/
BTFunctorHandler.java
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/
BTFunctorHandler.java
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/*
* Copyright © 2019 Mark Raynsford <code@io7m.com> http://io7m.com
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR
* IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
package com.io7m.blackthorne.api;
import org.xml.sax.Attributes;
import java.util.Map;
import java.util.Objects;
import java.util.function.Function;
/**
* A handler that implements {@code fmap} for handlers.
*
* @param <A> The type of child values
* @param <B> The type of result values
* @param <C> The type of result values after a function is applied
*/
public final class BTFunctorHandler<A, B, C> implements BTElementHandlerType<A, C>
{
private final BTElementHandlerType<A, B> handler;
private final Function<B, C> function;
/**
* Construct a functor handler.
*
* @param inHandler The inner handler
* @param inFunction The mapping function
*/
public BTFunctorHandler(
final BTElementHandlerType<A, B> inHandler,
final Function<B, C> inFunction)
{
this.handler = Objects.requireNonNull(inHandler, "handler");
this.function = Objects.requireNonNull(inFunction, "function");
}
@Override
public Map<BTQualifiedName, BTElementHandlerConstructorType<?, ? extends A>> onChildHandlersRequested(
final BTElementParsingContextType context)
{
return this.handler.onChildHandlersRequested(context);
}
@Override
public String name()
{
return String.format("[map %s]", this.handler.name());
}
@Override
public BTIgnoreUnrecognizedElements onShouldIgnoreUnrecognizedElements(
final BTElementParsingContextType context)
{
return this.handler.onShouldIgnoreUnrecognizedElements(context);
}
@Override
public void onElementStart(
final BTElementParsingContextType context,
final Attributes attributes)
throws Exception
{
this.handler.onElementStart(context, attributes);
}
@Override
public void onChildValueProduced(
final BTElementParsingContextType context,
final A result)
throws Exception
{
this.handler.onChildValueProduced(context, result);
}
@Override
public void onCharacters(
final BTElementParsingContextType context,
final char[] data,
final int offset,
final int length)
throws Exception
{
this.handler.onCharacters(context, data, offset, length);
}
@Override
public C onElementFinished(final BTElementParsingContextType context)
throws Exception
{
return this.function.apply(this.handler.onElementFinished(context));
}
}