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 *  or more contributor license agreements.  See the NOTICE file
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 *  to you under the Apache License, Version 2.0 (the
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package org.apache.cayenne.project.extension;

import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.cayenne.CayenneRuntimeException;
import org.apache.cayenne.configuration.xml.DefaultHandlerFactory;
import org.apache.cayenne.configuration.xml.NamespaceAwareNestedTagHandler;
import org.apache.cayenne.di.Inject;

/**
 * Project parser handlers factory that will use third-party extensions
 * to provide handlers for unknown tags.
 *
 * @see ProjectExtension
 * @see DefaultHandlerFactory
 *
 * @since 4.1
 */
public class ExtensionAwareHandlerFactory extends DefaultHandlerFactory {

    Map loaderDelegates = new ConcurrentHashMap<>();

    public ExtensionAwareHandlerFactory(@Inject List extensions) {
        for(ProjectExtension extension : extensions) {
            LoaderDelegate delegate = extension.createLoaderDelegate();
            LoaderDelegate old = loaderDelegates.put(delegate.getTargetNamespace(), delegate);
            if(old != null) {
                throw new CayenneRuntimeException("Found two loader delegates for namespace %s",
                        delegate.getTargetNamespace());
            }
        }
    }

    @Override
    public NamespaceAwareNestedTagHandler createHandler(String namespace, String localName,
                                                        NamespaceAwareNestedTagHandler parent) {

        LoaderDelegate delegate = loaderDelegates.get(namespace);
        if(delegate != null) {
            NamespaceAwareNestedTagHandler handler = delegate.createHandler(parent, localName);
            if(handler != null) {
                return handler;
            }
        }

        return super.createHandler(namespace, localName, parent);
    }
}