001: // ============================================================================
002: // $Id: CompoundBinary.java,v 1.4 2006/01/08 00:52:25 davidahall Exp $
003: // Copyright (c) 2005 David A. Hall
004: // ============================================================================
005: // The contents of this file are subject to the Common Development and
006: // Distribution License (CDDL), Version 1.0 (the License); you may not use this
007: // file except in compliance with the License. You should have received a copy
008: // of the the License along with this file: if not, a copy of the License is
009: // available from Sun Microsystems, Inc.
010: //
011: // http://www.sun.com/cddl/cddl.html
012: //
013: // From time to time, the license steward (initially Sun Microsystems, Inc.) may
014: // publish revised and/or new versions of the License. You may not use,
015: // distribute, or otherwise make this file available under subsequent versions
016: // of the License.
017: //
018: // Alternatively, the contents of this file may be used under the terms of the
019: // GNU Lesser General Public License Version 2.1 or later (the "LGPL"), in which
020: // case the provisions of the LGPL are applicable instead of those above. If you
021: // wish to allow use of your version of this file only under the terms of the
022: // LGPL, and not to allow others to use your version of this file under the
023: // terms of the CDDL, indicate your decision by deleting the provisions above
024: // and replace them with the notice and other provisions required by the LGPL.
025: // If you do not delete the provisions above, a recipient may use your version
026: // of this file under the terms of either the CDDL or the LGPL.
027: //
028: // This library is distributed in the hope that it will be useful,
029: // but WITHOUT ANY WARRANTY; without even the implied warranty of
030: // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
031: // ============================================================================
032:
033: package net.sf.jga.fn.adaptor;
034:
035: import net.sf.jga.fn.BinaryFunctor;
036:
037: /**
038: * Executes two BinaryFunctors, returning the results of the second.
039: * <p>
040: * Copyright © 2005 David A. Hall
041: */
042:
043: public class CompoundBinary<T1, T2, R> extends BinaryFunctor<T1, T2, R> {
044:
045: static final long serialVersionUID = -6716796579409524752L;
046:
047: // the first functor. Results of this functor are dropped
048: private BinaryFunctor<T1, T2, ?> _fn1;
049:
050: // the second functor. Results of this functor are returned.
051: private BinaryFunctor<T1, T2, R> _fn2;
052:
053: public CompoundBinary(BinaryFunctor<T1, T2, ?> fn1,
054: BinaryFunctor<T1, T2, R> fn2) {
055: if (fn1 == null || fn2 == null)
056: throw new IllegalArgumentException(
057: "Two functors are required");
058:
059: _fn1 = fn1;
060: _fn2 = fn2;
061: }
062:
063: /**
064: * @return the first of the two nested functors
065: */
066: public BinaryFunctor<T1, T2, ?> getFirstFunctor() {
067: return _fn1;
068: }
069:
070: /**
071: * @return the second of the two nested functors
072: */
073: public BinaryFunctor<T1, T2, R> getSecondFunctor() {
074: return _fn2;
075: }
076:
077: /**
078: * Executes both functors, returning the results of the second.
079: */
080: public R fn(T1 arg1, T2 arg2) {
081: _fn1.fn(arg1, arg2);
082: return _fn2.fn(arg1, arg2);
083: }
084:
085: /**
086: * Calls the Visitor's <code>visit(Constant)</code> method, if it
087: * implements the nested Visitor interface.
088: */
089: public void accept(net.sf.jga.fn.Visitor v) {
090: if (v instanceof CompoundBinary.Visitor)
091: ((CompoundBinary.Visitor) v).visit(this );
092: else
093: v.visit(this );
094: }
095:
096: // Object overrides
097:
098: public String toString() {
099: return _fn1 + "," + _fn2;
100: }
101:
102: // AcyclicVisitor
103:
104: /**
105: * Interface for classes that may interpret a <b>Constant</b> binaryFunctor.
106: */
107: public interface Visitor extends net.sf.jga.fn.Visitor {
108: public void visit(CompoundBinary host);
109: }
110: }
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