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author | slaws <slaws@13f79535-47bb-0310-9956-ffa450edef68> | 2010-11-02 13:01:07 +0000 |
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committer | slaws <slaws@13f79535-47bb-0310-9956-ffa450edef68> | 2010-11-02 13:01:07 +0000 |
commit | 54dcf777e655a94049d8000f8f7b15846f1d54e6 (patch) | |
tree | a2cc990cf48e1377396b975fff9855ecfd18f1e0 /sca-java-2.x/tags/2.0-Beta1-RC2/modules/sca-api/src/main/java/org/oasisopen/sca/client/impl/SCAClientFactoryFinderImpl.java | |
parent | cab9e5e0c2ee4bd15ba65625fd9ff75ced777c75 (diff) |
Tag for 2.0-Beta1-RC2
git-svn-id: http://svn.us.apache.org/repos/asf/tuscany@1030026 13f79535-47bb-0310-9956-ffa450edef68
Diffstat (limited to 'sca-java-2.x/tags/2.0-Beta1-RC2/modules/sca-api/src/main/java/org/oasisopen/sca/client/impl/SCAClientFactoryFinderImpl.java')
-rw-r--r-- | sca-java-2.x/tags/2.0-Beta1-RC2/modules/sca-api/src/main/java/org/oasisopen/sca/client/impl/SCAClientFactoryFinderImpl.java | 289 |
1 files changed, 289 insertions, 0 deletions
diff --git a/sca-java-2.x/tags/2.0-Beta1-RC2/modules/sca-api/src/main/java/org/oasisopen/sca/client/impl/SCAClientFactoryFinderImpl.java b/sca-java-2.x/tags/2.0-Beta1-RC2/modules/sca-api/src/main/java/org/oasisopen/sca/client/impl/SCAClientFactoryFinderImpl.java new file mode 100644 index 0000000000..0f5eae7603 --- /dev/null +++ b/sca-java-2.x/tags/2.0-Beta1-RC2/modules/sca-api/src/main/java/org/oasisopen/sca/client/impl/SCAClientFactoryFinderImpl.java @@ -0,0 +1,289 @@ +/* + * Copyright(C) OASIS(R) 2005,2010. All Rights Reserved. + * OASIS trademark, IPR and other policies apply. + */ +package org.oasisopen.sca.client.impl; + +import org.oasisopen.sca.client.SCAClientFactoryFinder; + +import java.io.BufferedReader; +import java.io.Closeable; +import java.io.IOException; +import java.io.InputStream; +import java.io.InputStreamReader; +import java.lang.reflect.Constructor; +import java.net.URI; +import java.net.URL; +import java.util.Properties; + +import org.oasisopen.sca.NoSuchDomainException; +import org.oasisopen.sca.ServiceRuntimeException; +import org.oasisopen.sca.client.SCAClientFactory; + +/** + * This is a default implementation of an SCAClientFactoryFinder which is + * used to find an implementation of the SCAClientFactory interface. + * + * @see SCAClientFactoryFinder + * @see SCAClientFactory + * + * @author OASIS Open + */ +public class SCAClientFactoryFinderImpl implements SCAClientFactoryFinder { + + /** + * The name of the System Property used to determine the SPI + * implementation to use for the SCAClientFactory. + */ + private static final String SCA_CLIENT_FACTORY_PROVIDER_KEY = + SCAClientFactory.class.getName(); + + /** + * The name of the file loaded from the ClassPath to determine + * the SPI implementation to use for the SCAClientFactory. + */ + private static final String SCA_CLIENT_FACTORY_PROVIDER_META_INF_SERVICE + = "META-INF/services/" + SCA_CLIENT_FACTORY_PROVIDER_KEY; + + /** + * Public Constructor + */ + public SCAClientFactoryFinderImpl() { + } + + /** + * Creates an instance of the SCAClientFactorySPI implementation. + * This discovers the SCAClientFactorySPI Implementation and instantiates + * the provider's implementation. + * + * @param properties Properties that may be used when creating a new + * instance of the SCAClient + * @param classLoader ClassLoader that may be used when creating a new + * instance of the SCAClient + * @return new instance of the SCAClientFactory + * @throws ServiceRuntimeException Failed to create SCAClientFactory + * Implementation. + */ + public SCAClientFactory find(Properties properties, + ClassLoader classLoader, + URI domainURI ) + throws NoSuchDomainException, ServiceRuntimeException { + if (classLoader == null) { + classLoader = getThreadContextClassLoader (); + } + final String factoryImplClassName = + discoverProviderFactoryImplClass(properties, classLoader); + final Class<? extends SCAClientFactory> factoryImplClass + = loadProviderFactoryClass(factoryImplClassName, + classLoader); + final SCAClientFactory factory = + instantiateSCAClientFactoryClass(factoryImplClass, + domainURI ); + return factory; + } + + /** + * Gets the Context ClassLoader for the current Thread. + * + * @return The Context ClassLoader for the current Thread. + */ + private static ClassLoader getThreadContextClassLoader () { + final ClassLoader threadClassLoader = + Thread.currentThread().getContextClassLoader(); + return threadClassLoader; + } + + /** + * Attempts to discover the class name for the SCAClientFactorySPI + * implementation from the specified Properties, the System Properties + * or the specified ClassLoader. + * + * @return The class name of the SCAClientFactorySPI implementation + * @throw ServiceRuntimeException Failed to find implementation for + * SCAClientFactorySPI. + */ + private static String + discoverProviderFactoryImplClass(Properties properties, + ClassLoader classLoader) + throws ServiceRuntimeException { + String providerClassName = + checkPropertiesForSPIClassName(properties); + if (providerClassName != null) { + return providerClassName; + } + + providerClassName = + checkPropertiesForSPIClassName(System.getProperties()); + if (providerClassName != null) { + return providerClassName; + } + + providerClassName = checkMETAINFServicesForSPIClassName(classLoader); + if (providerClassName == null) { + throw new ServiceRuntimeException( + "Failed to find implementation for SCAClientFactory"); + } + + return providerClassName; + } + + /** + * Attempts to find the class name for the SCAClientFactorySPI + * implementation from the specified Properties. + * + * @return The class name for the SCAClientFactorySPI implementation + * or <code>null</code> if not found. + */ + private static String + checkPropertiesForSPIClassName(Properties properties) { + if (properties == null) { + return null; + } + + final String providerClassName = + properties.getProperty(SCA_CLIENT_FACTORY_PROVIDER_KEY); + if (providerClassName != null && providerClassName.length() > 0) { + return providerClassName; + } + + return null; + } + + /** + * Attempts to find the class name for the SCAClientFactorySPI + * implementation from the META-INF/services directory + * + * @return The class name for the SCAClientFactorySPI implementation or + * <code>null</code> if not found. + */ + private static String checkMETAINFServicesForSPIClassName(ClassLoader cl) + { + final URL url = + cl.getResource(SCA_CLIENT_FACTORY_PROVIDER_META_INF_SERVICE); + if (url == null) { + return null; + } + + InputStream in = null; + try { + in = url.openStream(); + BufferedReader reader = null; + try { + reader = + new BufferedReader(new InputStreamReader(in, "UTF-8")); + + String line; + while ((line = readNextLine(reader)) != null) { + if (!line.startsWith("#") && line.length() > 0) { + return line; + } + } + + return null; + } finally { + closeStream(reader); + } + } catch (IOException ex) { + throw new ServiceRuntimeException( + "Failed to discover SCAClientFactory provider", ex); + } finally { + closeStream(in); + } + } + + /** + * Reads the next line from the reader and returns the trimmed version + * of that line + * + * @param reader The reader from which to read the next line + * @return The trimmed next line or <code>null</code> if the end of the + * stream has been reached + * @throws IOException I/O error occurred while reading from Reader + */ + private static String readNextLine(BufferedReader reader) + throws IOException { + + String line = reader.readLine(); + if (line != null) { + line = line.trim(); + } + return line; + } + + /** + * Loads the specified SCAClientFactory Implementation class. + * + * @param factoryImplClassName The name of the SCAClientFactory + * Implementation class to load + * @return The specified SCAClientFactory Implementation class + * @throws ServiceRuntimeException Failed to load the SCAClientFactory + * Implementation class + */ + private static Class<? extends SCAClientFactory> + loadProviderFactoryClass(String factoryImplClassName, + ClassLoader classLoader) + throws ServiceRuntimeException { + + try { + final Class<?> providerClass = + classLoader.loadClass(factoryImplClassName); + final Class<? extends SCAClientFactory> providerFactoryClass = + providerClass.asSubclass(SCAClientFactory.class); + return providerFactoryClass; + } catch (ClassNotFoundException ex) { + throw new ServiceRuntimeException( + "Failed to load SCAClientFactory implementation class " + + factoryImplClassName, ex); + } catch (ClassCastException ex) { + throw new ServiceRuntimeException( + "Loaded SCAClientFactory implementation class " + + factoryImplClassName + + " is not a subclass of " + + SCAClientFactory.class.getName() , ex); + } + } + + /** + * Instantiate an instance of the specified SCAClientFactorySPI + * Implementation class. + * + * @param factoryImplClass The SCAClientFactorySPI Implementation + * class to instantiate. + * @return An instance of the SCAClientFactorySPI Implementation class + * @throws ServiceRuntimeException Failed to instantiate the specified + * specified SCAClientFactorySPI Implementation class + */ + private static SCAClientFactory instantiateSCAClientFactoryClass( + Class<? extends SCAClientFactory> factoryImplClass, + URI domainURI) + throws NoSuchDomainException, ServiceRuntimeException { + + try { + Constructor<? extends SCAClientFactory> URIConstructor = + factoryImplClass.getConstructor(domainURI.getClass()); + SCAClientFactory provider = + URIConstructor.newInstance( domainURI ); + return provider; + } catch (Throwable ex) { + throw new ServiceRuntimeException( + "Failed to instantiate SCAClientFactory implementation class " + + factoryImplClass, ex); + } + } + + /** + * Utility method for closing Closeable Object. + * + * @param closeable The Object to close. + */ + private static void closeStream(Closeable closeable) { + if (closeable != null) { + try{ + closeable.close(); + } catch (IOException ex) { + throw new ServiceRuntimeException("Failed to close stream", + ex); + } + } + } +} |