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1
21
22 package org.armedbear.lisp;
23 import java.util.LinkedList  ;
24 import java.util.NoSuchElementException ;
25
26 public final class Mailbox extends LispObject
27 {
28
29 private LinkedList box = new LinkedList ();
30
31 private void send (LispObject o)
32 {
33 synchronized(this) {
34 box.add(o);
35 notifyAll();
36 }
37 }
38
39 private LispObject read ()
40 {
41 while (box.isEmpty())
42 synchronized(this) {
43 try {
44 wait();
45 } catch(InterruptedException e) {
46 throw new RuntimeException (e);
47 }
48 }
49 return (LispObject) box.removeFirst();
50 }
51
52 private LispObject peek ()
53 {
54 synchronized(this) {
55 try {
56 return (LispObject) box.getFirst();
57 } catch(NoSuchElementException e) {
58 return NIL;
59 }
60 }
61 }
62
63 private LispObject empty ()
64 {
65 return box.isEmpty() ? T : NIL;
66 }
67
68 public String toString()
69 {
70 StringBuffer sb = new StringBuffer ("#<MAILBOX @ #x");
71 sb.append(Integer.toHexString(hashCode()));
72 sb.append(">");
73 return sb.toString();
74 }
75
76
77 private static final Primitive0 MAKE_MAILBOX =
79 new Primitive0("make-mailbox", PACKAGE_EXT, true, "")
80 {
81 public LispObject execute() throws ConditionThrowable
82 {
83 return new Mailbox();
84 }
85 };
86
87 private static final Primitive2 MAILBOX_SEND =
89 new Primitive2("mailbox-send", PACKAGE_EXT, true, "mailbox object")
90 {
91 public LispObject execute(LispObject first, LispObject second) throws ConditionThrowable
92 {
93 if (first instanceof Mailbox) {
94 Mailbox mbox = (Mailbox) first;
95 mbox.send(second);
96 return T;
97 } else
98 return signal(new TypeError(first, "Mailbox"));
99 }
100 };
101
102 private static final Primitive1 MAILBOX_READ =
104 new Primitive1("mailbox-read", PACKAGE_EXT, true, "mailbox")
105 {
106 public LispObject execute(LispObject arg) throws ConditionThrowable
107 {
108 if (arg instanceof Mailbox) {
109 Mailbox mbox = (Mailbox) arg;
110 return mbox.read();
111 } else
112 return signal(new TypeError(arg, "Mailbox"));
113 }
114 };
115
116 private static final Primitive1 MAILBOX_PEEK =
118 new Primitive1("mailbox-peek", PACKAGE_EXT, true, "mailbox")
119 {
120 public LispObject execute(LispObject arg) throws ConditionThrowable
121 {
122 if (arg instanceof Mailbox) {
123 Mailbox mbox = (Mailbox) arg;
124 return mbox.peek();
125 } else
126 return signal(new TypeError(arg, "Mailbox"));
127 }
128 };
129
130 private static final Primitive1 MAILBOX_EMPTY_P =
132 new Primitive1("mailbox-empty-p", PACKAGE_EXT, true, "mailbox")
133 {
134 public LispObject execute(LispObject arg) throws ConditionThrowable
135 {
136 if (arg instanceof Mailbox) {
137 Mailbox mbox = (Mailbox) arg;
138 return mbox.empty();
139 } else
140 return signal(new TypeError(arg, "Mailbox"));
141 }
142 };
143 }
144
145 |
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