|
1 package kawa.lang;
2 import gnu.mapping.*;
3 import gnu.expr.*;
4 import java.io.*;
5
6
11
12 public class AutoloadProcedure extends Procedure implements Externalizable
13 {
14
20 String  className;
21
22 Language language;
23
24
25 Procedure loaded;
26
27 public AutoloadProcedure ()
28 {
29 }
30
31 public AutoloadProcedure (String name, String className)
32 {
33 super(name);
34 this.className = className;
35 }
36
37 public AutoloadProcedure (String name, String className, Language language)
38 {
39 super(name);
40 this.className = className;
41 this.language = language;
42 }
43
44 public void print(java.io.PrintWriter ps)
45 {
46 ps.print ("#<procedure ");
47 String name = getName();
48 if (name != null)
49 {
50 ps.print (name);
51 }
53
62 ps.print ('>');
63 }
64
65 private void throw_error (String prefix)
66 {
67 loaded = null;
68 String name = getName();
69 throw new RuntimeException (prefix + className
70 + " while autoloading "
71 + (name == null ? "" : name.toString ()));
72 }
73
74
75 void load ()
76 {
77 Object name = this.getSymbol();
78 try
79 {
80 loaded = (Procedure) Class.forName (className).newInstance ();
81 if (loaded == this)
82 throw_error("circularity detected");
83 if (name != null)
84 {
85 try
86 {
87 Object property = (language.hasSeparateFunctionNamespace()
88 ? EnvironmentKey.FUNCTION
89 : null);
90 Environment env = language.getLangEnvironment();
92 Symbol sym = (name instanceof Symbol ? (Symbol) name
93 : env.getSymbol(name.toString()));
94 env.put(sym, property, loaded);
95 }
96 catch (UnboundLocationException ex)
97 {
98 }
99 if (loaded.getSymbol() == null)
100 loaded.setSymbol(name);
101 }
102 }
103 catch (ClassNotFoundException ex)
104 { throw_error ("failed to find class "); }
105 catch (InstantiationException ex)
106 { throw_error ("failed to instantiate class "); }
107 catch (IllegalAccessException ex)
108 { throw_error ("illegal access in class "); }
109 }
110
111 public Procedure getLoaded ()
112 {
113 if (loaded == null)
114 load();
115 return loaded;
116 }
117
118 public int numArgs ()
119 {
120 return getLoaded().numArgs();
121 }
122
123 public Object apply0 () throws Throwable
124 {
125 return getLoaded().apply0 ();
126 }
127
128 public Object apply1 (Object arg1) throws Throwable
129 {
130 return getLoaded().apply1 (arg1);
131 }
132
133 public Object apply2 (Object arg1,Object arg2) throws Throwable
134 {
135 return getLoaded().apply2 (arg1, arg2);
136 }
137
138 public Object apply3 (Object arg1, Object arg2, Object arg3) throws Throwable
139 {
140 return getLoaded().apply3 (arg1, arg2, arg3);
141 }
142
143 public Object apply4 (Object arg1, Object arg2,
144 Object arg3, Object arg4) throws Throwable
145 {
146 return getLoaded().apply4 (arg1, arg2, arg3, arg4);
147 }
148
149 public Object applyN (Object [] args) throws Throwable
150 {
151 if (loaded == null)
152 load ();
153 if (loaded instanceof AutoloadProcedure)
154 throw new InternalError ("circularity in autoload of "+getName());
155 return loaded.applyN (args);
156 }
157
158 public Procedure getSetter()
159 {
160 if (loaded == null)
161 load ();
162 if (loaded instanceof HasSetter)
163 return loaded.getSetter();
164 return super.getSetter();
165 }
166
167 public void writeExternal(ObjectOutput out) throws IOException
168 {
169 out.writeObject(getName());
170 out.writeObject(className);
171 }
172
173 public void readExternal(ObjectInput in)
174 throws IOException, ClassNotFoundException
175 {
176 setName((String ) in.readObject());
177 className = (String ) in.readObject();
178 }
179
180 public Object getProperty(Object key, Object defaultValue)
181 {
182 Object value = super.getProperty(key, null);
183 if (value != null)
184 return value;
185 return getLoaded().getProperty(key, defaultValue);
186 }
187 }
188 |
Popular Tags |
Java API By Example, From Geeks To Geeks.