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/* 
 Copyright (C) GridGain Systems. All Rights Reserved.
 
 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
 
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 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.
 */

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 */

package org.gridgain.grid.util.lang;

import org.gridgain.grid.util.typedef.*;

/**
 * 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.
 * 
 * This form of predicate is essentially a syntactic "sugar" providing shorter syntax for:
 * 
 * ...
 * GridPredicate<GridTuple3<E1, E2, E3>>
 * ...
 * 
 * Type Alias
 * 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.
 * Thread Safety
 * 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  Type of the first free variable, i.e. the element the closure is called on.
 * @param  Type of the second free variable, i.e. the element the closure is called on.
 * @param  Type of the third free variable, i.e. the element the closure is called on.
 * @see P3
 * @see GridFunc
 */
public interface GridPredicate3 {
    /**
     * 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);
}