1 | /* |
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2 | * JProxy.java |
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3 | * |
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4 | * Copyright (C) 2002-2005 Peter Graves, Andras Simon |
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5 | * $Id: JProxy.java 14466 2013-04-24 12:50:40Z rschlatte $ |
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6 | * |
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7 | * This program is free software; you can redistribute it and/or |
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8 | * modify it under the terms of the GNU General Public License |
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9 | * as published by the Free Software Foundation; either version 2 |
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10 | * of the License, or (at your option) any later version. |
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11 | * |
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12 | * This program is distributed in the hope that it will be useful, |
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | * GNU General Public License for more details. |
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16 | * |
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17 | * You should have received a copy of the GNU General Public License |
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18 | * along with this program; if not, write to the Free Software |
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19 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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20 | * |
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21 | * As a special exception, the copyright holders of this library give you |
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22 | * permission to link this library with independent modules to produce an |
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23 | * executable, regardless of the license terms of these independent |
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24 | * modules, and to copy and distribute the resulting executable under |
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25 | * terms of your choice, provided that you also meet, for each linked |
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26 | * independent module, the terms and conditions of the license of that |
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27 | * module. An independent module is a module which is not derived from |
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28 | * or based on this library. If you modify this library, you may extend |
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29 | * this exception to your version of the library, but you are not |
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30 | * obligated to do so. If you do not wish to do so, delete this |
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31 | * exception statement from your version. |
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32 | */ |
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33 | |
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34 | package org.armedbear.lisp; |
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35 | |
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36 | import static org.armedbear.lisp.Lisp.*; |
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37 | |
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38 | import java.lang.reflect.InvocationHandler; |
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39 | import java.lang.reflect.Method; |
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40 | import java.lang.reflect.Proxy; |
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41 | import java.util.HashMap; |
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42 | import java.util.Map; |
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43 | import java.util.WeakHashMap; |
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44 | |
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45 | public final class JProxy |
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46 | { |
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47 | static final Map<Object,Entry> table = new WeakHashMap<Object,Entry>(); |
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48 | |
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49 | // ### %jnew-proxy interface &rest method-names-and-defs |
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50 | private static final Primitive _JNEW_PROXY = |
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51 | new Primitive("%jnew-proxy", PACKAGE_JAVA, false, |
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52 | "interface &rest method-names-and-defs") |
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53 | { |
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54 | @Override |
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55 | public LispObject execute(LispObject[] args) |
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56 | { |
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57 | int length = args.length; |
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58 | if (length < 3 || length % 2 != 1) |
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59 | return error(new WrongNumberOfArgumentsException(this)); |
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60 | Map<String,Function> lispDefinedMethods = new HashMap<String,Function>(); |
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61 | for (int i = 1; i < length; i += 2) |
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62 | lispDefinedMethods.put(args[i].getStringValue(), |
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63 | (Function) args[i + 1]); |
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64 | Class iface = (Class) args[0].javaInstance(); |
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65 | Object proxy = Proxy.newProxyInstance(iface.getClassLoader(), |
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66 | new Class[] { iface }, |
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67 | new LispHandler(table)); |
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68 | table.put(proxy, new Entry(iface, lispDefinedMethods)); |
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69 | return new JavaObject(proxy); |
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70 | } |
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71 | }; |
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72 | |
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73 | private static class LispHandler implements InvocationHandler |
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74 | { |
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75 | Map table; |
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76 | |
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77 | LispHandler (Map table) |
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78 | { |
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79 | this.table = table; |
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80 | } |
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81 | |
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82 | public Object invoke(Object proxy, Method method, Object[] args) |
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83 | { |
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84 | String methodName = method.getName(); |
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85 | |
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86 | if (methodName.equals("hashCode")) |
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87 | return new Integer(System.identityHashCode(proxy)); |
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88 | if (methodName.equals("equals")) |
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89 | return (proxy == args[0] ? Boolean.TRUE : Boolean.FALSE); |
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90 | if (methodName.equals("toString")) |
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91 | return proxy.getClass().getName() + '@' + Integer.toHexString(proxy.hashCode()); |
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92 | |
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93 | if (table.containsKey(proxy)) |
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94 | { |
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95 | Entry entry = (Entry) table.get(proxy); |
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96 | Function f = entry.getLispMethod(methodName); |
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97 | if (f != null) |
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98 | { |
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99 | LispObject lispArgs = NIL; |
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100 | if (args != null) |
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101 | { |
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102 | for (int i = args.length - 1 ; 0 <= i ; i--) |
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103 | lispArgs = lispArgs.push(new JavaObject(args[i])); |
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104 | } |
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105 | LispObject result = evalCall(f, lispArgs, new Environment(), |
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106 | LispThread.currentThread()); |
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107 | return (method.getReturnType() == void.class ? null : result.javaInstance()); |
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108 | } |
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109 | } |
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110 | return null; |
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111 | } |
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112 | } |
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113 | |
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114 | private static class Entry |
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115 | { |
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116 | Class iface; |
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117 | Map lispDefinedMethods; |
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118 | |
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119 | public Entry (Class iface, Map lispDefinedMethods) |
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120 | { |
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121 | this.iface = iface; |
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122 | this.lispDefinedMethods = lispDefinedMethods; |
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123 | } |
