org.objectweb.asm.Opcodes# LOOKUPSWITCH 源码实例Demo

public InsnValue getSwitchValue(AbstractInsnNode insn, InsnValue value) {
	if (value.getValue() == null) {
		return InsnValue.intValue(-1);
	}
	int i = (int) value.getValue();
	switch (insn.getOpcode()) {
	case Opcodes.TABLESWITCH:
		TableSwitchInsnNode tsin = (TableSwitchInsnNode) insn;
		if (i < tsin.min || i > tsin.max) {
			return InsnValue.intValue(-1);
		}
		return InsnValue.intValue(i);
	case Opcodes.LOOKUPSWITCH:
		LookupSwitchInsnNode lsin = (LookupSwitchInsnNode) insn;
		for (Object o : lsin.keys) {
			if (o.equals(i)) {
				return InsnValue.intValue(i);
			}
		}
		return InsnValue.intValue(-1);
	}

	return null;
}
 

/**
 * <p>
 * This method finds Switch block in a method and processes it
 * </p>.
 *
 * @param scanStartIndex Start index for the scan
 * @param scanEndIndex End index for the scan
 */
private void instrumentswitchBlock(int scanStartIndex,
		int scanEndIndex) {
	for (scanIndexForswitch = scanStartIndex; scanIndexForswitch <= scanEndIndex; scanIndexForswitch++) {
		AbstractInsnNode currentInsnNode = insnArr[scanIndexForswitch];

		if (currentInsnNode instanceof TableSwitchInsnNode
				&& Opcodes.TABLESWITCH == currentInsnNode.getOpcode()) {
			processTableSwitchBlock((TableSwitchInsnNode) currentInsnNode);
		} else if (currentInsnNode instanceof LookupSwitchInsnNode
				&& Opcodes.LOOKUPSWITCH == currentInsnNode.getOpcode()) {
			processLookupSwitchBlock((LookupSwitchInsnNode) currentInsnNode);
		}

	}
}
 

@Test
public void test_checkLookupSwitch() throws Exception {
    List<BasicBlock> hashCodeBlocks = METHOD_BLOCKS.get("checkLookupSwitch(I)I");
    int[][] expectedHashCodeBlocks = new int[][]{
            {Opcodes.ICONST_5, Opcodes.ISTORE, Opcodes.ILOAD, Opcodes.LOOKUPSWITCH},
            {Opcodes.ICONST_1, Opcodes.ISTORE, Opcodes.GOTO},
            {Opcodes.ICONST_2, Opcodes.ISTORE, Opcodes.GOTO},
            {Opcodes.ICONST_3, Opcodes.ISTORE, Opcodes.GOTO},
            {Opcodes.ICONST_0, Opcodes.ISTORE},
            {Opcodes.ILOAD, Opcodes.IRETURN},
    };
    int[][] expectedSwitchCounts = new int[][]{
        {4},
        {},
        {},
        {},
        {},
        {},
    };
    
    // Verify the shape of the blocks.
    boolean didMatch = compareBlocks(expectedHashCodeBlocks, hashCodeBlocks);
    Assert.assertTrue(didMatch);
    
    // Verify the switch option value.
    didMatch = compareSwitches(expectedSwitchCounts, hashCodeBlocks);
    Assert.assertTrue(didMatch);
}
 

/**
 * Constructs a new {@link LookupSwitchInsnNode}.
 * 
 * @param dflt
 *          beginning of the default handler block.
 * @param keys
 *          the values of the keys.
 * @param labels
 *          beginnings of the handler blocks. <tt>labels[i]</tt> is the
 *          beginning of the handler block for the <tt>keys[i]</tt> key.
 */
public LookupSwitchInsnNode(final LabelNode dflt, final int[] keys, final LabelNode[] labels) {
  super(Opcodes.LOOKUPSWITCH);
  this.dflt = dflt;
  this.keys = new ArrayList<Integer>(keys == null ? 0 : keys.length);
  this.labels = new ArrayList<LabelNode>(labels == null ? 0 : labels.length);
  if (keys != null) {
    for (int i = 0; i < keys.length; ++i) {
      this.keys.add(keys[i]);
    }
  }
  if (labels != null) {
    this.labels.addAll(Arrays.asList(labels));
  }
}
 

@Override
public final void visitLookupSwitchInsn(final Label dflt, final int[] keys, final Label[] labels) {
  AttributesImpl att = new AttributesImpl();
  att.addAttribute("", "dflt", "dflt", "", getLabel(dflt));
  String o = Printer.OPCODES[Opcodes.LOOKUPSWITCH];
  sa.addStart(o, att);
  for (int i = 0; i < labels.length; i++) {
    AttributesImpl att2 = new AttributesImpl();
    att2.addAttribute("", "name", "name", "", getLabel(labels[i]));
    att2.addAttribute("", "key", "key", "", Integer.toString(keys[i]));
    sa.addElement("label", att2);
  }
  sa.addEnd(o);
}
 

public LookupSwitchInsnNode() {
  super(Opcodes.LOOKUPSWITCH);
  keys = new ArrayList<>();
  labels = new ArrayList<>();
}
 

/**
 * Constructs a new {@link LookupSwitchInsnNode}.
 *
 * @param dflt
 *          beginning of the default handler block.
 * @param keys
 *          the values of the keys.
 * @param labels
 *          beginnings of the handler blocks. {@code labels[i]} is the beginning of the handler block for the {@code keys[i]} key.
 */
public LookupSwitchInsnNode(final LabelNode dflt, final int[] keys, final LabelNode[] labels) {
	super(Opcodes.LOOKUPSWITCH);
	this.dflt = dflt;
	this.keys = Util.asArrayList(keys);
	this.labels = Util.asArrayList(labels);
}
 

/**
 * Constructs a new {@link LookupSwitchInsnNode}.
 *
 * @param dflt beginning of the default handler block.
 * @param keys the values of the keys.
 * @param labels beginnings of the handler blocks. {@code labels[i]} is the beginning of the
 *     handler block for the {@code keys[i]} key.
 */
public LookupSwitchInsnNode(final LabelNode dflt, final int[] keys, final LabelNode[] labels) {
  super(Opcodes.LOOKUPSWITCH);
  this.dflt = dflt;
  this.keys = Util.asArrayList(keys);
  this.labels = Util.asArrayList(labels);
}
 

/**
 * Constructs a new {@link LookupSwitchInsnNode}.
 *
 * @param dflt beginning of the default handler block.
 * @param keys the values of the keys.
 * @param labels beginnings of the handler blocks. {@code labels[i]} is the beginning of the
 *     handler block for the {@code keys[i]} key.
 */
public LookupSwitchInsnNode(final LabelNode dflt, final int[] keys, final LabelNode[] labels) {
  super(Opcodes.LOOKUPSWITCH);
  this.dflt = dflt;
  this.keys = Util.asArrayList(keys);
  this.labels = Util.asArrayList(labels);
}
 

/**
 * Constructs a new {@link LookupSwitchInsnNode}.
 *
 * @param dflt beginning of the default handler block.
 * @param keys the values of the keys.
 * @param labels beginnings of the handler blocks. {@code labels[i]} is the beginning of the
 *     handler block for the {@code keys[i]} key.
 */
public LookupSwitchInsnNode(final LabelNode dflt, final int[] keys, final LabelNode[] labels) {
  super(Opcodes.LOOKUPSWITCH);
  this.dflt = dflt;
  this.keys = Util.asArrayList(keys);
  this.labels = Util.asArrayList(labels);
}