PropertiesDefinitionContext

/*
 * 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.config.definition;

import java.io.Serializable;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

import javax.annotation.CheckForNull;
import javax.annotation.concurrent.ThreadSafe;

import de.smartics.properties.api.config.domain.key.ConfigurationKey;

/**
 * Contains information from the <code>definition.xml</code> that is contained
 * in archives providing property information.
 */
@ThreadSafe
public final class PropertiesDefinitionContext implements Serializable
{
  // ********************************* Fields *********************************

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

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

  /**
   * The default top level domains to identify groups.
   * <ol>
   * <li><code>biz</code></li>
   * <li><code>com</code></li>
   * <li><code>edu</code></li>
   * <li><code>gov</code></li>
   * <li><code>info</code></li>
   * <li><code>net</code></li>
   * <li><code>org</code></li>
   * </ol>
   */
  public static final Set<String> DEFAULT_TLDS;

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

  /**
   * The collection of top-level-domains (tlds). Country codes (two letters) are
   * not necessarily mentioned here since they are dealt with generically.
   *
   * @serial
   */
  private final Set<String> tlds;

  /**
   * The collection of registered environment names.
   *
   * @serial
   */
  private final Set<String> environments;

  /**
   * The collection of registered node names.
   *
   * @serial
   */
  private final Set<String> nodes;

  /**
   * The collection of registered group names.
   *
   * @serial
   */
  private final Set<String> groups;

  /**
   * The mapping of properties file path names to a associated configuration
   * key.
   *
   * @serial
   */
  private final Map<String, ConfigurationKey> files;

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

  static
  {
    final Set<String> defaults = new HashSet<String>();
    defaults.add("biz");
    defaults.add("com");
    defaults.add("edu");
    defaults.add("gov");
    defaults.add("info");
    defaults.add("net");
    defaults.add("org");
    DEFAULT_TLDS = Collections.unmodifiableSet(defaults);
  }

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

  /**
   * Convenience constructor using the default TLDs and not registering any
   * environments, nodes or groups.
   */
  public PropertiesDefinitionContext()
  {
    this(DEFAULT_TLDS, null, null, null, null);
  }

  /**
   * Convenience constructor using the default TLDs and no explicit files.
   *
   * @param environments the collection of registered environment names.
   * @param nodes the collection of registered node names.
   * @param groups the collection of registered group names.
   */
  public PropertiesDefinitionContext(final Set<String> environments,
      final Set<String> nodes, final Set<String> groups)
  {
    this(DEFAULT_TLDS, environments, nodes, groups);
  }

  /**
   * Convenience constructor without an explicit path to configuration key
   * mapping.
   *
   * @param tlds the collection of top-level-domains (tlds).
   * @param environments the collection of registered environment names.
   * @param nodes the collection of registered node names.
   * @param groups the collection of registered group names.
   */
  public PropertiesDefinitionContext(final Set<String> tlds,
      final Set<String> environments, final Set<String> nodes,
      final Set<String> groups)
  {
    this(tlds, environments, nodes, groups, null);
  }

  /**
   * Convenience constructor using the default TLDs.
   *
   * @param environments the collection of registered environment names.
   * @param nodes the collection of registered node names.
   * @param groups the collection of registered group names.
   * @param files the mapping of properties file path names to a associated
   *          configuration key.
   */
  public PropertiesDefinitionContext(final Set<String> environments,
      final Set<String> nodes, final Set<String> groups,
      final Map<String, ConfigurationKey> files)
  {
    this(DEFAULT_TLDS, environments, nodes, groups, files);
  }

  /**
   * Default constructor.
   *
   * @param tlds the collection of top-level-domains (tlds).
   * @param environments the collection of registered environment names.
   * @param nodes the collection of registered node names.
   * @param groups the collection of registered group names.
   * @param files the mapping of properties file path names to a associated
   *          configuration key.
   */
  public PropertiesDefinitionContext(final Set<String> tlds,
      final Set<String> environments, final Set<String> nodes,
      final Set<String> groups, final Map<String, ConfigurationKey> files)
  {
    this.tlds = create(tlds);
    this.environments = create(environments);
    this.nodes = create(nodes);
    this.groups = create(groups);
    this.files = create(files);
  }

