001: // ============================================================================
002: // $Id: AndGenerator.java,v 1.8 2006/01/08 00:52:25 davidahall Exp $
003: // Copyright (c) 2002-2005 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.Generator;
036:
037: /**
038: * Generator that performs a shortcircuit and operation using a given pair
039: * of Boolean Generators. When the first generator returns true, the second
040: * is not evaluated.
041: **/
042:
043: public class AndGenerator extends Generator<Boolean> {
044:
045: static final long serialVersionUID = 6260506966868219143L;
046:
047: // The two generators that are tested
048: private Generator<Boolean> _first;
049: private Generator<Boolean> _second;
050:
051: /**
052: * Builds a AndGenerator functor, given the two functors that may be executed.
053: * @throws IllegalArgumentException if any of the functors is missing
054: */
055: public AndGenerator(Generator<Boolean> first,
056: Generator<Boolean> second) {
057: if (first == null || second == null) {
058: throw new IllegalArgumentException(
059: "Two functors are required");
060: }
061:
062: _first = first;
063: _second = second;
064: }
065:
066: public Generator<Boolean> getFirstFunctor() {
067: return _first;
068: }
069:
070: public Generator<Boolean> getSecondFunctor() {
071: return _second;
072: }
073:
074: public Boolean gen() {
075: return _first.gen() && _second.gen();
076: }
077:
078: /**
079: * Calls the Visitor's <code>visit(AndGenerator)</code> method, if it
080: * implements the nested Visitor interface.
081: */
082: public void accept(net.sf.jga.fn.Visitor v) {
083: if (v instanceof AndGenerator.Visitor)
084: ((AndGenerator.Visitor) v).visit(this );
085: else
086: v.visit(this );
087: }
088:
089: // Object overrides
090:
091: public String toString() {
092: return _first + " && " + _second;
093: }
094:
095: // AcyclicVisitor
096:
097: /**
098: * Interface for classes that may interpret an <b>AndGenerator</b> predicate.
099: */
100: public interface Visitor extends net.sf.jga.fn.Visitor {
101: public void visit(AndGenerator host);
102: }
103: }
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