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124 | |
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125 | public Function getLispMethod(String methodName) |
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126 | { |
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127 | if (lispDefinedMethods.containsKey(methodName)) |
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128 | return (Function)lispDefinedMethods.get(methodName); |
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129 | return null; |
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130 | } |
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131 | } |
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132 | |
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133 | //NEW IMPLEMENTATION by Alessio Stalla |
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134 | |
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135 | /** |
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136 | * A weak map associating each proxy instance with a "Lisp-this" object. |
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137 | */ |
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138 | static final Map<Object, LispObject> proxyMap = new WeakHashMap<Object, LispObject>(); |
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139 | |
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140 | public static class LispInvocationHandler implements InvocationHandler { |
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141 | |
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142 | private Function function; |
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143 | private static Method hashCodeMethod; |
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144 | private static Method equalsMethod; |
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145 | private static Method toStringMethod; |
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146 | |
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147 | static { |
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148 | try { |
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149 | hashCodeMethod = Object.class.getMethod("hashCode", new Class[] {}); |
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150 | equalsMethod = Object.class.getMethod("equals", new Class[] { Object.class }); |
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151 | toStringMethod = Object.class.getMethod("toString", new Class[] {}); |
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152 | } catch (Exception e) { |
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153 | throw new Error("Something got horribly wrong - can't get a method from Object.class", e); |
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154 | } |
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155 | } |
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156 | |
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157 | public LispInvocationHandler(Function function) { |
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158 | this.function = function; |
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159 | } |
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160 | |
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161 | public Object invoke(Object proxy, Method method, Object[] args) throws Throwable { |
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162 | if(hashCodeMethod.equals(method)) { |
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163 | return System.identityHashCode(proxy); |
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164 | } |
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165 | if(equalsMethod.equals(method)) { |
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166 | return proxy == args[0]; |
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167 | } |
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168 | if(toStringMethod.equals(method)) { |
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169 | return proxy.getClass().getName() + '@' + Integer.toHexString(proxy.hashCode()); |
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170 | } |
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171 | |
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172 | if(args == null) { |
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173 | args = new Object[0]; |
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174 | } |
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175 | LispObject lispArgs = NIL; |
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176 | synchronized(proxyMap) { |
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177 | lispArgs = lispArgs.push(toLispObject(proxyMap.get(proxy))); |
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178 | } |
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179 | lispArgs = lispArgs.push(new SimpleString(method.getName())); |
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180 | for(int i = 0; i < args.length; i++) { |
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181 | lispArgs = lispArgs.push(toLispObject(args[i])); |
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182 | } |
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183 | Object retVal = |
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184 | LispThread.currentThread().execute |
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185 | (Symbol.APPLY, function, lispArgs.reverse()).javaInstance(); |
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186 | //(function.execute(lispArgs)).javaInstance(); |
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187 | /* DOES NOT WORK due to autoboxing! |
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188 | if(retVal != null && !method.getReturnType().isAssignableFrom(retVal.getClass())) { |
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189 | return error(new TypeError(new JavaObject(retVal), new JavaObject(method.getReturnType()))); |
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190 | }*/ |
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191 | return retVal; |
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192 | } |
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193 | } |
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194 | |
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195 | private static final Primitive _JMAKE_INVOCATION_HANDLER = |
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196 | new Primitive("%jmake-invocation-handler", PACKAGE_JAVA, false, |
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197 | "function") { |
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198 | |
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199 | public LispObject execute(LispObject[] args) { |
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200 | int length = args.length; |
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201 | if (length != 1) { |
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202 | return error(new WrongNumberOfArgumentsException(this, 1)); |
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203 | } |
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204 | if(!(args[0] instanceof Function)) { |
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205 | return type_error(args[0], Symbol.FUNCTION); |
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206 | } |
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207 | return new JavaObject(new LispInvocationHandler((Function) args[0])); |
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208 | } |
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209 | }; |
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210 | |
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211 | private static final Primitive _JMAKE_PROXY = |
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212 | new Primitive("%jmake-proxy", PACKAGE_JAVA, false, |
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213 | "interfaces invocation-handler") { |
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214 | |
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215 | public LispObject execute(final LispObject[] args) { |
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216 | int length = args.length; |
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217 | if (length != 3) { |
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218 | return error(new WrongNumberOfArgumentsException(this, 3)); |
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219 | } |
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220 | if(!(args[0] instanceof Cons)) { |
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221 | return type_error(args[0], Symbol.CONS); |
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222 | } |
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223 | Class[] ifaces = new Class[args[0].length()]; |
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224 | LispObject ifList = args[0]; |
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225 | for(int i = 0; i < ifaces.length; i++) { |
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226 | ifaces[i] = (Class) ifList.car().javaInstance(Class.class); |
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227 | ifList = ifList.cdr(); |
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228 | } |
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229 | InvocationHandler invocationHandler = (InvocationHandler) ((JavaObject) args[1]).javaInstance(InvocationHandler.class); |
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230 | Object proxy = Proxy.newProxyInstance( |
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231 | JavaClassLoader.getCurrentClassLoader(), |
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232 | ifaces, |
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233 | invocationHandler); |
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234 | synchronized(proxyMap) { |
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235 | proxyMap.put(proxy, args[2]); |
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236 | } |
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237 | return new JavaObject(proxy); |
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238 | } |
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239 | }; |
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240 | |
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241 | static LispObject toLispObject(Object obj) { |
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242 | return (obj instanceof LispObject) ? (LispObject) obj : new JavaObject(obj); |
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243 | } |
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244 | |
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245 | } |
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