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Functions.java
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Functions.java
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/*
* Copyright (c) 2002-2016 "Neo Technology,"
* Network Engine for Objects in Lund AB [http://neotechnology.com]
*
* This file is part of Neo4j.
*
* Neo4j is free software: you can redistribute it and/or modify
* it under the terms of the GNU 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 Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package org.neo4j.function;
import java.util.function.BiFunction;
import java.util.function.Function;
/**
* Constructors for basic {@link Function} and {@link BiFunction} types
* @deprecated This class relies on deprecated interfaces, and will be retrofitted to work with the {@code java.util.function} interfaces in 3.0.
*/
public final class Functions
{
public static <From, To> Function<From,To> withDefaults( final Function<From,To> defaults, final Function<From,
To> f )
{
return from -> {
To to = f.apply( from );
if ( to == null )
{
return defaults.apply( from );
}
else
{
return to;
}
};
}
public static <From, From2, To> BiFunction<? super Function<From,From2>,? super Function<From2,To>,Function<From,To>> compose()
{
return ( f1, f2 ) -> (Function<From,To>) from -> f2.apply( f1.apply( from ) );
}
public static <T1, T2> BiFunction<? super BiFunction<T1,T2,T1>,? super BiFunction<T1,T2,T1>,BiFunction<T1,T2,T1>> compose2()
{
return ( function1, function2 ) ->
( from1, from2 ) ->
function1.apply( function2.apply( from1, from2 ), from2 );
}
public static Function<Object,String> TO_STRING = from -> {
if ( from != null )
{
return from.toString();
}
else
{
return "";
}
};
}