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package com.sun.org.apache.bcel.internal.generic;
BranchHandle is returned by specialized InstructionList.append() whenever a
BranchInstruction is appended. This is useful when the target of this
instruction is not known at time of creation and must be set later
via setTarget().
Author: M. Dahm See Also: - InstructionHandle
- Instruction
- InstructionList
/**
* BranchHandle is returned by specialized InstructionList.append() whenever a
* BranchInstruction is appended. This is useful when the target of this
* instruction is not known at time of creation and must be set later
* via setTarget().
*
* @see InstructionHandle
* @see Instruction
* @see InstructionList
* @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
*/
public final class BranchHandle extends InstructionHandle {
private BranchInstruction bi; // An alias in fact, but saves lots of casts
private BranchHandle(BranchInstruction i) {
super(i);
bi = i;
}
Factory methods.
/** Factory methods.
*/
private static BranchHandle bh_list = null; // List of reusable handles
static final BranchHandle getBranchHandle(BranchInstruction i) {
if(bh_list == null)
return new BranchHandle(i);
else {
BranchHandle bh = bh_list;
bh_list = (BranchHandle)bh.next;
bh.setInstruction(i);
return bh;
}
}
Handle adds itself to the list of resuable handles.
/** Handle adds itself to the list of resuable handles.
*/
protected void addHandle() {
next = bh_list;
bh_list = this;
}
/* Override InstructionHandle methods: delegate to branch instruction.
* Through this overriding all access to the private i_position field should
* be prevented.
*/
public int getPosition() { return bi.position; }
void setPosition(int pos) {
i_position = bi.position = pos;
}
protected int updatePosition(int offset, int max_offset) {
int x = bi.updatePosition(offset, max_offset);
i_position = bi.position;
return x;
}
Pass new target to instruction.
/**
* Pass new target to instruction.
*/
public void setTarget(InstructionHandle ih) {
bi.setTarget(ih);
}
Update target of instruction.
/**
* Update target of instruction.
*/
public void updateTarget(InstructionHandle old_ih, InstructionHandle new_ih) {
bi.updateTarget(old_ih, new_ih);
}
Returns: target of instruction.
/**
* @return target of instruction.
*/
public InstructionHandle getTarget() {
return bi.getTarget();
}
Set new contents. Old instruction is disposed and may not be used anymore.
/**
* Set new contents. Old instruction is disposed and may not be used anymore.
*/
public void setInstruction(Instruction i) {
super.setInstruction(i);
if(!(i instanceof BranchInstruction))
throw new ClassGenException("Assigning " + i +
" to branch handle which is not a branch instruction");
bi = (BranchInstruction)i;
}
}