File	Doc	Category	Size	Date	Package
InstructionHandle.java	API Doc	Java SE 5 API	9346	Fri Aug 26 14:55:22 BST 2005	com.sun.org.apache.bcel.internal.generic

InstructionHandle

• java.lang.Object

Fields Summary
InstructionHandle	next
InstructionHandle	prev
Instruction	instruction
protected int	i_position
private HashSet	targeters
private HashMap	attributes
private static InstructionHandle	ih_list

Constructors Summary
protected InstructionHandle(Instruction i) setInstruction(i);

Methods Summary
public void	accept(com.sun.org.apache.bcel.internal.generic.Visitor v) Convenience method, simply calls accept() on the contained instruction. param v Visitor object instruction.accept(v);
public void	addAttribute(java.lang.Object key, java.lang.Object attr) Add an attribute to an instruction handle. param key the key object to store/retrieve the attribute param attr the attribute to associate with this handle if(attributes == null) attributes = new HashMap(3); attributes.put(key, attr);
protected void	addHandle() Overridden in BranchHandle next = ih_list; ih_list = this;
public void	addTargeter(com.sun.org.apache.bcel.internal.generic.InstructionTargeter t) Denote this handle is being referenced by t. if(targeters == null) targeters = new HashSet(); //if(!targeters.contains(t)) targeters.add(t);
void	dispose() Delete contents, i.e., remove user access and make handle reusable. next = prev = null; instruction.dispose(); instruction = null; i_position = -1; attributes = null; removeAllTargeters(); addHandle();
public java.lang.Object	getAttribute(java.lang.Object key) Get attribute of an instruction handle. param key the key object to store/retrieve the attribute if(attributes != null) return attributes.get(key); return null;
public java.util.Collection	getAttributes() return all attributes associated with this handle return attributes.values();
public final com.sun.org.apache.bcel.internal.generic.Instruction	getInstruction() return instruction;
static final com.sun.org.apache.bcel.internal.generic.InstructionHandle	getInstructionHandle(com.sun.org.apache.bcel.internal.generic.Instruction i) Factory method. // List of reusable handles if(ih_list == null) return new InstructionHandle(i); else { InstructionHandle ih = ih_list; ih_list = ih.next; ih.setInstruction(i); return ih; }
public final com.sun.org.apache.bcel.internal.generic.InstructionHandle	getNext() return next;
public int	getPosition() return the position, i.e., the byte code offset of the contained instruction. This is accurate only after InstructionList.setPositions() has been called. return i_position;
public final com.sun.org.apache.bcel.internal.generic.InstructionHandle	getPrev() return prev;
public com.sun.org.apache.bcel.internal.generic.InstructionTargeter[]	getTargeters() return null, if there are no targeters if(!hasTargeters()) return null; InstructionTargeter[] t = new InstructionTargeter[targeters.size()]; targeters.toArray(t); return t;
public boolean	hasTargeters() return (targeters != null) && (targeters.size() > 0);
public void	removeAllTargeters() Remove all targeters, if any. if(targeters != null) targeters.clear();
public void	removeAttribute(java.lang.Object key) Delete an attribute of an instruction handle. param key the key object to retrieve the attribute if(attributes != null) attributes.remove(key);
public void	removeTargeter(com.sun.org.apache.bcel.internal.generic.InstructionTargeter t) Denote this handle isn't referenced anymore by t. targeters.remove(t);
public void	setInstruction(com.sun.org.apache.bcel.internal.generic.Instruction i) Replace current instruction contained in this handle. Old instruction is disposed using Instruction.dispose(). // Overridden in BranchHandle if(i == null) throw new ClassGenException("Assigning null to handle"); if((this.getClass() != BranchHandle.class) && (i instanceof BranchInstruction)) throw new ClassGenException("Assigning branch instruction " + i + " to plain handle"); if(instruction != null) instruction.dispose(); instruction = i;
void	setPosition(int pos) Set the position, i.e., the byte code offset of the contained instruction. i_position = pos;
public com.sun.org.apache.bcel.internal.generic.Instruction	swapInstruction(com.sun.org.apache.bcel.internal.generic.Instruction i) Temporarily swap the current instruction, without disturbing anything. Meant to be used by a debugger, implementing breakpoints. Current instruction is returned. Instruction oldInstruction = instruction; instruction = i; return oldInstruction;
public java.lang.String	toString(boolean verbose) return a (verbose) string representation of the contained instruction. return Utility.format(i_position, 4, false, ' ") + ": " + instruction.toString(verbose);
public java.lang.String	toString() return a string representation of the contained instruction. return toString(true);
protected int	updatePosition(int offset, int max_offset) Called by InstructionList.setPositions when setting the position for every instruction. In the presence of variable length instructions `setPositions()' performs multiple passes over the instruction list to calculate the correct (byte) positions and offsets by calling this function. param offset additional offset caused by preceding (variable length) instructions param max_offset the maximum offset that may be caused by these instructions return additional offset caused by possible change of this instruction's length i_position += offset; return 0;