1 /* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5 /* 6 * Licensed to the Apache Software Foundation (ASF) under one or more 7 * contributor license agreements. See the NOTICE file distributed with 8 * this work for additional information regarding copyright ownership. 9 * The ASF licenses this file to You under the Apache License, Version 2.0 10 * (the "License"); you may not use this file except in compliance with 11 * the License. You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, software 16 * distributed under the License is distributed on an "AS IS" BASIS, 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 18 * See the License for the specific language governing permissions and 19 * limitations under the License. 20 */ 21 22 package com.sun.org.apache.bcel.internal.generic; 23 24 25 /** 26 * BranchHandle is returned by specialized InstructionList.append() whenever a 27 * BranchInstruction is appended. This is useful when the target of this 28 * instruction is not known at time of creation and must be set later 29 * via setTarget(). 30 * 31 * @see InstructionHandle 32 * @see Instruction 33 * @see InstructionList 34 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A> 35 */ 36 public final class BranchHandle extends InstructionHandle { 37 private BranchInstruction bi; // An alias in fact, but saves lots of casts 38 39 private BranchHandle(BranchInstruction i) { 40 super(i); 41 bi = i; 42 } 43 44 /** Factory methods. 45 */ 46 private static BranchHandle bh_list = null; // List of reusable handles 47 48 static final BranchHandle getBranchHandle(BranchInstruction i) { 49 if(bh_list == null) 50 return new BranchHandle(i); 51 else { 52 BranchHandle bh = bh_list; 53 bh_list = (BranchHandle)bh.next; 54 55 bh.setInstruction(i); 56 57 return bh; 58 } 59 } 60 61 /** Handle adds itself to the list of resuable handles. 62 */ 63 protected void addHandle() { 64 next = bh_list; 65 bh_list = this; 66 } 67 68 /* Override InstructionHandle methods: delegate to branch instruction. 69 * Through this overriding all access to the private i_position field should 70 * be prevented. 71 */ 72 public int getPosition() { return bi.position; } 73 74 void setPosition(int pos) { 75 i_position = bi.position = pos; 76 } 77 78 protected int updatePosition(int offset, int max_offset) { 79 int x = bi.updatePosition(offset, max_offset); 80 i_position = bi.position; 81 return x; 82 } 83 84 /** 85 * Pass new target to instruction. 86 */ 87 public void setTarget(InstructionHandle ih) { 88 bi.setTarget(ih); 89 } 90 91 /** 92 * Update target of instruction. 93 */ 94 public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) { 95 bi.updateTarget(old_ih, new_ih); 96 } 97 98 /** 99 * @return target of instruction. 100 */ 101 public InstructionHandle getTarget() { 102 return bi.getTarget(); 103 } 104 105 /** 106 * Set new contents. Old instruction is disposed and may not be used anymore. 107 */ 108 public void setInstruction(Instruction i) { 109 super.setInstruction(i); 110 111 if(!(i instanceof BranchInstruction)) 112 throw new ClassGenException("Assigning " + i + 113 " to branch handle which is not a branch instruction"); 114 115 bi = (BranchInstruction)i; 116 } 117 } | 1 /* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5 /* 6 * Licensed to the Apache Software Foundation (ASF) under one or more 7 * contributor license agreements. See the NOTICE file distributed with 8 * this work for additional information regarding copyright ownership. 9 * The ASF licenses this file to You under the Apache License, Version 2.0 10 * (the "License"); you may not use this file except in compliance with 11 * the License. You may obtain a copy of the License at 12 * 13 * http://www.apache.org/licenses/LICENSE-2.0 14 * 15 * Unless required by applicable law or agreed to in writing, software 16 * distributed under the License is distributed on an "AS IS" BASIS, 17 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 18 * See the License for the specific language governing permissions and 19 * limitations under the License. 20 */ 21 package com.sun.org.apache.bcel.internal.generic; 22 23 /** 24 * BranchHandle is returned by specialized InstructionList.append() whenever a 25 * BranchInstruction is appended. This is useful when the target of this 26 * instruction is not known at time of creation and must be set later via 27 * setTarget(). 28 * 29 * @see InstructionHandle 30 * @see Instruction 31 * @see InstructionList 32 * @version $Id: BranchHandle.java 1749603 2016-06-21 20:50:19Z ggregory $ 33 */ 34 public final class BranchHandle extends InstructionHandle { 35 36 // This is also a cache in case the InstructionHandle#swapInstruction() method is used 37 // See BCEL-273 38 private BranchInstruction bi; // An alias in fact, but saves lots of casts 39 40 private BranchHandle(final BranchInstruction i) { 41 super(i); 42 bi = i; 43 } 44 45 /** 46 * Factory methods. 47 */ 48 private static BranchHandle bh_list = null; // List of reusable handles 49 50 static BranchHandle getBranchHandle(final BranchInstruction i) { 51 if (bh_list == null) { 52 return new BranchHandle(i); 53 } 54 final BranchHandle bh = bh_list; 55 bh_list = (BranchHandle) bh.getNext(); 56 bh.setInstruction(i); 57 return bh; 58 } 59 60 /** 61 * Handle adds itself to the list of resuable handles. 62 */ 63 @Override 64 protected void addHandle() { 65 super.setNext(bh_list); 66 bh_list = this; 67 } 68 69 70 /* Override InstructionHandle methods: delegate to branch instruction. 71 * Through this overriding all access to the private i_position field should 72 * be prevented. 73 */ 74 @Override 75 public int getPosition() { 76 return bi.getPosition(); 77 } 78 79 @Override 80 void setPosition(final int pos) { 81 // Original code: i_position = bi.position = pos; 82 bi.setPosition(pos); 83 super.setPosition(pos); 84 } 85 86 @Override 87 protected int updatePosition(final int offset, final int max_offset) { 88 final int x = bi.updatePosition(offset, max_offset); 89 super.setPosition(bi.getPosition()); 90 return x; 91 } 92 93 /** 94 * Pass new target to instruction. 95 */ 96 public void setTarget(final InstructionHandle ih) { 97 bi.setTarget(ih); 98 } 99 100 /** 101 * Update target of instruction. 102 */ 103 public void updateTarget(final InstructionHandle old_ih, final InstructionHandle new_ih) { 104 bi.updateTarget(old_ih, new_ih); 105 } 106 107 /** 108 * @return target of instruction. 109 */ 110 public InstructionHandle getTarget() { 111 return bi.getTarget(); 112 } 113 114 /** 115 * Set new contents. Old instruction is disposed and may not be used 116 * anymore. 117 */ 118 @Override // This is only done in order to apply the additional type check; could be merged with super impl. 119 public void setInstruction(final Instruction i) { // TODO could be package-protected? 120 super.setInstruction(i); 121 if (!(i instanceof BranchInstruction)) { 122 throw new ClassGenException("Assigning " + i 123 + " to branch handle which is not a branch instruction"); 124 } 125 bi = (BranchInstruction) i; 126 } 127 } |