/*
 * Copyright Terracotta, Inc.
 *
 * 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.ehcache.config.builders;

import java.util.concurrent.TimeUnit;

import org.ehcache.config.Builder;
import org.ehcache.impl.config.loaderwriter.writebehind.DefaultBatchingConfiguration;
import org.ehcache.impl.config.loaderwriter.writebehind.DefaultWriteBehindConfiguration;
import org.ehcache.spi.loaderwriter.WriteBehindConfiguration;
import org.ehcache.spi.loaderwriter.WriteBehindConfiguration.BatchingConfiguration;

The WriteBehindConfigurationBuilder enables building WriteBehindConfigurations using a fluent style. 

As with all Ehcache builders, all instances are immutable and calling any method on the builder will return a new
instance without modifying the one on which the method was called.
This enables the sharing of builder instances without any risk of seeing them modified by code elsewhere.
/**
 * The {@code WriteBehindConfigurationBuilder} enables building {@link WriteBehindConfiguration}s using a fluent style.
 * <p>
 * As with all Ehcache builders, all instances are immutable and calling any method on the builder will return a new
 * instance without modifying the one on which the method was called.
 * This enables the sharing of builder instances without any risk of seeing them modified by code elsewhere.
 */
public abstract class WriteBehindConfigurationBuilder implements Builder<WriteBehindConfiguration> {

  protected int concurrency = 1;
  protected int queueSize = Integer.MAX_VALUE;
  protected String threadPoolAlias = null;

  private WriteBehindConfigurationBuilder() {
  }

  private WriteBehindConfigurationBuilder(WriteBehindConfigurationBuilder other) {
    concurrency = other.concurrency;
    queueSize = other.queueSize;
    threadPoolAlias = other.threadPoolAlias;
  }

  
Creates a new builder for WriteBehindConfiguration that supports batching. 
Params:
maxDelay – the max delay for a batch
maxDelayUnit – the max delay unit
batchSize – the batch size
Returns:
a new builder/**
   * Creates a new builder for {@link WriteBehindConfiguration} that supports batching.
   *
   * @param maxDelay the max delay for a batch
   * @param maxDelayUnit the max delay unit
   * @param batchSize the batch size
   * @return a new builder
   */
  public static BatchedWriteBehindConfigurationBuilder newBatchedWriteBehindConfiguration(long maxDelay, TimeUnit maxDelayUnit, int batchSize) {
    return new BatchedWriteBehindConfigurationBuilder(maxDelay, maxDelayUnit, batchSize);
  }

  
Creates a new builder for WriteBehindConfiguration without batching support. 
Returns:
a new builder/**
   * Creates a new builder for {@link WriteBehindConfiguration} without batching support.
   *
   * @return a new builder
   */
  public static UnBatchedWriteBehindConfigurationBuilder newUnBatchedWriteBehindConfiguration() {
    return new UnBatchedWriteBehindConfigurationBuilder();
  }

  
Specialized WriteBehindConfigurationBuilder for WriteBehindConfigurations that supports batching /**
   * Specialized {@link WriteBehindConfigurationBuilder} for {@link WriteBehindConfiguration}s that supports batching
   */
  public static final class BatchedWriteBehindConfigurationBuilder extends WriteBehindConfigurationBuilder {
    private TimeUnit maxDelayUnit;
    private long maxDelay;
    private int batchSize;
    private boolean coalescing = false;

    private BatchedWriteBehindConfigurationBuilder(long maxDelay, TimeUnit maxDelayUnit, int batchSize) {
      setMaxWriteDelay(maxDelay, maxDelayUnit);
      setBatchSize(batchSize);
    }

    private BatchedWriteBehindConfigurationBuilder(BatchedWriteBehindConfigurationBuilder other) {
      super(other);
      maxDelay = other.maxDelay;
      maxDelayUnit = other.maxDelayUnit;
      coalescing = other.coalescing;
      batchSize = other.batchSize;
    }

    
Enables batch coalescing on the returned builder.
See Also:
disableCoalescing()
Returns:
a new builder with batch coalescing enabled/**
     * Enables batch coalescing on the returned builder.
     *
     * @return a new builder with batch coalescing enabled
     *
     * @see #disableCoalescing()
     */
    public BatchedWriteBehindConfigurationBuilder enableCoalescing() {
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.coalescing = true;
      return otherBuilder;
    }

    
Disables batch coalescing on the returned builder.
See Also:
enableCoalescing()
Returns:
a new buidler with batch coalescing disabled/**
     * Disables batch coalescing on the returned builder.
     *
     * @return a new buidler with batch coalescing disabled
     *
     * @see #enableCoalescing()
     */
    public BatchedWriteBehindConfigurationBuilder disableCoalescing() {
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.coalescing = false;
      return otherBuilder;
    }

    
Updates the batch size on the returned builder.
Params:
batchSize – the new batch size
Returns:
a new builder with updated batch size/**
     * Updates the batch size on the returned builder.
     *
     * @param batchSize the new batch size
     * @return a new builder with updated batch size
     */
    public BatchedWriteBehindConfigurationBuilder batchSize(int batchSize) {
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.setBatchSize(batchSize);
      return otherBuilder;
    }

    private void setBatchSize(int batchSize) throws IllegalArgumentException {
      if (batchSize < 1) {
        throw new IllegalArgumentException("Batch size must be a positive integer, was: " + batchSize);
      }
      this.batchSize = batchSize;
    }

