| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.services.reflect.ReflectGeneratedClass |
| 4 | |
| 5 | Copyright 1998, 2004 The Apache Software Foundation or its licensors, as applicable. |
| 6 | |
| 7 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 8 | you may not use this file except in compliance with the License. |
| 9 | You may obtain a copy of the License at |
| 10 | |
| 11 | http://www.apache.org/licenses/LICENSE-2.0 |
| 12 | |
| 13 | Unless required by applicable law or agreed to in writing, software |
| 14 | distributed under the License is distributed on an "AS IS" BASIS, |
| 15 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 16 | See the License for the specific language governing permissions and |
| 17 | limitations under the License. |
| 18 | |
| 19 | */ |
| 20 | |
| 21 | package org.apache.derby.impl.services.reflect; |
| 22 | |
| 23 | import org.apache.derby.iapi.services.loader.GeneratedMethod; |
| 24 | import org.apache.derby.iapi.services.loader.GeneratedByteCode; |
| 25 | import org.apache.derby.iapi.services.loader.ClassFactory; |
| 26 | |
| 27 | import org.apache.derby.iapi.error.StandardException; |
| 28 | import org.apache.derby.iapi.reference.SQLState; |
| 29 | |
| 30 | import org.apache.derby.iapi.services.context.Context; |
| 31 | |
| 32 | import java.lang.reflect.Method; |
| 33 | import java.util.Hashtable; |
| 34 | |
| 35 | public final class ReflectGeneratedClass extends LoadedGeneratedClass { |
| 36 | |
| 37 | private final Hashtable methodCache; |
| 38 | private static final GeneratedMethod[] directs; |
| 39 | |
| 40 | |
| 41 | private final Class factoryClass; |
| 42 | private GCInstanceFactory factory; |
| 43 | |
| 44 | static { |
| 45 | directs = new GeneratedMethod[10]; |
| 46 | for (int i = 0; i < directs.length; i++) { |
| 47 | directs[i] = new DirectCall(i); |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | public ReflectGeneratedClass(ClassFactory cf, Class jvmClass, Class factoryClass) { |
| 52 | super(cf, jvmClass); |
| 53 | methodCache = new Hashtable(); |
| 54 | this.factoryClass = factoryClass; |
| 55 | } |
| 56 | |
| 57 | public Object newInstance(Context context) throws StandardException { |
| 58 | if (factoryClass == null) { |
| 59 | return super.newInstance(context); |
| 60 | } |
| 61 | |
| 62 | if (factory == null) { |
| 63 | |
| 64 | Throwable t; |
| 65 | try { |
| 66 | factory = (GCInstanceFactory) factoryClass.newInstance(); |
| 67 | t = null; |
| 68 | } catch (InstantiationException ie) { |
| 69 | t = ie; |
| 70 | } catch (IllegalAccessException iae) { |
| 71 | t = iae; |
| 72 | } catch (LinkageError le) { |
| 73 | t = le; |
| 74 | } |
| 75 | |
| 76 | if (t != null) |
| 77 | throw StandardException.newException(SQLState.GENERATED_CLASS_INSTANCE_ERROR, t, getName()); |
| 78 | } |
| 79 | |
| 80 | GeneratedByteCode ni = factory.getNewInstance(); |
| 81 | ni.initFromContext(context); |
| 82 | ni.setGC(this); |
| 83 | ni.postConstructor(); |
| 84 | return ni; |
| 85 | |
| 86 | } |
| 87 | |
| 88 | public GeneratedMethod getMethod(String simpleName) |
| 89 | throws StandardException { |
| 90 | |
| 91 | GeneratedMethod rm = (GeneratedMethod) methodCache.get(simpleName); |
| 92 | if (rm != null) |
| 93 | return rm; |
| 94 | |
| 95 | // Only look for methods that take no arguments |
| 96 | try { |
| 97 | if ((simpleName.length() == 2) && simpleName.startsWith("e")) { |
| 98 | |
| 99 | int id = ((int) simpleName.charAt(1)) - '0'; |
| 100 | |
| 101 | rm = directs[id]; |
| 102 | |
| 103 | |
| 104 | } |
| 105 | else |
| 106 | { |
| 107 | Method m = getJVMClass().getMethod(simpleName, (Class []) null); |
| 108 | |
| 109 | rm = new ReflectMethod(m); |
| 110 | } |
| 111 | methodCache.put(simpleName, rm); |
| 112 | return rm; |
| 113 | |
| 114 | } catch (NoSuchMethodException nsme) { |
| 115 | throw StandardException.newException(SQLState.GENERATED_CLASS_NO_SUCH_METHOD, |
| 116 | nsme, getName(), simpleName); |
| 117 | } |
| 118 | } |
| 119 | } |
| 120 | |
| 121 | class DirectCall implements GeneratedMethod { |
| 122 | |
| 123 | private final int which; |
| 124 | |
| 125 | DirectCall(int which) { |
| 126 | |
| 127 | this.which = which; |
| 128 | } |
| 129 | |
| 130 | public Object invoke(Object ref) |
| 131 | throws StandardException { |
| 132 | |
| 133 | try { |
| 134 | |
| 135 | GeneratedByteCode gref = (GeneratedByteCode) ref; |
| 136 | switch (which) { |
| 137 | case 0: |
| 138 | return gref.e0(); |
| 139 | case 1: |
| 140 | return gref.e1(); |
| 141 | case 2: |
| 142 | return gref.e2(); |
| 143 | case 3: |
| 144 | return gref.e3(); |
| 145 | case 4: |
| 146 | return gref.e4(); |
| 147 | case 5: |
| 148 | return gref.e5(); |
| 149 | case 6: |
| 150 | return gref.e6(); |
| 151 | case 7: |
| 152 | return gref.e7(); |
| 153 | case 8: |
| 154 | return gref.e8(); |
| 155 | case 9: |
| 156 | return gref.e9(); |
| 157 | } |
| 158 | return null; |
| 159 | } catch (StandardException se) { |
| 160 | throw se; |
| 161 | } |
| 162 | catch (Throwable t) { |
| 163 | throw StandardException.unexpectedUserException(t); |
| 164 | } |
| 165 | } |
| 166 | } |