67 lines
2.5 KiB
Java
67 lines
2.5 KiB
Java
/*
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* Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/**
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* Given an input object maps to an appropriate output object. A mapper may
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* variously provide a mapping between types, object instances or keys and
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* values or any other form of transformation upon the input.
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*
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* <p/>All mapper implementations are expected to:
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* <ul>
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* <li>Provide stable results such that for any {@code t} the result of two
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* {@code map} operations are always equivalent. ie.<pre>
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* Foo one = mapper.map(a);
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* Foo two = mapper.map(a);
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*
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* assert one.equals(two) && two.equals(one);
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* </pre></li>
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* <li>Equivalent input objects should map to equivalent output objects. ie.<pre>
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* assert a.equals(b); // a and b are equivalent
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*
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* Foo x = mapper.map(a);
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* Foo y = mapper.map(b);
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*
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* assert x.equals(y); // their mapped results should be as equivalent.
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* </pre></li>
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* <li>The mapper should not modify the input object in any way that would
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* change the mapping.</li>
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* <li>When used for aggregate operations upon many elements mappers
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* should not assume that the {@code map} operation will be called upon elements
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* in any specific order.</li>
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* </ul>
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*
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* @param <R> the type of output objects from {@code map} operation. May be the
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* @param <T> the type of input objects provided to the {@code map} operation.
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* same type as {@code <T>}.
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*/
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public interface TMapper<R, T> {
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/**
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* Map the provided input object to an appropriate output object.
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*
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* @param t the input object to be mapped.
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* @return the mapped output object.
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*/
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R map(T t);
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}
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