Package org.apache.tuscany.sca.contribution.processor

Source Code of org.apache.tuscany.sca.contribution.processor.DefaultStAXArtifactProcessorExtensionPoint$LazyStAXArtifactProcessor

/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements.  See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership.  The ASF licenses this file
* to you 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 org.apache.tuscany.sca.contribution.processor;

import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.Map;
import java.util.Set;

import javax.xml.namespace.QName;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLOutputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;

import org.apache.tuscany.sca.assembly.AssemblyFactory;
import org.apache.tuscany.sca.assembly.builder.impl.ProblemImpl;
import org.apache.tuscany.sca.contribution.ModelFactoryExtensionPoint;
import org.apache.tuscany.sca.contribution.resolver.ModelResolver;
import org.apache.tuscany.sca.contribution.service.ContributionReadException;
import org.apache.tuscany.sca.contribution.service.ContributionResolveException;
import org.apache.tuscany.sca.contribution.service.ContributionWriteException;
import org.apache.tuscany.sca.core.ExtensionPointRegistry;
import org.apache.tuscany.sca.core.UtilityExtensionPoint;
import org.apache.tuscany.sca.extensibility.ServiceDeclaration;
import org.apache.tuscany.sca.extensibility.ServiceDiscovery;
import org.apache.tuscany.sca.policy.PolicyFactory;
import org.apache.tuscany.sca.monitor.Monitor;
import org.apache.tuscany.sca.monitor.MonitorFactory;
import org.apache.tuscany.sca.monitor.Problem;
import org.apache.tuscany.sca.monitor.Problem.Severity;

/**
* The default implementation of an extension point for StAX artifact processors.
*
* @version $Rev: 667376 $ $Date: 2008-06-13 07:29:16 +0100 (Fri, 13 Jun 2008) $
*/
public class DefaultStAXArtifactProcessorExtensionPoint extends
    DefaultArtifactProcessorExtensionPoint<StAXArtifactProcessor> implements StAXArtifactProcessorExtensionPoint {

    private ExtensionPointRegistry extensionPoints;
    private ModelFactoryExtensionPoint modelFactories;
    private MonitorFactory monitorFactory;
    private boolean loaded;
    private StAXArtifactProcessor<Object> extensibleStAXProcessor;
    private Monitor monitor = null;

    /**
     * Constructs a new extension point.
     */
    public DefaultStAXArtifactProcessorExtensionPoint(ExtensionPointRegistry extensionPoints) {
        this.extensionPoints = extensionPoints;
        this.modelFactories = extensionPoints.getExtensionPoint(ModelFactoryExtensionPoint.class);
        XMLInputFactory inputFactory = modelFactories.getFactory(XMLInputFactory.class);
        XMLOutputFactory outputFactory = modelFactories.getFactory(XMLOutputFactory.class);
        UtilityExtensionPoint utilities = this.extensionPoints.getExtensionPoint(UtilityExtensionPoint.class);
        MonitorFactory monitorFactory = utilities.getUtility(MonitorFactory.class);
        if (monitorFactory != null)
          this.monitor = monitorFactory.createMonitor();
        this.extensibleStAXProcessor = new ExtensibleStAXArtifactProcessor(this, inputFactory, outputFactory, this.monitor);
    }
   
    /**
     * Report a exception.
     *
     * @param problems
     * @param message
     * @param model
    */
    private void error(String message, Object model, Exception ex) {
        if (monitor != null) {
          Problem problem = new ProblemImpl(this.getClass().getName(), "contribution-validation-messages", Severity.ERROR, model, message, ex);
          monitor.problem(problem);
      }       
    }

    public void addArtifactProcessor(StAXArtifactProcessor artifactProcessor) {
        if (artifactProcessor.getArtifactType() != null) {
            processorsByArtifactType.put((Object)artifactProcessor.getArtifactType(), artifactProcessor);
        }
        if (artifactProcessor.getModelType() != null) {
            processorsByModelType.put(artifactProcessor.getModelType(), artifactProcessor);
        }
    }

    public void removeArtifactProcessor(StAXArtifactProcessor artifactProcessor) {
        if (artifactProcessor.getArtifactType() != null) {
            processorsByArtifactType.remove((Object)artifactProcessor.getArtifactType());
        }
        if (artifactProcessor.getModelType() != null) {
            processorsByModelType.remove(artifactProcessor.getModelType());
        }
    }

    @Override
    public StAXArtifactProcessor getProcessor(Class<?> modelType) {
        loadArtifactProcessors();
        return super.getProcessor(modelType);
    }

