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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().
See Also:
Version:$Id: BranchHandle.java 1749603 2016-06-21 20:50:19Z ggregory $
/** * 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 * @version $Id: BranchHandle.java 1749603 2016-06-21 20:50:19Z ggregory $ */
public final class BranchHandle extends InstructionHandle { // This is also a cache in case the InstructionHandle#swapInstruction() method is used // See BCEL-273 private BranchInstruction bi; // An alias in fact, but saves lots of casts private BranchHandle(final BranchInstruction i) { super(i); bi = i; }
Factory methods.
/** * Factory methods. */
private static BranchHandle bh_list = null; // List of reusable handles static BranchHandle getBranchHandle(final BranchInstruction i) { if (bh_list == null) { return new BranchHandle(i); } final BranchHandle bh = bh_list; bh_list = (BranchHandle) bh.getNext(); bh.setInstruction(i); return bh; }
Handle adds itself to the list of resuable handles.
/** * Handle adds itself to the list of resuable handles. */
@Override protected void addHandle() { super.setNext(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. */ @Override public int getPosition() { return bi.getPosition(); } @Override void setPosition(final int pos) { // Original code: i_position = bi.position = pos; bi.setPosition(pos); super.setPosition(pos); } @Override protected int updatePosition(final int offset, final int max_offset) { final int x = bi.updatePosition(offset, max_offset); super.setPosition(bi.getPosition()); return x; }
Pass new target to instruction.
/** * Pass new target to instruction. */
public void setTarget(final InstructionHandle ih) { bi.setTarget(ih); }
Update target of instruction.
/** * Update target of instruction. */
public void updateTarget(final InstructionHandle old_ih, final 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. */
@Override // This is only done in order to apply the additional type check; could be merged with super impl. public void setInstruction(final Instruction i) { // TODO could be package-protected? super.setInstruction(i); if (!(i instanceof BranchInstruction)) { throw new ClassGenException("Assigning " + i + " to branch handle which is not a branch instruction"); } bi = (BranchInstruction) i; } }