com.b2international.snowowl.datastore.ClientProtocolFactoryRegistry.java Source code

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Here is the source code for com.b2international.snowowl.datastore.ClientProtocolFactoryRegistry.java

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/*
 * Copyright 2011-2015 B2i Healthcare Pte Ltd, http://b2i.sg
 * 
 * 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.
 */
package com.b2international.snowowl.datastore;

import java.util.Arrays;
import java.util.List;

import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IConfigurationElement;
import org.eclipse.core.runtime.Platform;
import org.eclipse.spi.net4j.ClientProtocolFactory;

import com.b2international.snowowl.core.CoreTerminologyBroker;
import com.google.common.base.Function;
import com.google.common.collect.Lists;

/**
 * Registry for custom Net4j client protocol factories.
 * 
 * @see org.eclipse.spi.net4j.ClientProtocolFactory
 */
public class ClientProtocolFactoryRegistry {

    private static final String EXTENSION_POINT_ID = "com.b2international.snowowl.datastore.protocolFactory";
    private static final String CLASS_ATTRIBUTE = "class";
    private static ClientProtocolFactoryRegistry instance;

    public List<ClientProtocolFactory> getRegisteredClientProtocolFactories() {
        IConfigurationElement[] configurationElements = Platform.getExtensionRegistry()
                .getConfigurationElementsFor(EXTENSION_POINT_ID);
        return Lists.transform(Arrays.asList(configurationElements),
                new Function<IConfigurationElement, ClientProtocolFactory>() {
                    @Override
                    public ClientProtocolFactory apply(IConfigurationElement input) {
                        try {
                            return (ClientProtocolFactory) input.createExecutableExtension(CLASS_ATTRIBUTE);
                        } catch (final CoreException e) {
                            throw new RuntimeException(
                                    "Error while creating executable extension from the passed in configuration element: "
                                            + input,
                                    e);
                        }
                    }
                });
    }

    private ClientProtocolFactoryRegistry() {
    }

    public static ClientProtocolFactoryRegistry getInstance() {
        if (instance == null) {
            synchronized (CoreTerminologyBroker.class) {
                if (instance == null)
                    instance = new ClientProtocolFactoryRegistry();
            }
        }
        return instance;
    }
}