com.helger.html.hc.IHCHasID Maven / Gradle / Ivy

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/**
 * Copyright (C) 2014-2016 Philip Helger (www.helger.com)
 * philip[at]helger[dot]com
 *
 * 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 com.helger.html.hc;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import com.helger.commons.id.factory.GlobalIDFactory;
import com.helger.commons.string.StringHelper;
import com.helger.commons.traits.IGenericImplTrait;

/**
 * Special interface for HC elements having an optional ID
 *
 * @author Philip Helger
 * @param 
 *        The implementation type
 */
public interface IHCHasID > extends IGenericImplTrait 
{
  /**
   * Get the HTML ID of this object.

   * Note: we cannot use IHasID<String> because the
   * constraint of IHasID is, that the returned ID may not be null
   * whereas here the HTML ID can be null!
   *
   * @return The HTML ID of this object.
   */
  @Nullable
  String getID ();

  /**
   * @return true if this element has an ID, false if
   *         not.
   */
  default boolean hasID ()
  {
    return StringHelper.hasText (getID ());
  }

  /**
   * @return true if this element has no ID, false if
   *         it has one.
   */
  default boolean hasNoID ()
  {
    return StringHelper.hasNoText (getID ());
  }

  /**
   * Set the HTML ID of this object.
   *
   * @param sID
   *        The ID to use. Must conform to the HTML rules for an element ID.
   * @return this
   */
  @Nonnull
  IMPLTYPE setID (@Nullable String sID);

  /**
   * Set a unique HTML ID for this object. Equal to
   * setID (GlobalIDFactory.getNewStringID ())
   *
   * @return this
   */
  @Nonnull
  default IMPLTYPE setUniqueID ()
  {
    return setID (GlobalIDFactory.getNewStringID ());
  }

  /**
   * Set a new ID if none is present. This is a shortcut for
   * if (!hasID())setUniqueID ();
   *
   * @return this
   */
  @Nonnull
  default IMPLTYPE ensureID ()
  {
    if (!hasID ())
      setUniqueID ();
    return thisAsT ();
  }
}