TypeProblemMessageBean

/*
 * 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.resource.util;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;

import org.apache.commons.lang.StringUtils;

import de.smartics.exceptions.i18n.message.MessageParam;
import de.smartics.properties.api.core.app.AbstractBaseMessageBean;
import de.smartics.properties.resource.domain.ResourceCode;

/**
 * Provides context information for errors regarding a type.
 */
public final class TypeProblemMessageBean extends AbstractBaseMessageBean
{
  // ********************************* Fields *********************************

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

  /**
   * The class version identifier.
   * <p>
   * The value of this constant is {@value}.
   * </p>
   */
  private static final long serialVersionUID = 1L;

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

  /**
   * The type that is the cause of the problem.
   *
   * @serial
   */
  @MessageParam("type:simpleName,fqn:name")
  private final OgnlInterfaceFix type;

  /**
   * The list of duplicates implementations of the same type.
   *
   * @serial
   */
  private final List<String> duplicates;

  /**
   * The list of errors encountered while trying to instantiate a service type.
   *
   * @serial
   */
  private final List<String> errors;

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

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

  /**
   * Convenience constructor without root cause.
   *
   * @param type the type that is the cause of the problem.
   */
  public TypeProblemMessageBean(final Class<?> type)
  {
    this(null, type);
  }

  /**
   * Default constructor.
   *
   * @param cause the cause to the problem.
   * @param type the type that is the cause of the problem.
   */
  public TypeProblemMessageBean(final Throwable cause, final Class<?> type)
  {
    super(ResourceCode.FACTORY_CANNOT_INSTANTIATE_TYPE, cause);
    this.type = new OgnlInterfaceFix(type);
    this.duplicates = null;
    this.errors = null;
  }

  private TypeProblemMessageBean(final Builder builder)
  {
    super(ResourceCode.SERVICE_FACTORY_PROBLEMS);
    this.type = builder.type;
    this.duplicates = builder.duplicates;
    this.errors = builder.errors;
  }

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

  /**
   * Wrapper around types since the OGNL library fails to get simple names from
   * interfaces.
   */
  private static final class OgnlInterfaceFix implements Serializable
  {
    // ******************************** Fields ********************************

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

    /**
     * The class version identifier.
     * <p>
     * The value of this constant is {@value}.
     * </p>
     */
    private static final long serialVersionUID = 1L;

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

    /**
     * The simple name of the wrapped interface.
     */
    private final String simpleName;

    /**
     * The fqn name of the wrapped interface.
     */
    private final String name;

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

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

    private OgnlInterfaceFix(final Class<?> type)
    {
      this.simpleName = type.getSimpleName();
      this.name = type.getName();
    }

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

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

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

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

    /**
     * Returns the simple name of the wrapped interface.
     *
     * @return the simple name of the wrapped interface.
     */
    @SuppressWarnings("unused")
    public String getSimpleName()
    {
      return simpleName;
    }

    /**
     * Returns the fqn name of the wrapped interface.
     *
     * @return the fqn name of the wrapped interface.
     */
    @SuppressWarnings("unused")
    public String getName()
    {
      return name;
    }

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

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

  /**
   * Creates instances of {@link TypeProblemMessageBean}.
   */
  public static final class Builder
  {
    // ******************************** Fields ********************************

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

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

    /**
     * The type that is the cause of the problem.
     */
    private OgnlInterfaceFix type;

    /**
     * The list of duplicates implementations of the same type.
     */
    private final List<String> duplicates = new ArrayList<String>();

    /**
     * The list of errors encountered while trying to instantiate a service
     * type.
     */
    private final List<String> errors = new ArrayList<String>();

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

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

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

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

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

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

    /**
     * Sets the type that is the cause of the problem.
     *
     * @param type the type that is the cause of the problem.
     * @return a reference to the builder.
     */
    public Builder with(final Class<?> type)
    {
      this.type = new OgnlInterfaceFix(type);
      return this;
    }

    /**
     * Adds the given duplicate implementation to the list.
     *
     * @param duplicate the name of the implementation that implements the given
     *          type.
     * @return a reference to the builder.
     */
    public Builder withDuplicate(final String duplicate)
    {
      duplicates.add(duplicate);
      return this;
    }

    /**
     * Adds the given error message to the list.
     *
     * @param error the error message for detailed information on problems while
     *          instantiating a service type.
     * @return a reference to the builder.
     */
    public Builder withError(final String error)
    {
      errors.add(error);
      return this;
    }

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

    /**
     * Creates the instance.
     *
     * @return the created instance.
     */
    public TypeProblemMessageBean build()
    {
      return new TypeProblemMessageBean(this);
    }

    /**
     * Creates the message.
     *
     * @return the created message.
     */
    public String toMessage()
    {
      return new TypeProblemMessageBean(this).toString();
    }

    /**
     * Checks if duplicates or errors have been reported.
     *
     * @return <code>false</code> if neither duplicates or errors have been
     *         reported, <code>true</code> otherwise.
     */
    public boolean hasReportedProblems()
    {
      return !(duplicates.isEmpty() && errors.isEmpty());
    }

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

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

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

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

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

  /**
   * Returns the list of duplicates implementations of the same type.
   *
   * @return the list of duplicates implementations of the same type as a
   *         message.
   */
  @MessageParam("duplicates")
  public String getDuplicates()
  {
    return toString(duplicates);
  }

  /**
   * Returns the count of duplicates.
   *
   * @return the count of duplicates.
   */
  @MessageParam("duplicateCount")
  public int getDuplicateCount()
  {
    return duplicates != null ? duplicates.size() : 0;
  }

  /**
   * Returns the list of errors encountered while trying to instantiate a
   * service type.
   *
   * @return the list of errors encountered while trying to instantiate a
   *         service type as a message.
   */
  @MessageParam("errors")
  public String getErrors()
  {
    return toString(errors);
  }

  /**
   * Returns the count of errors.
   *
   * @return the count of errors.
   */
  @MessageParam("errorCount")
  public int getErrorCount()
  {
    return errors != null ? errors.size() : 0;
  }

  private static String toString(final List<String> items)
  {
    if (items == null)
    {
      return null;
    }

    final StringBuilder buffer = new StringBuilder(64);
    for (final String item : items)
    {
      buffer.append("  ").append(item).append('\n');
    }
    return StringUtils.chomp(buffer.toString());
  }

  @Override
  public String toString()
  {
    return this.getCode().getDisplayId() + ": " + this.getMessages();
  }

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

}