/*
 * All content copyright Terracotta, Inc., unless otherwise indicated.
 *
 * 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 org.terracotta.statistics;

import org.terracotta.statistics.observer.OperationObserver;

import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

public final class StatisticBuilder {

  
Instantiates a new statistic builder.
/**
   * Instantiates a new statistic builder.
   */
  private StatisticBuilder() {

  }

  
Operation.
Params:
type – the type
Type parameters:
<T> –  the generic type
Returns:
the operation statistic builder/**
   * Operation.
   *
   * @param <T>  the generic type
   * @param type the type
   * @return the operation statistic builder
   */
  public static <T extends Enum<T>> OperationStatisticBuilder<T> operation(Class<T> type) {
    return new OperationStatisticBuilder<>(type);
  }

  
The Class OperationStatisticBuilder.
Type parameters:
<T> – the generic type/**
   * The Class OperationStatisticBuilder.
   *
   * @param <T> the generic type
   */
  public static class OperationStatisticBuilder<T extends Enum<T>> extends
      AbstractStatisticBuilder<OperationStatisticBuilder<T>> {

    
The type.
/**
     * The type.
     */
    private final Class<T> type;

    
Instantiates a new operation statistic builder.
Params:
type – the type/**
     * Instantiates a new operation statistic builder.
     *
     * @param type the type
     */
    public OperationStatisticBuilder(Class<T> type) {
      this.type = type;
    }

    
Builds the.
Returns:
the operation observer/**
     * Builds the.
     *
     * @return the operation observer
     */
    public OperationObserver<T> build() {
      if (context == null || name == null) {
        throw new IllegalStateException();
      } else {
        return StatisticsManager.createOperationStatistic(context, name, tags, properties, type);
      }
    }
  }

  
The Class AbstractStatisticBuilder.
Type parameters:
<T> – the generic type/**
   * The Class AbstractStatisticBuilder.
   *
   * @param <T> the generic type
   */
  static class AbstractStatisticBuilder<T extends AbstractStatisticBuilder<T>> {

    
The tags.
/**
     * The tags.
     */
    protected final Set<String> tags = new HashSet<>();

    
The properties.
/**
     * The properties.
     */
    protected final Map<String, Object> properties = new HashMap<>();

    
The context.
/**
     * The context.
     */
    protected Object context;

    
The name.
/**
     * The name.
     */
    protected String name;

    
Of.
Params:
of – the of
Returns:
the builder/**
     * Of.
     *
     * @param of the of
     * @return the builder
     */
    @SuppressWarnings("unchecked")
    public T of(Object of) {
      if (context == null) {
        context = of;
        return (T) this;
      } else {
        throw new IllegalStateException("Context already defined");
      }
    }

    
Named.
Params:
name – the name
Returns:
the builder/**
     * Named.
     *
     * @param name the name
     * @return the builder
     */
    @SuppressWarnings("unchecked")
    public T named(String name) {
      if (this.name == null) {
        this.name = name;
        return (T) this;
      } else {
        throw new IllegalStateException("Name already defined");
      }
    }

    
Tag.
Params:
tags – the tags
Returns:
the builder/**
     * Tag.
     *
     * @param tags the tags
     * @return the builder
     */
    @SuppressWarnings("unchecked")
    public T tag(String... tags) {
      Collections.addAll(this.tags, tags);
      return (T) this;
    }

    
Tag.
Params:
key –   the property key
value – the property value
Returns:
the builder/**
     * Tag.
     *
     * @param key   the property key
     * @param value the property value
     * @return the builder
     */
    @SuppressWarnings("unchecked")
    public T property(String key, Object value) {
      this.properties.put(key, value);
      return (T) this;
    }
  }
}