org.cp.elements.data.conversion.converters.BooleanConverter Maven / Gradle / Ivy

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/*
 * Copyright 2011-Present Author or 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 org.cp.elements.data.conversion.converters;

import java.util.Collections;
import java.util.Set;

import org.cp.elements.data.conversion.ConversionException;
import org.cp.elements.data.conversion.Converter;
import org.cp.elements.data.conversion.DefaultableConverter;
import org.cp.elements.lang.annotation.Nullable;
import org.cp.elements.util.ArrayUtils;
import org.cp.elements.util.CollectionUtils;

/**
 * {@link BooleanConverter} converts an {@link Object} to a {@link Boolean}.
 *
 * @author John J. Blum
 * @see java.lang.Boolean
 * @see java.lang.Object
 * @see org.cp.elements.data.conversion.DefaultableConverter
 * @since 1.0.0
 */
@SuppressWarnings("unused")
public class BooleanConverter extends DefaultableConverter {

  protected final Set trueValues;

  /**
   * Constructs a new instance of {@link BooleanConverter}.
   */
  public BooleanConverter() {
    this(Boolean.TRUE.toString());
  }

  /**
   * Constructs a new instance of {@link BooleanConverter} initialized with an array of {@link String values}
   * representing {@literal true} values.
   *
   * @param trueValues array of {@link String values} representing {@literal true} values.
   */
  public BooleanConverter(String... trueValues) {
    this.trueValues = Collections.unmodifiableSet(CollectionUtils.asSet(ArrayUtils
      .nullSafeArray(trueValues, String.class)));
  }

  /**
   * Determines whether the given {@link Object value} is {@literal true}.
   *
   * @param value {@link Object} to evaluate.
   * @return a boolean value indicating whether the given {@link Object value} is {@literal true}.
   */
  protected boolean isTrue(@Nullable Object value) {

    String valueString = String.valueOf(value).trim();

    return Boolean.parseBoolean(valueString) || isTrue(valueString);
  }

  /**
   * Determines whether the given {@link String value} is {@literal true}.
   *
   * @param value {@link String} to evaluate.
   * @return a boolean value indicating whether the given {@link Object value} is {@literal true}.
   */
  protected boolean isTrue(@Nullable String value) {
    return this.trueValues.stream().anyMatch(trueValue -> trueValue.equalsIgnoreCase(value));
  }

  /**
   * Determines whether this {@link Converter} can convert {@link Object Objects}
   * {@link Class from type} {@link Class to type}.
   *
   * @param fromType {@link Class type} to convert from.
   * @param toType {@link Class type} to convert to.
   * @return a boolean indicating whether this {@link Converter} can convert {@link Object Objects}
   * {@link Class from type} {@link Class to type}.
   * @see org.cp.elements.data.conversion.ConversionService#canConvert(Class, Class)
   * @see #canConvert(Object, Class)
   */
  @Override
  public boolean canConvert(Class fromType, Class toType) {
    return Boolean.class.equals(toType) || Boolean.TYPE.equals(toType);
  }

  /**
   * Converts an {@link Object} of {@link Class type S} into an {@link Object} of {@link Class type T}.
   *
   * @param value {@link Object} of {@link Class type S} to convert.
   * @return the converted {@link Object} of {@link Class type T}.
   * @throws ConversionException if the {@link Object} cannot be converted.
   * @see org.cp.elements.data.conversion.ConversionService#convert(Object, Class)
   * @see #convert(Object, Class)
   */
  @Override
  public Boolean convert(Object value) {
    return value instanceof Boolean ? (Boolean) value
      : (isTrue(value) || Boolean.TRUE.equals(getDefaultValue()));
  }
}