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

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

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

  private static Set<String> create(final Set<String> set)
  {
    return set != null ? new HashSet<String>(set) : new HashSet<String>();
  }

  private static Map<String, ConfigurationKey> create(
      final Map<String, ConfigurationKey> map)
  {
    return map != null ? new HashMap<String, ConfigurationKey>(map)
        : new HashMap<String, ConfigurationKey>();
  }

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

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

  /**
   * Checks if the given string is a registered top level domain (tld) or
   * contains only two letters.
   *
   * @param token the token to check.
   * @return <code>true</code> if the {@code token} is not <code>null</code>, is
   *         registered or contains exactly two letters, <code>false</code>
   *         otherwise.
   */
  public boolean isRegisteredGroupTld(final String token)
  {
    return token != null && (tlds.contains(token) || isCountryTld(token));
  }

  private static boolean isCountryTld(final String tld)
  {
    return tld.length() == 2 && Character.isLetter(tld.charAt(0))
           && Character.isLetter(tld.charAt(1));
  }

  /**
   * Checks if the given token is a registered environment.
   *
   * @param token the token to check.
   * @return <code>true</code> if the token is a registered environment,
   *         <code>false</code> otherwise.
   */
  public boolean isRegisteredEnvironment(final String token)
  {
    return environments.contains(token);
  }

  /**
   * Checks if the given token is a registered node.
   *
   * @param token the token to check.
   * @return <code>true</code> if the token is a registered node,
   *         <code>false</code> otherwise.
   */
  public boolean isRegisteredNode(final String token)
  {
    return nodes.contains(token);
  }

  /**
   * Checks if the given token is a registered group.
   *
   * @param token the token to check.
   * @return <code>true</code> if the token is a registered group,
   *         <code>false</code> otherwise.
   */
  public boolean isRegisteredGroup(final String token)
  {
    return groups.contains(token);
  }

  /**
   * Returns the configuration key associated with the given {@code path}.
   *
   * @param path the path to fetch its configuration key. Note that a
   *          <code>null</code> value is allowed.
   * @return the configuration key for the given {@code path} or
   *         <code>null</code> if no key is associated with it.
   */
  @CheckForNull
  public ConfigurationKey getKey(final String path)
  {
    return files.get(path);
  }

  /**
   * Checks if the given token is a group. It is a group if it is either
   * registered explicitly or the token starts with a registered TLD or it
   * starts with two letters and a dot.
   *
   * @param token the token to check.
   * @return <code>true</code> if the token is a group, <code>false</code>
   *         otherwise.
   */
  public boolean isGroup(final String token)
  {
    if (!isRegisteredGroup(token))
    {
      final String tld = determineTld(token);
      if (isRegisteredGroupTld(tld))
      {
        return true;
      }

      return false;
    }

    return true;
  }

  private String determineTld(final String token)
  {
    final int index = token.indexOf('.');
    if (index != -1)
    {
      return token.substring(0, index);
    }
    return null;
  }

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

  @Override
  public String toString()
  {
    final StringBuilder buffer = new StringBuilder(128);

    buffer.append("TLDs          :");
    for (final String tld : tlds)
    {
      buffer.append(' ').append(tld);
    }

    buffer.append("\nEnvironments  :");
    for (final String environment : environments)
    {
      buffer.append(' ').append(environment);
    }

    buffer.append("\nNodes         :");
    for (final String node : nodes)
    {
      buffer.append(' ').append(node);
    }

    buffer.append("\nGroups        :");
    for (final String group : groups)
    {
      buffer.append(' ').append(group);
    }

    buffer.append("\nExplicit Paths:");
    for (final Entry<String, ConfigurationKey> entry : files.entrySet())
    {
      buffer.append(' ').append(entry.getKey()).append('=')
          .append(entry.getValue());
    }

    return buffer.toString();
  }
}