utility.java

java1.6众多例子参考

                                           ClassLoader relatedTypeClassLoader)
        throws ClassNotFoundException 
    {
        if (relatedType == null)
	    return Util.loadClass(className, remoteCodebase, loader);

	Class loadedClass = null;
	try {
	    loadedClass = Util.loadClass(className, remoteCodebase, loader);
	} catch (ClassNotFoundException cnfe) {
	    if (relatedType.getClassLoader() == null)
        	throw cnfe;
	}
	
        // If no class was not loaded, or if the loaded class is not of the 
	// correct type, make a further attempt to load the correct class
	// using the classloader of the related type.
	// _REVISIT_ Is this step necessary, or should the Util,loadClass
	// algorithm always produce a valid class if the setup is correct?
	// Does the OMG standard algorithm need to be changed to include
	// this step?
        if (loadedClass == null || 
	    (loadedClass.getClassLoader() != null &&
	     loadedClass.getClassLoader().loadClass(relatedType.getName()) != 
                 relatedType))
        {
            if (relatedType.getClassLoader() != relatedTypeClassLoader)
                throw new IllegalArgumentException(
                    "relatedTypeClassLoader not class loader of relatedType.");

            if (relatedTypeClassLoader != null)
		loadedClass = relatedTypeClassLoader.loadClass(className);
        }
	
	return loadedClass;
    }

    /**
     * Get the helper for an IDLValue
     *
     * Throws MARSHAL exception if no helper found.
     */
    public static BoxedValueHelper getHelper(Class clazz, String codebase, 
        String repId)
    {
	String className = null;
        if (clazz != null) {
	    className = clazz.getName();
	    if (codebase == null)
	        codebase = Util.getCodebase(clazz);
	} else {
	    if (repId != null) 
                className = RepositoryId.cache.getId(repId).getClassName();
	    if (className == null) // no repId or unrecognized repId
		throw wrapper.unableLocateValueHelper( 
		    CompletionStatus.COMPLETED_MAYBE);
	}

    	try {
            ClassLoader clazzLoader = 
                (clazz == null ? null : clazz.getClassLoader());
            Class helperClass = 
                loadClassForClass(className+"Helper", codebase, clazzLoader, 
                clazz, clazzLoader);
	    return (BoxedValueHelper)helperClass.newInstance();

    	} catch (ClassNotFoundException cnfe) {
	    throw wrapper.unableLocateValueHelper( CompletionStatus.COMPLETED_MAYBE,
		cnfe );
        } catch (IllegalAccessException iae) {
	    throw wrapper.unableLocateValueHelper( CompletionStatus.COMPLETED_MAYBE,
		iae );
        } catch (InstantiationException ie) {
	    throw wrapper.unableLocateValueHelper( CompletionStatus.COMPLETED_MAYBE,
		ie );
        } catch (ClassCastException cce) {
	    throw wrapper.unableLocateValueHelper( CompletionStatus.COMPLETED_MAYBE,
		cce );
        }    
    }

    /**
     * Get the factory for an IDLValue
     *
     * Throws MARSHAL exception if no factory found.
     */
    public static ValueFactory getFactory(Class clazz, String codebase, 
                               ORB orb, String repId)
    {
	ValueFactory factory = null;
	if ((orb != null) && (repId != null)) {
	    try {
                factory = ((org.omg.CORBA_2_3.ORB)orb).lookup_value_factory(
                    repId);
	    } catch (org.omg.CORBA.BAD_PARAM ex) {
	        // Try other way
	    }
	}

	String className = null;
        if (clazz != null) {
	    className = clazz.getName();
	    if (codebase == null)
	        codebase = Util.getCodebase(clazz);
	} else {
	    if (repId != null) 
                className = RepositoryId.cache.getId(repId).getClassName();
	    if (className == null) // no repId or unrecognized repId
		throw omgWrapper.unableLocateValueFactory( 
		    CompletionStatus.COMPLETED_MAYBE);
	}

