GridPredicate3.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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,
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 * See the License for the specific language governing permissions and
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package org.apache.ignite.internal.util.lang;

import org.apache.ignite.internal.util.typedef.P3;

/**
 * Defines predicate construct. Predicate like closure is a first-class function
 * that is defined with (or closed over) its free variables that are bound to the closure
 * scope at execution.
 * <p>
 * This form of predicate is essentially a syntactic "sugar" providing shorter syntax for:
 * <pre name="code" class="java">
 * ...
 * GridPredicate<GridTuple3<E1, E2, E3>>
 * ...
 * </pre>
 * <h2 class="header">Type Alias</h2>
 * To provide for more terse code you can use a typedef {@link P3} class or various factory methods in
 * {@link GridFunc} class. Note, however, that since typedefs in Java rely on inheritance you should
 * not use these type aliases in signatures.
 * <h2 class="header">Thread Safety</h2>
 * Note that this interface does not impose or assume any specific thread-safety by its
 * implementations. Each implementation can elect what type of thread-safety it provides,
 * if any.
 * @param <E1> Type of the first free variable, i.e. the element the closure is called on.
 * @param <E2> Type of the second free variable, i.e. the element the closure is called on.
 * @param <E3> Type of the third free variable, i.e. the element the closure is called on.
 * @see P3
 * @see GridFunc
 */
public interface GridPredicate3<E1, E2, E3> {
    /**
     * Predicate body.
     *
     * @param e1 First bound free variable, i.e. the element the closure is called or closed on.
     * @param e2 Second bound free variable, i.e. the element the closure is called or closed on.
     * @param e3 Third bound free variable, i.e. the element the closure is called or closed on.
     * @return Return value.
     */
    public abstract boolean apply(E1 e1, E2 e2, E3 e3);
}