de.fuberlin.wiwiss.r2r.LoadingFunctionManager.java Source code

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Here is the source code for de.fuberlin.wiwiss.r2r.LoadingFunctionManager.java

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/*
 *  R2R
 *
 *  Copyright 2010-2011 Freie Universitt Berlin
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  Modified by ?caro Medeiros 2012
 */
package de.fuberlin.wiwiss.r2r;

import java.net.MalformedURLException;
import java.util.HashMap;
import java.util.Map;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * a FunctionManager that tries to load Functions from the class path or from a URL.
 * The load informations are taken from a Source repository.
 * @author andreas
 *
 */
public class LoadingFunctionManager implements FunctionManager {
    private static Log log = LogFactory.getLog(LoadingFunctionManager.class);
    private Map<String, FunctionFactory> functions = new HashMap<String, FunctionFactory>();
    private FunctionFactoryLoader ffLoader;
    private static FunctionManager basicFunctions = new BasicFunctionManager();

    public LoadingFunctionManager(Source functionInfoRepository) {
        ffLoader = new FunctionFactoryLoader(functionInfoRepository);
    }

    public synchronized boolean containsFunctionByUri(String URI) {
        return functions.containsKey(URI) || basicFunctions.containsFunctionByUri(URI);
    }

    public Function getFunctionByUri(String URI) {
        if (basicFunctions.containsFunctionByUri(URI))
            return basicFunctions.getFunctionByUri(URI);

        // Try to load function if not present in this manager
        if (!functions.containsKey(URI)) {
            if (ffLoader == null)
                throw new IllegalArgumentException("No function found with URI/ID: " + URI);
            else {
                try {
                    FunctionFactory ff = ffLoader.getFunctionFactory(URI);
                    if (ff != null) {
                        synchronized (functions) {
                            functions.put(URI, ff);
                        }
                    } else
                        return null;// Could not load Function
                } catch (MalformedURLException e) {
                    if (log.isDebugEnabled())
                        log.debug("TransformationFunction <" + URI + "> could not be loaded: " + e.toString());
                    if (Config.rethrowActivated())
                        throw new R2RException(
                                "TransformationFunction <" + URI + "> could not be loaded: " + e.toString(), e);
                    return null;
                }
            }
        }
        FunctionFactory factory = functions.get(URI);
        if (factory instanceof MultiFunctionFactory) {
            return ((MultiFunctionFactory) factory).getInstance(URI);
        }
        return functions.get(URI).getInstance();
    }

    public synchronized boolean registerFunctionFactory(String uri, FunctionFactory functionFactory) {
        synchronized (functions) {
            if (functions.containsKey(uri))
                return false;
            functions.put(uri, functionFactory);
        }
        return true;
    }

}