/*
    * #%L
    * wcm.io
    * %%
    * Copyright (C) 2014 wcm.io
    * %%
    * 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.
   * #L%
   */
  package io.wcm.caravan.io.jsontransform.element;
  
  import org.apache.commons.lang3.builder.EqualsBuilder;
  import org.apache.commons.lang3.builder.HashCodeBuilder;
  import org.apache.commons.lang3.builder.ToStringBuilder;
  import org.osgi.annotation.versioning.ProviderType;
  
  /**
   * A simple bean representing a JSON stream element.
   */
  @ProviderType
  public final class JsonElement {
  
    /**
     * The default JSON object start element
     */
    public static final JsonElement DEFAULT_START_OBJECT = new JsonElement(null, null, JsonElementType.START_OBJECT);
  
    /**
     * The default JSON array start element
     */
    public static final JsonElement DEFAULT_START_ARRAY = new JsonElement(null, null, JsonElementType.START_ARRAY);
  
    /**
     * The default JSON object end element
     */
    public static final JsonElement DEFAULT_END_OBJECT = new JsonElement(null, null, JsonElementType.END_OBJECT);
  
    /**
     * The default JSON array end element
     */
    public static final JsonElement DEFAULT_END_ARRAY = new JsonElement(null, null, JsonElementType.END_ARRAY);
  
    /**
     * The key of the JSON stream element. If {@link JsonElementType} is END_OBJECT or END_ARRAY will be null. Otherwise can be null.
     */
    private final String key;
  
    /**
     * The value of the JSON stream element. Only set for VALUE {@link JsonElementType}.
     */
    private final Object value;
  
    /**
     * The JSON stream element type.
     */
    private final JsonElementType type;
  
    /**
     * Creator for JSON value element with value being NULL.
     * @param key JSON element name
     * @return JSON value element with value NULL
     */
    public static JsonElement nullValue(String key) {
      return new JsonElement(key, null, JsonElementType.VALUE);
    }
  
    /**
     * Creator for JSON value element with given value and no key.
     * @param value JSON element value
     * @return JSON value element
     */
    public static JsonElement value(Object value) {
      return new JsonElement(null, value, JsonElementType.VALUE);
    }
  
    /**
     * Creator for JSON value element with given key and value
     * @param key JSON element name
     * @param value JSON element value
     * @return JSON value element
     */
    public static JsonElement value(String key, Object value) {
      return new JsonElement(key, value, JsonElementType.VALUE);
    }
  
    /**
     * Creator for JSON object start element with given key
     * @param key JSON element name
     * @return JSON object start element
    */
   public static JsonElement startObject(String key) {
     return new JsonElement(key, null, JsonElementType.START_OBJECT);
   }
 
   /**
    * Creator for JSON array start element with given key
    * @param key JSON element name
    * @return JSON array start element
    */
   public static JsonElement startArray(String key) {
     return new JsonElement(key, null, JsonElementType.START_ARRAY);
   }
 
   /**
    * @param key JSON element name
    * @param value JSON element value
    * @param type JSON element type
    */
   public JsonElement(String key, Object value, JsonElementType type) {
     this.key = key;
     this.value = value;
     this.type = type;
   }
 
   /**
    * @return the key
    */
   public String getKey() {
     return this.key;
   }
 
   /**
    * @return the value
    */
   public Object getValue() {
     return this.value;
   }
 
   /**
    * @return the type
    */
   public JsonElementType getType() {
     return this.type;
   }
 
   @Override
   public String toString() {
     return ToStringBuilder.reflectionToString(this);
   }
 
   @Override
   public int hashCode() {
     return HashCodeBuilder.reflectionHashCode(this, false);
   }
 
   @Override
   public boolean equals(Object obj) {
     return EqualsBuilder.reflectionEquals(this, obj, false);
   }
 
   /**
    * @return True if is a starting element
    */
   public boolean isStartingElement() {
     return JsonElementType.START_ARRAY.equals(type) || JsonElementType.START_OBJECT.equals(type);
   }
 
   /**
    * @return True if is a closing element
    */
   public boolean isClosingElement() {
     return JsonElementType.END_ARRAY.equals(type) || JsonElementType.END_OBJECT.equals(type);
   }
 
 }