    
Updates the max write delay on the returned builder.
Params:
maxDelay – the max delay amount
maxDelayUnit – the max delay unit
Returns:
a new builder with updated max write delay/**
     * Updates the max write delay on the returned builder.
     *
     * @param maxDelay the max delay amount
     * @param maxDelayUnit the max delay unit
     * @return a new builder with updated max write delay
     */
    public BatchedWriteBehindConfigurationBuilder maxWriteDelay(long maxDelay, TimeUnit maxDelayUnit) {
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.setMaxWriteDelay(maxDelay, maxDelayUnit);
      return otherBuilder;
    }

    private void setMaxWriteDelay(long maxDelay, TimeUnit maxDelayUnit) throws IllegalArgumentException {
      if (maxDelay < 1) {
        throw new IllegalArgumentException("Max batch delay must be positive, was: " + maxDelay + " " + maxDelayUnit);
      }
      this.maxDelay = maxDelay;
      this.maxDelayUnit = maxDelayUnit;
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public BatchedWriteBehindConfigurationBuilder queueSize(int size) {
      if (size < 1) {
        throw new IllegalArgumentException("Queue size must be positive, was: " + size);
      }
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.queueSize = size;
      return otherBuilder;
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public BatchedWriteBehindConfigurationBuilder concurrencyLevel(int concurrency) {
      if (concurrency < 1) {
        throw new IllegalArgumentException("Concurrency must be positive, was: " + concurrency);
      }
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.concurrency = concurrency;
      return otherBuilder;
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public BatchedWriteBehindConfigurationBuilder useThreadPool(String alias) {
      BatchedWriteBehindConfigurationBuilder otherBuilder = new BatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.threadPoolAlias = alias;
      return otherBuilder;
    }

    
Builds the WriteBehindConfiguration 
Returns:
the write behind configuration/**
     * Builds the {@link WriteBehindConfiguration}
     *
     * @return the write behind configuration
     */
    @Override
    public WriteBehindConfiguration build() {
      return buildWith(new DefaultBatchingConfiguration(maxDelay, maxDelayUnit, batchSize, coalescing));
    }
  }

  
Specialized WriteBehindConfigurationBuilder for WriteBehindConfigurations without batching support /**
   * Specialized {@link WriteBehindConfigurationBuilder} for {@link WriteBehindConfiguration}s without batching support
   */
  public static class UnBatchedWriteBehindConfigurationBuilder extends WriteBehindConfigurationBuilder {

    private UnBatchedWriteBehindConfigurationBuilder() {
    }

    private UnBatchedWriteBehindConfigurationBuilder(UnBatchedWriteBehindConfigurationBuilder other) {
      super(other);
    }

    
Builds the WriteBehindConfiguration 
Returns:
the write behind configuration/**
     * Builds the {@link WriteBehindConfiguration}
     *
     * @return the write behind configuration
     */
    @Override
    public WriteBehindConfiguration build() {
      return buildWith(null);
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public UnBatchedWriteBehindConfigurationBuilder queueSize(int size) {
      if (size < 1) {
        throw new IllegalArgumentException("Queue size must be positive, was: " + size);
      }
      UnBatchedWriteBehindConfigurationBuilder otherBuilder = new UnBatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.queueSize = size;
      return otherBuilder;
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public UnBatchedWriteBehindConfigurationBuilder concurrencyLevel(int concurrency) {
      if (concurrency < 1) {
        throw new IllegalArgumentException("Concurrency must be positive, was: " + concurrency);
      }
      UnBatchedWriteBehindConfigurationBuilder otherBuilder = new UnBatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.concurrency = concurrency;
      return otherBuilder;
    }

    
{@inheritDoc}
/**
     * {@inheritDoc}
     */
    @Override
    public UnBatchedWriteBehindConfigurationBuilder useThreadPool(String alias) {
      UnBatchedWriteBehindConfigurationBuilder otherBuilder = new UnBatchedWriteBehindConfigurationBuilder(this);
      otherBuilder.threadPoolAlias = alias;
      return otherBuilder;
    }
  }

  WriteBehindConfiguration buildWith(BatchingConfiguration batching) {
    return new DefaultWriteBehindConfiguration(threadPoolAlias, concurrency, queueSize, batching);
  }

  
Sets the batch queue size on the returned builder.
 Default queue size is Integer.MAX_VALUE. 
Params:
size – the new queue size
Returns:
a new builder with updated queue size/**
   * Sets the batch queue size on the returned builder.
   * <p>
   * Default queue size is {@link Integer#MAX_VALUE}.
   *
   * @param size the new queue size
   * @return a new builder with updated queue size
   */
  public abstract WriteBehindConfigurationBuilder queueSize(int size);

  
Sets the concurrency level on the returned builder.
 Default concurrency is 1. 
Params:
concurrency – the concurrency level
Returns:
a new builder with the new concurrency level/**
   * Sets the concurrency level on the returned builder.
   * <p>
   * Default concurrency is {@code 1}.
   *
   * @param concurrency the concurrency level
   * @return a new builder with the new concurrency level
   */
  public abstract WriteBehindConfigurationBuilder concurrencyLevel(int concurrency);

  
Sets the thread pool to use for write behind on the returned builder.
Params:
alias – the thread pool alias
See Also:
PooledExecutionServiceConfigurationBuilder
Returns:
a new builer with the configured thread pool alias/**
   * Sets the thread pool to use for write behind on the returned builder.
   *
   * @param alias the thread pool alias
   * @return a new builer with the configured thread pool alias
   *
   * @see PooledExecutionServiceConfigurationBuilder
   */
  public abstract WriteBehindConfigurationBuilder useThreadPool(String alias);
}