+ * A visit* method is called when a constant pool entry is parsed.
+ * The first argument is always the constant pool index.
+ * The second argument is always the constant pool tag,
+ * even for methods like {@link #visitUTF8(int, byte, String)} which only apply to one tag.
+ * String arguments refer to Utf8 or NameAndType entries declared elsewhere,
+ * and are always accompanied by the indexes of those entries.
+ *
+ * The order of the calls to the visit* methods is not necessarily related
+ * to the order of the entries in the constant pool.
+ * If one entry has a reference to another entry, the latter (lower-level)
+ * entry will be visited first.
+ *
+ * The following table shows the relation between constant pool entry
+ * types and the corresponding visit* methods:
+ *
+ *
+ * | Tag(s) | Method |
|---|
+ *
+ * | {@link #CONSTANT_Utf8} |
+ * {@link #visitUTF8(int, byte, String)} |
+ *
+ * | {@link #CONSTANT_Integer}, {@link #CONSTANT_Float},
+ * {@link #CONSTANT_Long}, {@link #CONSTANT_Double} |
+ * {@link #visitConstantValue(int, byte, Object)} |
+ *
+ * | {@link #CONSTANT_String}, {@link #CONSTANT_Class} |
+ * {@link #visitConstantString(int, byte, String, int)} |
+ *
+ * | {@link #CONSTANT_NameAndType} |
+ * {@link #visitDescriptor(int, byte, String, String, int, int)} |
+ *
+ * | {@link #CONSTANT_Fieldref},
+ * {@link #CONSTANT_Methodref},
+ * {@link #CONSTANT_InterfaceMethodref} |
+ * {@link #visitMemberRef(int, byte, String, String, String, int, int)} |
+ *
+ *
+ *
+ * @see ConstantPoolPatch
+ * @author Remi Forax
+ * @author jrose
+ */
+public class ConstantPoolVisitor {
+ /** Called each time an UTF8 constant pool entry is found.
+ * @param index the constant pool index
+ * @param tag always {@link #CONSTANT_Utf8}
+ * @param utf8 string encoded in modified UTF-8 format passed as a {@code String}
+ *
+ * @see ConstantPoolPatch#putUTF8(int, String)
+ */
+ public void visitUTF8(int index, byte tag, String utf8) {
+ // do nothing
+ }
+
+ /** Called for each constant pool entry that encodes an integer,
+ * a float, a long, or a double.
+ * Constant strings and classes are not managed by this method but
+ * by {@link #visitConstantString(int, byte, String, int)}.
+ *
+ * @param index the constant pool index
+ * @param tag one of {@link #CONSTANT_Integer},
+ * {@link #CONSTANT_Float},
+ * {@link #CONSTANT_Long},
+ * or {@link #CONSTANT_Double}
+ * @param value encoded value
+ *
+ * @see ConstantPoolPatch#putConstantValue(int, Object)
+ */
+ public void visitConstantValue(int index, byte tag, Object value) {
+ // do nothing
+ }
+
+ /** Called for each constant pool entry that encodes a string or a class.
+ * @param index the constant pool index
+ * @param tag one of {@link #CONSTANT_String},
+ * {@link #CONSTANT_Class},
+ * @param name string body or class name (using dot separator)
+ * @param nameIndex the index of the Utf8 string for the name
+ *
+ * @see ConstantPoolPatch#putConstantValue(int, byte, Object)
+ */
+ public void visitConstantString(int index, byte tag,
+ String name, int nameIndex) {
+ // do nothing
+ }
+
+ /** Called for each constant pool entry that encodes a name and type.
+ * @param index the constant pool index
+ * @param tag always {@link #CONSTANT_NameAndType}
+ * @param memberName a field or method name
+ * @param signature the member signature
+ * @param memberNameIndex index of the Utf8 string for the member name
+ * @param signatureIndex index of the Utf8 string for the signature
+ *
+ * @see ConstantPoolPatch#putDescriptor(int, String, String)
+ */
+ public void visitDescriptor(int index, byte tag,
+ String memberName, String signature,
+ int memberNameIndex, int signatureIndex) {
+ // do nothing
+ }
+
+ /** Called for each constant pool entry that encodes a field or method.
+ * @param index the constant pool index
+ * @param tag one of {@link #CONSTANT_Fieldref},
+ * or {@link #CONSTANT_Methodref},
+ * or {@link #CONSTANT_InterfaceMethodref}
+ * @param className the class name (using dot separator)
+ * @param memberName name of the field or method
+ * @param signature the field or method signature
+ * @param classNameIndex index of the Utf8 string for the class name
+ * @param descriptorIndex index of the NameAndType descriptor constant
+ *
+ * @see ConstantPoolPatch#putMemberRef(int, byte, String, String, String)
+ */
+ public void visitMemberRef(int index, byte tag,
+ String className, String memberName, String signature,
+ int classNameIndex, int descriptorIndex) {
+ // do nothing
+ }
+
+ public static final byte
+ CONSTANT_None = 0,
+ CONSTANT_Utf8 = 1,
+ //CONSTANT_Unicode = 2, /* unused */
+ CONSTANT_Integer = 3,
+ CONSTANT_Float = 4,
+ CONSTANT_Long = 5,
+ CONSTANT_Double = 6,
+ CONSTANT_Class = 7,
+ CONSTANT_String = 8,
+ CONSTANT_Fieldref = 9,
+ CONSTANT_Methodref = 10,
+ CONSTANT_InterfaceMethodref = 11,
+ CONSTANT_NameAndType = 12;
+
+ private static String[] TAG_NAMES = {
+ "Empty",
+ "Utf8",
+ null, //"Unicode",
+ "Integer",
+ "Float",
+ "Long",
+ "Double",
+ "Class",
+ "String",
+ "Fieldref",
+ "Methodref",
+ "InterfaceMethodref",
+ "NameAndType"
+ };
+
+ public static String tagName(byte tag) {
+ String name = null;
+ if ((tag & 0xFF) < TAG_NAMES.length)
+ name = TAG_NAMES[tag];
+ if (name == null)
+ name = "Unknown#"+(tag&0xFF);
+ return name;
+ }
+}