AbstractDateTimeConverter.java
package dev.orne.beans.converters;
/*-
* #%L
* Orne Beans
* %%
* Copyright (C) 2020 Orne Developments
* %%
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Lesser Public License for more details.
*
* You should have received a copy of the GNU General Lesser Public
* License along with this program. If not, see
* <http://www.gnu.org/licenses/lgpl-3.0.html>.
* #L%
*/
import java.time.DateTimeException;
import java.time.Instant;
import java.time.format.DateTimeFormatter;
import java.time.temporal.TemporalAccessor;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Collection;
import java.util.Collections;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;
import javax.validation.constraints.NotNull;
import org.apache.commons.beanutils.converters.AbstractConverter;
import org.apiguardian.api.API;
import org.apiguardian.api.API.Status;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Implementation of {@code Converter} that converts {@code LocalDate} instances
* to and from {@code String} using ISO-8601 as {@code String}
* representation by default.
*
* @author <a href="mailto:wamphiry@orne.dev">(w) Iker Hernaez</a>
* @version 1.0, 2020-05
* @since 0.1
*/
@API(status=Status.STABLE, since="0.1")
public abstract class AbstractDateTimeConverter
extends AbstractConverter {
/** The temporal value formatter. */
private final @NotNull DateTimeFormatter formatter;
/** The temporal value parsers. */
private final @NotNull Set<DateTimeFormatter> parsers = new LinkedHashSet<>();
/** The logger for this instance. */
private Logger logger;
/**
* Creates a new instance that throws a {@code ConversionException} if an
* error occurs.
*
* @param formatter The temporal value formatter and default parser
*/
protected AbstractDateTimeConverter(
final @NotNull DateTimeFormatter formatter) {
super();
this.formatter = formatter;
this.parsers.add(formatter);
}
/**
* Creates a new instance that returns a default value if an error occurs.
*
* @param formatter The temporal value formatter and default parser
* @param defaultValue The default value to be returned if the value to be
* converted is missing or an error occurs converting the value
*/
protected AbstractDateTimeConverter(
final @NotNull DateTimeFormatter formatter,
final TemporalAccessor defaultValue) {
super(defaultValue);
this.formatter = formatter;
this.parsers.add(formatter);
}
/**
* Returns the temporal value formatter and default parser.
*
* @return The temporal value formatter and default parser
*/
public @NotNull DateTimeFormatter getFormatter() {
return this.formatter;
}
/**
* Returns the extra temporal value parsers.
*
* @return The extra temporal value parsers
*/
public @NotNull List<DateTimeFormatter> getParsers() {
return Collections.unmodifiableList(new ArrayList<>(this.parsers));
}
/**
* Sets the temporal value parsers.
*
* @param parsers The temporal value parsers
*/
public void setParsers(
final @NotNull DateTimeFormatter... parsers) {
setParsers(Arrays.asList(parsers));
}
/**
* Sets the temporal value parsers.
*
* @param parsers The temporal value parsers
*/
public void setParsers(
final @NotNull Collection<DateTimeFormatter> parsers) {
this.parsers.clear();
this.parsers.addAll(parsers);
}
/**
* Adds specified parsers to the temporal value parsers.
*
* @param parsers The temporal value parsers to add
*/
public void addParsers(
final @NotNull DateTimeFormatter... parsers) {
addParsers(Arrays.asList(parsers));
}
/**
* Adds specified parsers to the temporal value parsers.
*
* @param parsers The temporal value parsers to add
*/
public void addParsers(
final @NotNull Collection<DateTimeFormatter> parsers) {
this.parsers.addAll(parsers);
}
/**
* {@inheritDoc}
*/
@Override
protected abstract Class<?> getDefaultType();
/**
* {@inheritDoc}
*/
@Override
protected <T> T convertToType(
final @NotNull Class<T> type,
final Object value) {
if (TemporalAccessor.class.isAssignableFrom(type)) {
@SuppressWarnings("unchecked")
final Class<? extends TemporalAccessor> temporalType =
(Class<? extends TemporalAccessor>) type;
if (value instanceof TemporalAccessor) {
return type.cast(fromTemporalAccessor(
temporalType,
(TemporalAccessor) value));
} else if (value instanceof Long) {
return type.cast(fromTemporalAccessor(
temporalType,
Instant.ofEpochMilli((long) value)));
} else if (value instanceof GregorianCalendar) {
return type.cast(fromTemporalAccessor(
temporalType,
((GregorianCalendar) value).toZonedDateTime()));
} else if (value instanceof Calendar) {
return type.cast(fromTemporalAccessor(
temporalType,
((Calendar) value).toInstant()));
} else if (value instanceof Date) {
return type.cast(fromTemporalAccessor(
temporalType,
((Date) value).toInstant()));
} else {
return type.cast(parseString(temporalType, value.toString()));
}
}
throw conversionException(type, value);
}
/**
* Tries to parse a {@code TemporalAccessor} of the specified type
* from the specified {@code String} value. Tries the parses in order
* calling {@link #parse(Class, DateTimeFormatter, String)}. If all
* parsers fail throws exception thrown by first parser.
*
* @param <T> The expected type of {@code TemporalAccessor}
* @param type The expected type of {@code TemporalAccessor}
* @param value The value to parse
* @return The parsed {@code TemporalAccessor} of the expected type
* @throws DateTimeException If the value cannot be parsed
*/
protected <T extends TemporalAccessor> T parseString(
final @NotNull Class<T> type,
final @NotNull String value) {
DateTimeException firstException = null;
for (final DateTimeFormatter parser : this.parsers) {
try {
return type.cast(parse(type, parser, value));
} catch (final DateTimeException dte) {
if (firstException == null) {
firstException = dte;
} else {
firstException.addSuppressed(dte);
}
getLogger().debug("Failed to parse temporal value", dte);
}
}
if (firstException == null) {
throw conversionException(type, value);
} else {
throw firstException;
}
}
/**
* Tries to parse a {@code TemporalAccessor} of the specified type
* from the specified value.
*
* @param <T> The expected type of {@code TemporalAccessor}
* @param type The expected type of {@code TemporalAccessor}
* @param parser The parser to use for parsing the value
* @param value The value to parse
* @return The parsed {@code TemporalAccessor} of the expected type
* @throws DateTimeException If the value cannot be parsed
*/
protected <T extends TemporalAccessor> T parse(
final @NotNull Class<T> type,
final @NotNull DateTimeFormatter parser,
final @NotNull String value) {
return fromTemporalAccessor(type, parser.parse(value));
}
/**
* Converts the {@code TemporalAccessor} passed as argument to the
* specified type.
*
* @param <T> The expected type of {@code TemporalAccessor}
* @param type The expected type of {@code TemporalAccessor}
* @param value The {@code TemporalAccessor} to convert to the
* expected type
* @return The converted {@code TemporalAccessor} of the expected type
* @throws DateTimeException If the value cannot be converted
*/
protected abstract <T extends TemporalAccessor> T fromTemporalAccessor(
@NotNull Class<T> type,
@NotNull TemporalAccessor value);
/**
* {@inheritDoc}
*/
@Override
protected String convertToString(
final Object value) {
if (value instanceof TemporalAccessor) {
return this.formatter.format((TemporalAccessor) value);
} else if (value instanceof String) {
return value.toString();
} else {
throw conversionException(String.class, value);
}
}
/**
* Returns the logger for this instance
*
* @return The logger for this instance
*/
protected @NotNull Logger getLogger() {
synchronized (this) {
if (this.logger == null) {
this.logger = LoggerFactory.getLogger(getClass());
}
return this.logger;
}
}
}