    @Override
    public StAXArtifactProcessor getProcessor(Object artifactType) {
        loadArtifactProcessors();
        return super.getProcessor(artifactType);
    }

    /**
     * Returns a QName object from a QName expressed as {ns}name
     * or ns#name.
     *
     * @param qname
     * @return
     */
    private static QName getQName(String qname) {
        if (qname == null) {
            return null;
        }
        qname = qname.trim();
        if (qname.startsWith("{")) {
            int h = qname.indexOf('}');
            if (h != -1) {
                return new QName(qname.substring(1, h), qname.substring(h + 1));
            }
        } else {
            int h = qname.indexOf('#');
            if (h != -1) {
                return new QName(qname.substring(0, h), qname.substring(h + 1));
            }
        }
        throw new IllegalArgumentException("Invalid qname: "+qname);
    }

    /**
     * Lazily load artifact processors registered in the extension point.
     */
    private void loadArtifactProcessors() {
        if (loaded)
            return;

        // Get the processor service declarations
        Set<ServiceDeclaration> processorDeclarations;
        try {
            processorDeclarations = ServiceDiscovery.getInstance().getServiceDeclarations(StAXArtifactProcessor.class);
        } catch (IOException e) {
          IllegalStateException ie = new IllegalStateException(e);
          error("IllegalStateException", extensibleStAXProcessor, ie);
            throw ie;
        }

        for (ServiceDeclaration processorDeclaration : processorDeclarations) {
            Map<String, String> attributes = processorDeclaration.getAttributes();

            // Load a StAX artifact processor

            // Get the model QName
            QName artifactType = getQName(attributes.get("qname"));

            // Get the model class name
            String modelTypeName = attributes.get("model");

            // Get the model factory class name
            String factoryName = attributes.get("factory");

            // Create a processor wrapper and register it
            StAXArtifactProcessor processor =
                new LazyStAXArtifactProcessor(artifactType, modelTypeName, factoryName,
                                              processorDeclaration, extensionPoints, modelFactories,
                                              extensibleStAXProcessor, monitor);
            addArtifactProcessor(processor);
        }

        loaded = true;
    }

    /**
     * A wrapper around an Artifact processor class allowing lazy loading and
     * initialization of artifact processors.
     */
    private static class LazyStAXArtifactProcessor implements StAXArtifactProcessor {

        private ExtensionPointRegistry extensionPoints;
        private QName artifactType;
        private String modelTypeName;
        private String factoryName;
        private ServiceDeclaration processorDeclaration;
        private StAXArtifactProcessor processor;
        private Class<?> modelType;
        private StAXArtifactProcessor<Object> extensionProcessor;
        private Monitor monitor;

        LazyStAXArtifactProcessor(QName artifactType,
                                  String modelTypeName,
                                  String factoryName,
                                  ServiceDeclaration processorDeclaration,
                                  ExtensionPointRegistry extensionPoints,
                                  ModelFactoryExtensionPoint modelFactories,
                                  StAXArtifactProcessor<Object> extensionProcessor,
                                  Monitor monitor) {

            this.extensionPoints = extensionPoints;
            this.artifactType = artifactType;
            this.modelTypeName = modelTypeName;
            this.factoryName = factoryName;
            this.processorDeclaration = processorDeclaration;
            this.extensionProcessor = extensionProcessor;
            this.monitor = monitor;
        }

        public QName getArtifactType() {
            return artifactType;
        }
       
        private void error(String message, Object model, Exception ex) {
            if (monitor != null) {
              Problem problem = new ProblemImpl(this.getClass().getName(), "contribution-validation-messages", Severity.ERROR, model, message, ex);
              monitor.problem(problem);
          }       
        }

        @SuppressWarnings("unchecked")
        private StAXArtifactProcessor getProcessor() {
            if (processor == null) {

                if (processorDeclaration.getClassName()
                    .equals("org.apache.tuscany.sca.assembly.xml.DefaultBeanModelProcessor")) {

