br.com.objectos.comuns.io.AbstractColumn Maven / Gradle / Ivy

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/*
 * Copyright 2012 Objectos, Fábrica de Software LTDA.
 *
 * 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 br.com.objectos.comuns.io;

import java.util.Map;
import java.util.Objects;
import java.util.function.Supplier;

/**
 * @author [email protected] (Marcio Endo)
 */
public abstract class AbstractColumn implements Column {

  private final Map, ? extends ColumnConverter> converterMap;

  private final boolean nullOrEmpty;

  private final V value;

  public AbstractColumn(Map, ? extends ColumnConverter> converterMap, V value) {
    this.converterMap = converterMap;
    this.nullOrEmpty = isNullOrEmpty(value);
    this.value = cleanValue(value);
  }

  protected abstract boolean isNullOrEmpty(V value);

  protected abstract V cleanValue(V value);

  @Override
  public  T get(ColumnKey key) {
    return tryToConvert(key).get();
  }

  @Override
  public  T get(Class type) {
    return get(ColumnKey.of(type));
  }

  @Override
  public  T or(ColumnKey key, T instance) {
    return tryToConvert(key).or(instance);
  }

  @Override
  public  T or(Class type, T instance) {
    return or(ColumnKey.of(type), instance);
  }

  @Override
  public  T or(ColumnKey key, Supplier supplier) {
    return tryToConvert(key).or(supplier);
  }

  @Override
  public  T or(Class type, Supplier supplier) {
    return or(ColumnKey.of(type), supplier);
  }

  @Override
  public  T orNull(ColumnKey key) {
    return tryToConvert(key).orNull();
  }

  @Override
  public  T orNull(Class type) {
    return orNull(ColumnKey.of(type));
  }

  protected abstract String getNullOrEmptyMessage(V value);

  private void checkNullOrEmpty(ColumnKey key) {
    if (nullOrEmpty) {
      String msg = getNullOrEmptyMessage(value);
      throw new ColumnConversionException(msg, key.getType());
    }
  }

  private  ConversionTry tryToConvert(ColumnKey key) {
    checkKey(key);

    T value = null;
    ColumnConversionException exception = null;

    try {
      value = convert(key);
    } catch (ColumnConversionException e) {
      exception = e;
    }

    return new ConversionTry(key, exception, value);
  }

  private void checkKey(ColumnKey key) {
    Objects.requireNonNull(key, "key");

    if (!converterMap.containsKey(key)) {
      throw new IllegalArgumentException("No ColumnConverter bound to key: " + key);
    }
  }

  @SuppressWarnings("unchecked")
  private  T convert(ColumnKey key) {
    ColumnConverter converter = converterMap.get(key);
    return (T) converter.apply(value);
  }

  private class ConversionTry {

    private final ColumnKey key;

    private final ColumnConversionException e;

    private final T value;

    public ConversionTry(ColumnKey key, ColumnConversionException e, T value) {
      this.key = key;
      this.e = e;
      this.value = value;
    }

    public T get() {
      checkNullOrEmpty(key);
      return value;
    }

    public T or(T instance) {
      return error() ? instance : value;
    }

    public T or(Supplier supplier) {
      return error() ? supplier.get() : value;
    }

    public T orNull() {
      return error() ? null : value;
    }

    private boolean error() {
      return nullOrEmpty || e != null;
    }

  }

}