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Java > Open Source Codes > net > sf > jga > fn > algorithm > Merge


1 // ============================================================================
2 // $Id: Merge.java,v 1.6 2006/02/10 04:44:59 davidahall Exp $
3 // Copyright (c) 2003-2005 David A. Hall
4 // ============================================================================
5 // The contents of this file are subject to the Common Development and
6 // Distribution License (CDDL), Version 1.0 (the License); you may not use this
7 // file except in compliance with the License. You should have received a copy
8 // of the the License along with this file: if not, a copy of the License is
9 // available from Sun Microsystems, Inc.
10 //
11 // http://www.sun.com/cddl/cddl.html
12 //
13 // From time to time, the license steward (initially Sun Microsystems, Inc.) may
14 // publish revised and/or new versions of the License. You may not use,
15 // distribute, or otherwise make this file available under subsequent versions
16 // of the License.
17 //
18 // Alternatively, the contents of this file may be used under the terms of the
19 // GNU Lesser General Public License Version 2.1 or later (the "LGPL"), in which
20 // case the provisions of the LGPL are applicable instead of those above. If you
21 // wish to allow use of your version of this file only under the terms of the
22 // LGPL, and not to allow others to use your version of this file under the
23 // terms of the CDDL, indicate your decision by deleting the provisions above
24 // and replace them with the notice and other provisions required by the LGPL.
25 // If you do not delete the provisions above, a recipient may use your version
26 // of this file under the terms of either the CDDL or the LGPL.
27 //
28 // This library is distributed in the hope that it will be useful,
29 // but WITHOUT ANY WARRANTY; without even the implied warranty of
30 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
31 // ============================================================================
32 package net.sf.jga.fn.algorithm;
33
34 import java.util.Comparator JavaDoc;
35 import java.util.Iterator JavaDoc;
36 import net.sf.jga.fn.BinaryFunctor;
37 import net.sf.jga.util.MergeIterator;
38
39 /**
40  * Returns an iterator based on the two input iterators that will merge their
41  * contents. If the contents of both input iterators are sorted, then the
42  * iterator returned will be sorted as well.
43  * <p>
44  * To serialize a Merge, the comparator passed at construction must be
45  * Serializable.
46  * <p>
47  * Copyright &copy; 2003-2005 David A. Hall
48  * @deprecated
49  */
50
51 public class Merge<T>
52     extends BinaryFunctor<Iterator JavaDoc<? extends T>, Iterator JavaDoc<? extends T>,
53                                   MergeIterator<T>>
54 {
55     static final long serialVersionUID = 1680420131592467899L;
56
57     private Comparator JavaDoc<T> _comp;
58     
59     /**
60      * Builds an Merge functor that will use the given comparator to compare
61      * corresponding elements of two input iterators..
62      * @throws IllegalArgumentException if the test is null
63      */
64     public Merge(Comparator JavaDoc<T> comp) {
65         if (comp == null)
66             throw new IllegalArgumentException JavaDoc();
67
68         _comp = comp;
69     }
70
71     /**
72      * Returns the functor used to process elements in an iteration.
73      */
74     public Comparator JavaDoc<T> getComparator() {
75         return _comp;
76     }
77
78     /**
79      * Apply the functor to each element in the iteration and return an iterator
80      * over the results
81      *
82      * @return an iterator over the results of the transformation
83      */
84     public MergeIterator<T> fn(Iterator JavaDoc<? extends T> iter1,
85                                Iterator JavaDoc<? extends T> iter2)
86     {
87         return new MergeIterator<T>(iter1, iter2, _comp);
88     }
89     
90     /**
91      * Calls the Visitor's <code>visit(Merge)</code> method, if it
92      * implements the nested Visitor interface.
93      */
94     public void accept(net.sf.jga.fn.Visitor v) {
95         if (v instanceof Merge.Visitor)
96             ((Merge.Visitor)v).visit(this);
97         else
98             v.visit(this);
99     }
100
101     // Object overrides
102
103     public String JavaDoc toString() {
104         return "Merge";
105     }
106     
107     // AcyclicVisitor
108
109     /**
110      * Interface for classes that may interpret an <b>Merge</b> functor.
111      */
112     public interface Visitor extends net.sf.jga.fn.Visitor {
113         public void visit(Merge host);
114     }
115 }
116
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