTypes = new Class[parameters.length]; for (int count = 0; count < parameterTypes.length; count++) { parameterTypes[count] = parameters[count].getClass(); } // Get an adaptor list for this type. AdaptorList l = (AdaptorList) adaptors.get(cpiClass.getName()); if (l == null) { // no adaptors for this type loaded. if(DEBUG) { System.err.println("No adaptors loaded for type " + cpiClass.getName()); } return null; } for (int i = 0; i < l.size(); i++) { Adaptor a = l.get(i); if (a.satisfies(preferences)) { Object o = a.newInstance(parameterTypes, parameters); if(o != null) { if(DEBUG) { System.err.println("Created adaptor instance of type " + a.getName()); } return o; } else { if (DEBUG) { System.err.println("Could not create an instance of Adaptor" + a.getName()); } } } } if(DEBUG) { System.err.println("None of the loaded adaptors satisfies the requested user preferences."); } return null; } /** * This method periodically populates the Map returned from a call to the * method getCpiClasses(). */ protected void readJarFiles() { // Obtain JarFiles in the optional directory that are GAT jars List jarFiles = getJarFiles(getOptionalPkgDirectory()); String adaptorPath = System.getProperty("gat.adaptor.path"); if(adaptorPath != null) { StringTokenizer st = new StringTokenizer(adaptorPath, File.pathSeparator); for(int i=0; i<st.countTokens(); i++) { String dir = st.nextToken(); List l = getJarFiles(dir); jarFiles.addAll(l); } } if(DEBUG) { System.err.println("List of GAT jar files is: "); printJars(jarFiles); } // Populate cpiClasses loadJarFiles(jarFiles); } protected void printJars(List l) { for(int i=0; i<l.size(); i++) { JarFile f = (JarFile) l.get(i); System.err.println(" " + f.getName()); } } /** * Gets the optional packages directories */ protected String getOptionalPkgDirectory() { return System.getProperty("java.home") + File.separator + "lib" + File.separator + "ext"; } /** * Obtains File's in the optional directory. */ protected List getFiles(File optionalPkgDirectory) { Vector vector = new Vector(); File[] files = optionalPkgDirectory.listFiles(); for (int count = 0; count < files.length; count++) vector.add(files[count]); return vector; } /** * Obtains JarFile's in the optional directory that are GAT jar's */ protected List getJarFiles(String dir) { File nextFile = null; JarFile jarFile = null; Manifest manifest = null; Attributes attributes = null; // Obtain files in the optional directory. List files = getFiles(new File(dir)); Iterator iterator = files.iterator(); Vector jarFiles = new Vector(); while (iterator.hasNext()) { nextFile = (File) iterator.next(); if (nextFile.isFile()) { try { jarFile = new JarFile(nextFile, true); manifest = jarFile.getManifest(); if (null != manifest) { attributes = manifest.getMainAttributes(); // If a GATAdaptor add to jarFiles if ("true".equals(attributes.getValue("GATAdaptor"))) { jarFiles.add(jarFile); } } } catch (IOException ioException) { // Ignore IOException } } } return jarFiles; } protected void loadCpiClass(Manifest manifest, Attributes attributes, String className, Class cpiClazz) { if(DEBUG) { System.err.println("Trying to load adaptor for " + className); } String attributeName = className + "Cpi-class"; // Get info for the adaptor String clazzString = attributes.getValue(attributeName); if (clazzString == null) { if(DEBUG) { System.err.println("Adaptor for " + className + " not found in Manifest"); } return; } if(DEBUG) { System.err.println("Adaptor for " + className + " found in Manifest, loading"); } Class clazz = null; try { clazz = Class.forName(clazzString); } catch (ClassNotFoundException e) { if(DEBUG) { System.err.println("Could not load Adaptor for " + className + ": " + e); } return; } if(DEBUG) { System.err.println("Adaptor for " + className + " loaded"); } Preferences preferences = new Preferences(attributes); Adaptor a = new Adaptor(cpiClazz, clazz, preferences); AdaptorList s = (AdaptorList) adaptors.get(cpiClazz.getName()); if (s == null) { s = new AdaptorList(cpiClazz); adaptors.put(cpiClazz.getName(), s); } s.addAdaptor(a); } protected void loadCPIClassesFromJar(JarFile jarFile) { Manifest manifest = null; Attributes attributes = null; // Get info for all adaptors try { manifest = jarFile.getManifest(); } catch (IOException e) { return; } attributes = manifest.getMainAttributes(); loadCpiClass(manifest, attributes, "File", FileCpi.class); loadCpiClass(manifest, attributes, "LogicalFile", LogicalFileCpi.class); loadCpiClass(manifest, attributes, "RandomAccessFile", RandomAccessFileCpi.class); loadCpiClass(manifest, attributes, "FileInputStream", FileInputStreamCpi.class); loadCpiClass(manifest, attributes, "FileOutputStream", FileOutputStreamCpi.class); loadCpiClass(manifest, attributes, "Job", JobCpi.class); loadCpiClass(manifest, attributes, "ResourceBroker", ResourceBrokerCpi.class); } /** * Populate cpiClasses */ protected void loadJarFiles(List jarFiles) { JarFile jarFile = null; Iterator iterator = jarFiles.iterator(); // Iterate over JarFiles while (iterator.hasNext()) { jarFile = (JarFile) iterator.next(); if(DEBUG) { System.err.println("loading adaptors from " + jarFile.getName()); } loadCPIClassesFromJar(jarFile); } } }