com.ibm.wala.util.strings

Class Atom

java.lang.Object

com.ibm.wala.util.strings.Atom

All Implemented Interfaces:

java.io.Serializable

public final class Atom
extends java.lang.Object
implements java.io.Serializable

An utf8-encoded byte string.

Atom's are interned (canonicalized) so they may be compared for equality using the "==" operator.

Atoms are used to represent names, descriptors, and string literals appearing in a class's constant pool.

See Also:

Serialized Form

Method Summary

Modifier and Type	Method and Description
Atom	arrayDescriptorFromElementDescriptor() Return array descriptor corresponding to "this" array-element descriptor.
static Atom	concat(Atom ma, Atom mb)
static Atom	concat(byte c, ImmutableByteArray b)
boolean	contains(byte b)
boolean	equals(java.lang.Object obj)
static Atom	findOrCreate(byte[] bytes)
static Atom	findOrCreate(byte[] utf8, int off, int len) create an Atom from utf8[off] of length len
static Atom	findOrCreate(ImmutableByteArray b)
static Atom	findOrCreate(ImmutableByteArray b, int start, int length)
static Atom	findOrCreateAsciiAtom(java.lang.String str) Find or create an atom.
static Atom	findOrCreateUnicodeAtom(java.lang.String str) Find or create an atom.
static Atom	findOrCreateUtf8Atom(byte[] utf8) Find or create an atom.
byte	getVal(int i)
byte[]	getValArray() return an array of bytes representing the utf8 characters in this
int	hashCode()
boolean	isArrayDescriptor() Is "this" atom an array descriptor?
static boolean	isArrayDescriptor(ImmutableByteArray b)
boolean	isClassDescriptor() Is "this" atom a class descriptor?
boolean	isMethodDescriptor() Is "this" atom a method descriptor?
boolean	isReservedMemberName() Is "this" atom a reserved member name? Note: Sun has reserved all member names starting with '<' for future use.
Atom	left(int count) New Atom containing first count bytes
int	length()
int	parseForArrayDimensionality() Parse "this" array descriptor to obtain number of dimensions in corresponding array type.
Atom	parseForArrayElementDescriptor() Parse "this" array descriptor to obtain descriptor for array's element type.
Atom	parseForInnermostArrayElementDescriptor() Return the innermost element type reference for an array
Atom	right(int count) New Atom containing last count bytes
int	rIndex(byte b)
boolean	startsWith(Atom start)
java.lang.String	toString() Return printable representation of "this" atom.
java.lang.String	toUnicodeString() Return printable representation of "this" atom.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

findOrCreateUnicodeAtom

public static Atom findOrCreateUnicodeAtom(java.lang.String str)

Find or create an atom.

Parameters:

str - atom value, as string literal whose characters are unicode

Returns:

atom

findOrCreateAsciiAtom

public static Atom findOrCreateAsciiAtom(java.lang.String str)

Find or create an atom.

Parameters:

str - atom value, as string literal whose characters are from ascii subset of unicode (not including null)

Returns:

atom

Throws:

java.lang.IllegalArgumentException - if str is null

findOrCreateUtf8Atom

public static Atom findOrCreateUtf8Atom(byte[] utf8)

Find or create an atom.

Parameters:

utf8 - atom value, as utf8 encoded bytes

Returns:

atom

Throws:

java.lang.IllegalArgumentException - if utf8 is null

findOrCreate

public static Atom findOrCreate(byte[] utf8,
                                int off,
                                int len)
                         throws java.lang.IllegalArgumentException,
                                java.lang.IllegalArgumentException,
                                java.lang.IllegalArgumentException

create an Atom from utf8[off] of length len

Throws:

java.lang.IllegalArgumentException - if utf8.length <= off

findOrCreate

public static Atom findOrCreate(byte[] bytes)

findOrCreate

public static Atom findOrCreate(ImmutableByteArray b)

findOrCreate

public static Atom findOrCreate(ImmutableByteArray b,
                                int start,
                                int length)

toString

public final java.lang.String toString()

Return printable representation of "this" atom. Does not correctly handle UTF8 translation.

Overrides:

toString in class java.lang.Object

toUnicodeString

public final java.lang.String toUnicodeString()
                                       throws java.io.UTFDataFormatException

Return printable representation of "this" atom.

Throws:

java.io.UTFDataFormatException

left

public final Atom left(int count)

New Atom containing first count bytes

right

public final Atom right(int count)

New Atom containing last count bytes

startsWith

public final boolean startsWith(Atom start)

arrayDescriptorFromElementDescriptor

public final Atom arrayDescriptorFromElementDescriptor()

Return array descriptor corresponding to "this" array-element descriptor. this: array-element descriptor - something like "I" or "Ljava/lang/Object;"

Returns:

array descriptor - something like "[I" or "[Ljava/lang/Object;"

isReservedMemberName

public final boolean isReservedMemberName()

Is "this" atom a reserved member name? Note: Sun has reserved all member names starting with '<' for future use. At present, only <init> and <clinit> are used.

isClassDescriptor

public final boolean isClassDescriptor()

Is "this" atom a class descriptor?

isArrayDescriptor

public final boolean isArrayDescriptor()

Is "this" atom an array descriptor?

isMethodDescriptor

public final boolean isMethodDescriptor()
                                 throws java.lang.IllegalArgumentException

Is "this" atom a method descriptor?

Throws:

java.lang.IllegalArgumentException

length

public final int length()

parseForArrayElementDescriptor

public final Atom parseForArrayElementDescriptor()
                                          throws java.lang.IllegalArgumentException

Parse "this" array descriptor to obtain descriptor for array's element type. this: array descriptor - something like "[I"

Returns:

array element descriptor - something like "I"

Throws:

java.lang.IllegalArgumentException

parseForArrayDimensionality

public final int parseForArrayDimensionality()
                                      throws java.lang.IllegalArgumentException

Parse "this" array descriptor to obtain number of dimensions in corresponding array type. this: descriptor - something like "[Ljava/lang/String;" or "[[I"

Returns:

dimensionality - something like "1" or "2"

Throws:

java.lang.IllegalStateException - if this Atom does not represent an array

java.lang.IllegalArgumentException

parseForInnermostArrayElementDescriptor

public final Atom parseForInnermostArrayElementDescriptor()
                                                   throws java.lang.IllegalArgumentException

Return the innermost element type reference for an array

Throws:

java.lang.IllegalStateException - if this Atom does not represent an array descriptor

java.lang.IllegalArgumentException

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

equals

public boolean equals(java.lang.Object obj)

Overrides:

equals in class java.lang.Object

getValArray

public byte[] getValArray()

return an array of bytes representing the utf8 characters in this

getVal

public byte getVal(int i)
            throws java.lang.IllegalArgumentException

Throws:

java.lang.IllegalArgumentException

contains

public boolean contains(byte b)

Returns:

true iff this atom contains the specified byte

rIndex

public int rIndex(byte b)

concat

public static Atom concat(byte c,
                          ImmutableByteArray b)

concat

public static Atom concat(Atom ma,
                          Atom mb)

isArrayDescriptor

public static boolean isArrayDescriptor(ImmutableByteArray b)