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JPA-like syntax for annotating POJO classes for persistence via Cassandra's Java driver - Implementation
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/*
 * Copyright (C) 2015-2015 The Helenus Driver Project Authors.
 *
 * 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.github.helenusdriver.driver.impl;

import com.github.helenusdriver.driver.Ordering;

/**
 * The OrderingImpl class extends Cassandra's
 * {@link com.datastax.driver.core.querybuilder.Ordering} to provide support for
 * POJOs.
 *
 * @copyright 2015-2015 The Helenus Driver Project Authors
 *
 * @author  The Helenus Driver Project Authors
 * @version 1 - Jan 19, 2015 - paouelle - Creation
 *
 * @since 1.0
 */
public class OrderingImpl
  extends Utils.Appendeable
  implements Ordering {
  /**
   * Holds the name of the column being ordered.
   *
   * @author paouelle
   */
  private final CharSequence name;

  /**
   * true if the order is descending; false otherwise.
   *
   * @author paouelle
   */
  private final boolean isDesc;

  /**
   * Instantiates a new OrderingImpl object.
   *
   * @author paouelle
   *
   * @param  name the column name
   * @param  isDesc true if the order is descending; false
   *         otherwise
   * @throws NullPointerException if name is null
   */
  OrderingImpl(CharSequence name, boolean isDesc) {
    org.apache.commons.lang3.Validate.notNull(name, "invalid null column name");
    this.name = name;
    this.isDesc = isDesc;
  }

  /**
   * {@inheritDoc}
   *
   * @author paouelle
   *
   * @see com.github.helenusdriver.driver.impl.Utils.Appendeable#appendTo(com.github.helenusdriver.driver.impl.TableInfoImpl, java.lang.StringBuilder)
   */
  @Override
  void appendTo(TableInfoImpl tinfo, StringBuilder sb) {
    Utils.appendName(name, sb);
    sb.append(isDesc ? " DESC" : " ASC");
  }

  /**
   * Gets the column name for this ordering.
   *
   * @author paouelle
   *
   * @return the column name for this ordering
   */
  CharSequence getColumnName() {
    return name;
  }

  /**
   * Checks if the order is descending.
   *
   * @author paouelle
   *
   * @return true if the order is descending; false
   *         otherwise
   */
  boolean isDescending() {
    return isDesc;
  }

  /**
   * Validates the clause using the specified table.
   *
   * @author paouelle
   *
   * @param  the type of POJO
   *
   * @param  table the non-null table to validate the ordering with
   * @throws IllegalArgumentException if the ordering is not valid
   */
   void validate(TableInfoImpl table) {
    table.validateColumn(name);
  }
}