| 1 | /* |
| 2 | |
| 3 | Derby - Class org.apache.derby.impl.services.bytecode.BCMethodDescriptor |
| 4 | |
| 5 | Copyright 1999, 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.bytecode; |
| 22 | |
| 23 | import org.apache.derby.iapi.services.classfile.VMDescriptor; |
| 24 | |
| 25 | /** |
| 26 | A method descriptor. Ie. something that describes the |
| 27 | type of a method, parameter types and return types. |
| 28 | It is not an instance of a method. |
| 29 | <BR> |
| 30 | This has no generated class specific state. |
| 31 | */ |
| 32 | class BCMethodDescriptor { |
| 33 | |
| 34 | static final String[] EMPTY = new String[0]; |
| 35 | |
| 36 | private final String[] vmParameterTypes; |
| 37 | private final String vmReturnType; |
| 38 | |
| 39 | private final String vmDescriptor; |
| 40 | |
| 41 | BCMethodDescriptor(String[] vmParameterTypes, String vmReturnType, BCJava factory) { |
| 42 | |
| 43 | this.vmParameterTypes = vmParameterTypes; |
| 44 | this.vmReturnType = vmReturnType; |
| 45 | |
| 46 | vmDescriptor = factory.vmType(this); |
| 47 | } |
| 48 | /* |
| 49 | static String get(Expression[] vmParameters, String vmReturnType, BCJava factory) { |
| 50 | |
| 51 | int count = vmParameters.length; |
| 52 | String[] vmParameterTypes; |
| 53 | if (count == 0) { |
| 54 | vmParameterTypes = BCMethodDescriptor.EMPTY; |
| 55 | } else { |
| 56 | vmParameterTypes = new String[count]; |
| 57 | for (int i =0; i < count; i++) { |
| 58 | vmParameterTypes[i] = ((BCExpr) vmParameters[i]).vmType(); |
| 59 | } |
| 60 | } |
| 61 | |
| 62 | return new BCMethodDescriptor(vmParameterTypes, vmReturnType, factory).toString(); |
| 63 | } |
| 64 | */ |
| 65 | static String get(String[] vmParameterTypes, String vmReturnType, BCJava factory) { |
| 66 | |
| 67 | return new BCMethodDescriptor(vmParameterTypes, vmReturnType, factory).toString(); |
| 68 | } |
| 69 | |
| 70 | /** |
| 71 | * builds the JVM method descriptor for this method as |
| 72 | * defined in JVM Spec 4.3.3, Method Descriptors. |
| 73 | */ |
| 74 | String buildMethodDescriptor() { |
| 75 | |
| 76 | int paramCount = vmParameterTypes.length; |
| 77 | |
| 78 | int approxLength = (30 * (paramCount + 1)); |
| 79 | |
| 80 | StringBuffer methDesc = new StringBuffer(approxLength); |
| 81 | |
| 82 | methDesc.append(VMDescriptor.C_METHOD); |
| 83 | |
| 84 | for (int i = 0; i < paramCount; i++) { |
| 85 | methDesc.append(vmParameterTypes[i]); |
| 86 | } |
| 87 | |
| 88 | methDesc.append(VMDescriptor.C_ENDMETHOD); |
| 89 | methDesc.append(vmReturnType); |
| 90 | |
| 91 | return methDesc.toString(); |
| 92 | } |
| 93 | |
| 94 | public String toString() { |
| 95 | return vmDescriptor; |
| 96 | } |
| 97 | |
| 98 | |
| 99 | public int hashCode() { |
| 100 | return vmParameterTypes.length | (vmReturnType.hashCode() & 0xFFFFFF00); |
| 101 | } |
| 102 | |
| 103 | public boolean equals(Object other) { |
| 104 | if (!(other instanceof BCMethodDescriptor)) |
| 105 | return false; |
| 106 | |
| 107 | BCMethodDescriptor o = (BCMethodDescriptor) other; |
| 108 | |
| 109 | |
| 110 | if (o.vmParameterTypes.length != vmParameterTypes.length) |
| 111 | return false; |
| 112 | |
| 113 | for (int i = 0; i < vmParameterTypes.length; i++) { |
| 114 | if (!vmParameterTypes[i].equals(o.vmParameterTypes[i])) |
| 115 | return false; |
| 116 | } |
| 117 | |
| 118 | return vmReturnType.equals(o.vmReturnType); |
| 119 | } |
| 120 | } |