/*
* ====================
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 2008-2009 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of the Common Development
* and Distribution License("CDDL") (the "License"). You may not use this file
* except in compliance with the License.
*
* You can obtain a copy of the License at
* http://opensource.org/licenses/cddl1.php
* See the License for the specific language governing permissions and limitations
* under the License.
*
* When distributing the Covered Code, include this CDDL Header Notice in each file
* and include the License file at http://opensource.org/licenses/cddl1.php.
* If applicable, add the following below this CDDL Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
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* ====================
*/
package org.identityconnectors.common.script;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Enumeration;
import java.util.List;
import java.util.Map;
import java.util.Set;
import org.identityconnectors.common.CollectionUtil;
import org.identityconnectors.common.StringUtil;
import org.identityconnectors.framework.api.operations.ScriptOnConnectorApiOp;
import org.identityconnectors.framework.spi.operations.ScriptOnConnectorOp;
import org.identityconnectors.framework.spi.operations.ScriptOnResourceOp;
/**
* Abstraction for finding script executors to allow us to invoke scripts from
* java.
* <p>
* <b>NOTE: </b> This is intended purely for executing java-embedable scripting
* languages. That is, the execution model is assumed to be same-JVM, so scripts
* can have side effects on objects passed to the script. This is used
* internally by the connector framework in its implementation of
* {@link ScriptOnConnectorApiOp} and should be used by connectors should they
* need to have a custom implementation of {@link ScriptOnConnectorOp}. This is
* <b>not</b> intended for use by connectors that implement
* {@link ScriptOnResourceOp}.
*/
public abstract class ScriptExecutorFactory {
private static Map<String, Class<?>> factoryCache;
private static synchronized Map<String, Class<?>> getFactoryCache() {
if (factoryCache == null) {
factoryCache = CollectionUtil.newCaseInsensitiveMap();
List<String> factories = getRegisteredFactories();
for (String factory : factories) {
try {
Class<?> clazz = Class.forName(factory);
// Create an instance in order to get the supported
// language.
ScriptExecutorFactory instance = (ScriptExecutorFactory) clazz.newInstance();
String language = instance.getLanguageName();
// Do not override a factory earlier in the classpath.
if (!factoryCache.containsKey(language)) {
factoryCache.put(language, clazz);
}
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
// Probably an error loading or instantiating the SEF
// implementation.
// Do not report.
}
}
}
return factoryCache;
}
/**
* Returns the factories registered through META-INF/services.
*
* @return a non-null list of factory class names.
*/
private static List<String> getRegisteredFactories() {
// Would be nice to move this method to IOUtil when external
// registrations for another SPI
// are supported. Currently it would have two clients
// (ScriptExecutorFactory and Log).
// Better to have three before it is turned into an API.
List<String> result = new ArrayList<String>();
String path = "META-INF/services/" + ScriptExecutorFactory.class.getName();
try {
Enumeration<URL> configFiles =
ScriptExecutorFactory.class.getClassLoader().getResources(path);
while (configFiles.hasMoreElements()) {
URL configFile = configFiles.nextElement();
addFactories(configFile, result);
}
return result;
} catch (IOException e) {
throw new RuntimeException(e);
}
}
private static void addFactories(URL configFile, List<String> result) throws IOException {
InputStream input = configFile.openStream();
try {
// Encoding as per JAR file spec.
BufferedReader reader = new BufferedReader(new InputStreamReader(input, "UTF-8"));
try {
String line = reader.readLine();
while (line != null) {
int comment = line.indexOf('#');
if (comment >= 0) {
line = line.substring(0, comment);
}
line = line.trim();
if (StringUtil.isNotBlank(line)) {
result.add(line);
}
line = reader.readLine();
}
} finally {
reader.close();
}
} finally {
input.close();
}
}
/**
* Returns the set of supported languages.
*
* @return The set of supported languages.
*/
public static Set<String> getSupportedLanguages() {
return Collections.unmodifiableSet(getFactoryCache().keySet());
}
/**
* Creates a ScriptExecutorFactory for the given language.
*
* @param language
* The name of the language
* @return The script executor factory
* @throws IllegalArgumentException
* If the given language is not supported.
*/
public static ScriptExecutorFactory newInstance(String language) {
if (StringUtil.isBlank(language)) {
throw new IllegalArgumentException("Language must be specified");
}
Class<?> clazz = getFactoryCache().get(language);
if (clazz == null) {
throw new IllegalArgumentException(String
.format("Language not supported: %s", language));
}
// exceptions here should not happened because of the register
try {
return (ScriptExecutorFactory) clazz.newInstance();
} catch (RuntimeException e) {
throw e;
} catch (Exception e) {
// should never happen
throw new RuntimeException(e);
}
}
/**
* Creates a script executor for the given script.
*
* @param loader
* The classloader that contains the java classes that the script
* should have access to.
* @param script
* The script text.
* @param compile
* A hint to tell the script executor whether or not to compile
* the given script. This need not be implemented by all script
* executors. If true, the caller is saying that they intend to
* call the script multiple times with different arguments, so
* compile if possible.
* @return A script executor.
*/
public abstract ScriptExecutor newScriptExecutor(ClassLoader loader, String script,
boolean compile);
/**
* Returns the name of the language supported by this factory.
*
* @return the name of the language.
*/
public abstract String getLanguageName();
}