	// if earlier search found a non-default factory, or the same default
	// factory that loadClassForClass would return, bale out now... 
	if (factory != null && 
	    (!factory.getClass().getName().equals(className+"DefaultFactory") ||
	     (clazz == null && codebase == null)))
	    return factory;

    	try {
            ClassLoader clazzLoader = 
                (clazz == null ? null : clazz.getClassLoader());
	    Class factoryClass = 
                loadClassForClass(className+"DefaultFactory", codebase,
                clazzLoader, clazz, clazzLoader);
	    return (ValueFactory)factoryClass.newInstance();

    	} catch (ClassNotFoundException cnfe) {
	    throw omgWrapper.unableLocateValueFactory( 
		CompletionStatus.COMPLETED_MAYBE, cnfe);
        } catch (IllegalAccessException iae) {
	    throw omgWrapper.unableLocateValueFactory( 
		CompletionStatus.COMPLETED_MAYBE, iae);
        } catch (InstantiationException ie) {
	    throw omgWrapper.unableLocateValueFactory( 
		CompletionStatus.COMPLETED_MAYBE, ie);
        } catch (ClassCastException cce) {
	    throw omgWrapper.unableLocateValueFactory( 
		CompletionStatus.COMPLETED_MAYBE, cce);
        }    
    }

    /*
     * Load an RMI-IIOP Stub given a Tie.
     * @param tie the tie.
     * @param stubClass the stub class. May be null.
     * @param remoteCodebase the codebase to use. May be null.
     * @param onlyMostDerived if true, will fail if cannot load a stub for the
     * first repID in the tie. If false, will walk all repIDs.
     * @return the stub or null if not found.
     */

    public static Remote loadStub(Tie tie,
				  PresentationManager.StubFactory stubFactory,
				  String remoteCodebase,
				  boolean onlyMostDerived) 
    {
        StubEntry entry = null;

        // Do we already have it cached?
        synchronized (tieToStubCache) {
            Object cached = tieToStubCache.get(tie);
            if (cached == null) {
                // No, so go try to load it...
                entry = loadStubAndUpdateCache(
                        tie, stubFactory, remoteCodebase, onlyMostDerived);
            } else {
                // Yes, is it a stub?  If not, it was a miss last
                // time, so return null again...
                if (cached != CACHE_MISS) {
                    // It's a stub.
                    entry = (StubEntry) cached;
                    
                    // Does the cached stub meet the requirements
                    // of the caller? If the caller does not require
                    // the most derived stub and does not require
                    // a specific stub type, we don't have to check
                    // any further because the cached type is good
                    // enough...
                    if (!entry.mostDerived && onlyMostDerived) {
                        // We must reload because we do not have
                        // the most derived cached already...
			// The stubFactory arg must be null here
			// to force onlyMostDerived=true to work
			// correctly.
                        entry = loadStubAndUpdateCache(tie,null,
			    remoteCodebase,true);
                    } else if (stubFactory != null && 
			!StubAdapter.getTypeIds(entry.stub)[0].equals( 
			    stubFactory.getTypeIds()[0]) )
                    {
                        // We do not have exactly the right stub. First, try to
                        // upgrade the cached stub by forcing it to the most
                        // derived stub...
                        entry = loadStubAndUpdateCache(tie,null,
			    remoteCodebase,true);

                        // If that failed, try again with the exact type
                        // we need...
                        if (entry == null) {
                            entry = loadStubAndUpdateCache(tie,stubFactory,
                                    remoteCodebase,onlyMostDerived);
                        }
                    } else {
                        // Use the cached stub. Is the delegate set?
                        try {
                            Delegate stubDel = StubAdapter.getDelegate(
				entry.stub ) ;
                        } catch (Exception e2) {
                            // No, so set it if we can...
                            try {            
                                Delegate del = StubAdapter.getDelegate(
				    tie ) ;
				StubAdapter.setDelegate( entry.stub,
				    del ) ;
                            } catch (Exception e) {}
                        }
                    }
                }
            }
        }
        
        if (entry != null) {
            return (Remote)entry.stub;
        } else {
            return null;
        }
    }
    