                    // Specific initialization for the DefaultBeanModelProcessor
                    ModelFactoryExtensionPoint modelFactories = extensionPoints.getExtensionPoint(ModelFactoryExtensionPoint.class);
                    AssemblyFactory assemblyFactory = modelFactories.getFactory(AssemblyFactory.class);
                    PolicyFactory policyFactory = modelFactories.getFactory(PolicyFactory.class);
                    try {
                        Class<StAXArtifactProcessor> processorClass =
                            (Class<StAXArtifactProcessor>)processorDeclaration.loadClass();
                        Object modelFactory;
                        if (factoryName != null) {
                            Class<?> factoryClass = (Class<?>)processorDeclaration.loadClass(factoryName);
                            modelFactory = modelFactories.getFactory(factoryClass);
                        } else {
                            modelFactory = null;
                        }
                        Constructor<StAXArtifactProcessor> constructor =
                            processorClass.getConstructor(AssemblyFactory.class,
                                                          PolicyFactory.class,
                                                          QName.class,
                                                          Class.class,
                                                          Object.class,
                                                          Monitor.class);
                        processor =
                            constructor.newInstance(assemblyFactory,
                                                    policyFactory,
                                                    artifactType,
                                                    getModelType(),
                                                    modelFactory,
                                                    monitor);
                    } catch (Exception e) {
                      IllegalStateException ie = new IllegalStateException(e);
                      error("IllegalStateException", processor, ie);
                        throw ie;
                    }
                } else {
                    ModelFactoryExtensionPoint modelFactories = extensionPoints.getExtensionPoint(ModelFactoryExtensionPoint.class);

                    // Load and instantiate the processor class
                    try {
                        Class<StAXArtifactProcessor> processorClass =
                            (Class<StAXArtifactProcessor>)processorDeclaration.loadClass();
                        try {
                            Constructor<StAXArtifactProcessor> constructor =
                                processorClass.getConstructor(ModelFactoryExtensionPoint.class, Monitor.class);
                            processor = constructor.newInstance(modelFactories, monitor);
                        } catch (NoSuchMethodException e) {
                          try {
                              Constructor<StAXArtifactProcessor> constructor =
                                  processorClass.getConstructor(ExtensionPointRegistry.class, Monitor.class);
                              processor = constructor.newInstance(extensionPoints, monitor);
                          } catch (NoSuchMethodException e1) {
                            try {
                                Constructor<StAXArtifactProcessor> constructor =
                                    processorClass.getConstructor(ModelFactoryExtensionPoint.class, StAXArtifactProcessor.class, Monitor.class);
                                processor = constructor.newInstance(modelFactories, extensionProcessor, monitor);
                            } catch (NoSuchMethodException e2) {
                                try {
                                    Constructor<StAXArtifactProcessor> constructor =
                                        processorClass.getConstructor(ExtensionPointRegistry.class, StAXArtifactProcessor.class, Monitor.class);
                                    processor = constructor.newInstance(extensionPoints, extensionProcessor, monitor);
                                } catch (NoSuchMethodException e3) {
                                    try {
                                        Constructor<StAXArtifactProcessor> constructor =
                                            processorClass.getConstructor(ModelFactoryExtensionPoint.class);
                                        processor = constructor.newInstance(modelFactories);
                                    } catch (NoSuchMethodException e4) {
                                      try {
                                          Constructor<StAXArtifactProcessor> constructor =
                                              processorClass.getConstructor(ExtensionPointRegistry.class);
                                          processor = constructor.newInstance(extensionPoints);
                                      } catch (NoSuchMethodException e4a) {
                                        try {
                                            Constructor<StAXArtifactProcessor> constructor =
                                                processorClass.getConstructor(ModelFactoryExtensionPoint.class, StAXArtifactProcessor.class);
                                            processor = constructor.newInstance(modelFactories, extensionProcessor);
                                        } catch (NoSuchMethodException e5) {
                                            Constructor<StAXArtifactProcessor> constructor =
                                                processorClass.getConstructor(ExtensionPointRegistry.class, StAXArtifactProcessor.class);
                                            processor = constructor.newInstance(extensionPoints, extensionProcessor);
                                        }
                                      }
                                    }
                                }
                            }
                          }
                        }
                    } catch (Exception e) {
                      IllegalStateException ie = new IllegalStateException(e);
                      error("IllegalStateException", processor, ie);
                        throw ie;
                    }
                }
            }
            return processor;
        }

        public Object read(XMLStreamReader inputSource) throws ContributionReadException, XMLStreamException {
            return getProcessor().read(inputSource);
        }

        @SuppressWarnings("unchecked")
        public void write(Object model, XMLStreamWriter outputSource) throws ContributionWriteException,
            XMLStreamException {
            getProcessor().write(model, outputSource);
        }

        public Class<?> getModelType() {
            if (modelTypeName != null && modelType == null) {
                try {
                    modelType = processorDeclaration.loadClass(modelTypeName);
                } catch (Exception e) {
                  IllegalStateException ie = new IllegalStateException(e);
                  error("IllegalStateException", processorDeclaration, ie);
                    throw ie;
                }
            }
            return modelType;
        }

        @SuppressWarnings("unchecked")
        public void resolve(Object model, ModelResolver resolver) throws ContributionResolveException {
            getProcessor().resolve(model, resolver);
        }

    }
}
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