MetaInfDocumentMetaDataProxy

/*
 * Copyright 2012-2013 smartics, Kronseder & Reiner GmbH
 *
 * 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 de.smartics.properties.spi.core.metadata;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;

import javax.annotation.concurrent.ThreadSafe;

import org.apache.commons.lang.StringUtils;
import org.apache.commons.lang.builder.ToStringBuilder;

import de.smartics.projectdoc.annotations.Document;
import de.smartics.properties.api.core.domain.DocumentName;
import de.smartics.properties.api.core.domain.PropertiesContext;
import de.smartics.properties.api.core.domain.PropertyDescriptor;
import de.smartics.properties.api.core.domain.PropertyKey;
import de.smartics.properties.api.core.domain.PropertyProjectdoc;
import de.smartics.properties.api.core.domain.PropertySetProjectdoc;
import de.smartics.properties.spi.core.metadata.projectdoc.AnnotationHelper;
import de.smartics.properties.spi.core.metadata.projectdoc.ProjectdocAnnotationCollector;
import de.smartics.properties.spi.core.metadata.projectdoc.ProjectdocAnnotationCollector.Defaults;
import de.smartics.properties.spi.core.metadata.projectdoc.PropertyProjectdocParser;
import de.smartics.properties.spi.core.metadata.projectdoc.PropertySetProjectdocParser;
import de.smartics.properties.spi.core.util.SerializableMethod;
import de.smartics.util.lang.Arg;

/**
 * Allows to lazy load annotation information.
 */
@ThreadSafe
public final class MetaInfDocumentMetaDataProxy implements
    DocumentMetaDataProxy
{
  // ********************************* Fields *********************************

  // --- constants ------------------------------------------------------------

  /**
   * The class version identifier.
   */
  private static final long serialVersionUID = 1L;

  // --- members --------------------------------------------------------------

  /**
   * The name of the document that identifies the document uniquely within the
   * context of the project. It is used to select the projectdoc document in the
   * <code>META-INF</code> folder.
   *
   * @serial
   */
  private final DocumentName documentName;

  /**
   * The properties context to fetch information from the <code>META-INF</code>
   * folder. May be <code>null</code>.
   *
   * @serial
   */
  private final PropertiesContext context;

  /**
   * The method to use to fetch annotations in case the context is not to be
   * used.
   *
   * @serial
   */
  private final SerializableMethod propertyMethod;

  /**
   * The cached property comments.
   *
   * @serial
   */
  private final Map<Locale, PropertyProjectdoc> metaData =
      new HashMap<Locale, PropertyProjectdoc>();

  /**
   * The cached property set comments.
   *
   * @serial
   */
  private final Map<Locale, PropertySetProjectdoc> propertySetMetaData =
      new HashMap<Locale, PropertySetProjectdoc>();

  // ****************************** Initializer *******************************

  // ****************************** Constructors ******************************

  /**
   * Default constructor.
   *
   * @param key the property key to the method.
   * @param context the properties context to fetch information from the
   *          <code>META-INF</code> folder. May be <code>null</code>.
   * @param propertyMethod the method to use to fetch annotations in case the
   *          context is not to be used.
   * @throws NullPointerException if {@code key} or {@code propertyMethod} is
   *           {@code null}.
   */
  public MetaInfDocumentMetaDataProxy(final PropertyKey key,
      final PropertiesContext context, final Method propertyMethod)
    throws NullPointerException
  {
    Arg.checkNotNull("key", key);

    this.context = context;
    this.propertyMethod =
        new SerializableMethod(Arg.checkNotNull("propertyMethod",
            propertyMethod));
    this.documentName = calculateDocumentName(key, propertyMethod);
  }

  // ****************************** Inner Classes *****************************

  // ********************************* Methods ********************************

  // --- init -----------------------------------------------------------------

  // --- get&set --------------------------------------------------------------

  private static DocumentName calculateDocumentName(final PropertyKey key,
      final Method propertyMethod)
  {
    final Document annotation = propertyMethod.getAnnotation(Document.class);
    String name = propertyMethod.getName();
    if (annotation != null)
    {
      final String value = annotation.name();
      if (value != null)
      {
        final AnnotationHelper helper = new AnnotationHelper();
        final String annName = helper.normalizeString(value);
        if (StringUtils.isNotBlank(annName)) // NOPMD
        {
          name = annName;
        }
      }
    }

    final String setName = key.getPropertySet();
    final String fqn = setName != null ? setName + '.' + name : name;
    final DocumentName documentName = new DocumentName(fqn);
    return documentName;
  }

  /**
   * Returns the name of the document that identifies the document uniquely
   * within the context of the project. It is used to select the projectdoc
   * document in the <code>META-INF</code> folder.
   *
   * @return the name of the document that identifies the document uniquely
   *         within the context of the project.
   */
  @Override
  public DocumentName getDocumentName()
  {
    return documentName;
  }

  // --- business -------------------------------------------------------------

  @Override
  public PropertySetProjectdoc getProjectdocPropertySet(
      final PropertyDescriptor descriptor, final Locale locale)
  {
    synchronized (propertySetMetaData)
    {
      PropertySetProjectdoc metaData = propertySetMetaData.get(locale);

      if (metaData == null)
      {
        final Method propertyMethod = this.propertyMethod.getMethod();

        ensureMethodPresent(propertyMethod);

        if (context != null)
        {
          final Defaults defaults =
              PropertyMetaDataDefaults.propertySet(propertyMethod);
          final PropertySetProjectdocParser parser =
              new PropertySetProjectdocParser(context, defaults);
          metaData = parser.parse(descriptor, locale);
        }

        if (metaData == null)
        {
          metaData = new PropertySetProjectdoc();
        }

        this.propertySetMetaData.put(locale, metaData);
      }

      return metaData;
    }
  }

  @Override
  public PropertyProjectdoc getProjectdocProperty(
      final PropertyDescriptor descriptor, final Locale locale)
  {
    synchronized (metaData)
    {
      PropertyProjectdoc metaData = this.metaData.get(locale);

      if (metaData == null)
      {
        final Method propertyMethod = this.propertyMethod.getMethod();

        ensureMethodPresent(propertyMethod);

        if (context != null)
        {
          final Defaults defaults =
              new PropertyMetaDataDefaults(propertyMethod);
          final PropertyProjectdocParser parser =
              new PropertyProjectdocParser(context, defaults);
          metaData = parser.parse(descriptor, locale);
        }

        if (metaData == null)
        {
          final Class<?> declaringType = propertyMethod.getDeclaringClass();
          final Defaults parentDefaults =
              new PropertyMetaDataDefaults(declaringType, propertyMethod);
          final Defaults defaults =
              new PropertyMetaDataDefaults(propertyMethod);
          final ProjectdocAnnotationCollector collector =
              new ProjectdocAnnotationCollector(declaringType, parentDefaults,
                  defaults);

          metaData =
              PropertyProjectdoc.upgrade(collector
                  .createMetaDataFromAnnotations(propertyMethod));
        }

        if (metaData != null)
        {
          this.metaData.put(locale, metaData);
        }
      }

      return metaData;
    }
  }

  private void ensureMethodPresent(final Method propertyMethod)
  {
    if (propertyMethod == null)
    {
      throw new IllegalStateException(
          "Cannot find documentation for method value 'null'.");
    }
  }

  // --- object basics --------------------------------------------------------

  /**
   * Returns the string representation of the object.
   *
   * @return the string representation of the object.
   */
  @Override
  public String toString()
  {
    return ToStringBuilder.reflectionToString(this);
  }
}