    /*
     * Load an RMI-IIOP Stub given a Tie, but do not look in the cache.
     * This method must be called with the lock held for tieToStubCache.
     * @param tie the tie.
     * @param stubFactory the stub factory. May be null.
     * @param remoteCodebase the codebase to use. May be null.
     * @param onlyMostDerived if true, will fail if cannot load a stub for the
     * first repID in the tie. If false, will walk all repIDs.
     * @return the StubEntry or null if not found.
     */
    private static StubEntry loadStubAndUpdateCache (
        Tie tie, PresentationManager.StubFactory  stubFactory,
	String remoteCodebase, boolean onlyMostDerived) 
    {
        org.omg.CORBA.Object stub = null;
        StubEntry entry = null;
        boolean tieIsStub = StubAdapter.isStub( tie ) ;

        if (stubFactory != null) {
            try {
                stub = stubFactory.makeStub();
            } catch (Throwable e) {
		wrapper.stubFactoryCouldNotMakeStub( e ) ;
                if (e instanceof ThreadDeath) {
                    throw (ThreadDeath) e;
                }
            }
        } else {
            String[] ids = null;
            if (tieIsStub) {
		ids = StubAdapter.getTypeIds( tie ) ;
            } else {
		// This will throw an exception if the tie
		// is not a Servant.  XXX Handle this better?
                ids = ((org.omg.PortableServer.Servant)tie).
                      _all_interfaces( null, null );
            }
                                
            if (remoteCodebase == null) {
                remoteCodebase = Util.getCodebase(tie.getClass());
            }
                    
	    if (ids.length == 0) {
		stub = new org.omg.stub.java.rmi._Remote_Stub();
	    } else {
		// Now walk all the RepIDs till we find a stub or fail...
		for (int i = 0; i < ids.length; i++) {
		    if (ids[i].length() == 0) {
			stub = new org.omg.stub.java.rmi._Remote_Stub();
			break;
		    }
			    
		    try {
			PresentationManager.StubFactoryFactory stubFactoryFactory =
			    com.sun.corba.se.spi.orb.ORB.getStubFactoryFactory();
			RepositoryId rid = RepositoryId.cache.getId( ids[i] ) ;
			String className = rid.getClassName() ;
			boolean isIDLInterface = rid.isIDLType() ;
			stubFactory = stubFactoryFactory.createStubFactory( 
			    className, isIDLInterface, remoteCodebase, null, 
			    tie.getClass().getClassLoader() ) ;
			stub = stubFactory.makeStub();
			break;
		    } catch (Exception e) {
			wrapper.errorInMakeStubFromRepositoryId( e ) ;
		    }
			    
		    if (onlyMostDerived) 
			break;
		}
	    }
	}
                
        if (stub == null) {
            // Stub == null, so cache the miss...
            tieToStubCache.put(tie,CACHE_MISS);
	} else {
            if (tieIsStub) {
                try {
		    Delegate del = StubAdapter.getDelegate( tie ) ;
		    StubAdapter.setDelegate( stub, del ) ;
                } catch( Exception e1 ) {
                    // The tie does not have a delegate set, so stash
                    // this tie away using the stub as a key so that
                    // later, when the stub is connected, we can find
                    // and connect the tie as well...
                
                    synchronized (stubToTieCache) {
                        stubToTieCache.put(stub,tie);
                    }
                }
            } else {
                // Tie extends Servant
                try {
		    Delegate delegate = StubAdapter.getDelegate( tie ) ;
		    StubAdapter.setDelegate( stub, delegate ) ;
                } catch( org.omg.CORBA.BAD_INV_ORDER bad) {
                    synchronized (stubToTieCache) {
                        stubToTieCache.put(stub,tie);
                    }