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Common Lisp implementation running on the JVM
/*
* JavaObject.java
*
* Copyright (C) 2002-2005 Peter Graves
* $Id$
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* As a special exception, the copyright holders of this library give you
* permission to link this library with independent modules to produce an
* executable, regardless of the license terms of these independent
* modules, and to copy and distribute the resulting executable under
* terms of your choice, provided that you also meet, for each linked
* independent module, the terms and conditions of the license of that
* module. An independent module is a module which is not derived from
* or based on this library. If you modify this library, you may extend
* this exception to your version of the library, but you are not
* obligated to do so. If you do not wish to do so, delete this
* exception statement from your version.
*/
package org.armedbear.lisp;
import static org.armedbear.lisp.Lisp.*;
import java.lang.reflect.Array;
import java.lang.reflect.Field;
import java.math.BigInteger;
import java.util.*;
public final class JavaObject extends LispObject {
final Object obj;
private final Class intendedClass;
public JavaObject(Object obj) {
this.obj = obj;
this.intendedClass =
obj != null ? Java.maybeBoxClass(obj.getClass()) : null;
}
public static final Symbol JAVA_CLASS_JCLASS = PACKAGE_JAVA.intern("JAVA-CLASS-JCLASS");
public static final Symbol JAVA_CLASS = PACKAGE_JAVA.intern("JAVA-CLASS");
public static final Symbol ENSURE_JAVA_CLASS = PACKAGE_JAVA.intern("ENSURE-JAVA-CLASS");
/**
* Constructs a Java Object with the given intended class, used to access
* the object reflectively. If the class represents a primitive type,
* the corresponding wrapper type is used instead.
* @throws ClassCastException if the object is not an instance of the
* intended class.
*/
public JavaObject(Object obj, Class intendedClass) {
if(obj != null && intendedClass == null) {
intendedClass = obj.getClass();
}
if(intendedClass != null) {
intendedClass = Java.maybeBoxClass(intendedClass);
if(!intendedClass.isInstance(obj)) {
if (intendedClass.equals(java.lang.Byte.class)
&& obj instanceof java.lang.Number) {
// Maps any number to two's complement 8bit byte representation
// ??? Is this a reasonable thing?
this.obj = ((java.lang.Number)obj).byteValue();
this.intendedClass = intendedClass;
return;
}
throw new ClassCastException(obj + " can not be cast to " + intendedClass);
}
}
this.obj = obj;
this.intendedClass = intendedClass;
}
@Override
public LispObject typeOf()
{
return Symbol.JAVA_OBJECT;
}
@Override
public LispObject classOf()
{
if(obj == null) {
return BuiltInClass.JAVA_OBJECT;
} else {
return ENSURE_JAVA_CLASS.execute(new JavaObject(obj.getClass()));
}
}
@Override
public LispObject typep(LispObject type) {
if (type == Symbol.JAVA_OBJECT)
return T;
if (type == BuiltInClass.JAVA_OBJECT)
return T;
LispObject cls = NIL;
if(type instanceof Symbol) {
cls = LispClass.findClass(type, false);
}
if(cls == NIL) {
cls = type;
}
if(cls.typep(LispClass.findClass(JAVA_CLASS, false)) != NIL) {
if(obj != null) {
Class c = (Class) JAVA_CLASS_JCLASS.execute(cls).javaInstance();
return c.isAssignableFrom(obj.getClass()) ? T : NIL;
} else {
return T;
}
} else if(cls == BuiltInClass.SEQUENCE) {
//This information is replicated here from java.lisp; it is a very
//specific case, not worth implementing CPL traversal in typep
if(java.util.List.class.isInstance(obj) ||
java.util.Set.class.isInstance(obj)) {
return T;
}
}
return super.typep(type);
}
@Override
public LispObject STRING()
{
return new SimpleString(obj != null? obj.toString(): "null");
}
public final Object getObject()
{
return obj;
}
/** Encapsulates obj, if required.
* If obj is a {@link LispObject}, it's returned as-is.
*
* @param obj Any java object
* @return obj or a new JavaObject encapsulating obj
*/
public final static LispObject getInstance(Object obj) {
if (obj == null)
return new JavaObject(null);
if (obj instanceof LispObject)
return (LispObject)obj;
return new JavaObject(obj);
}
/** Encapsulates obj, if required.
* If obj is a {@link LispObject}, it's returned as-is.
* If not, a java object with the specified intended class is returned.
*
* @param obj Any java object
* @param intendedClass the class that shall be used to access obj
* @return obj or a new JavaObject encapsulating obj
*/
public final static LispObject getInstance(Object obj, Class intendedClass) {
if (obj == null)
return new JavaObject(null);
if (obj instanceof LispObject)
return (LispObject)obj;
return new JavaObject(obj, intendedClass);
}
/** Encapsulates obj, if required.
* If obj is a {@link LispObject}, it's returned as-is.
* If obj is of a type which can be mapped to a lisp type,
* an object of the mapped type is returned, if translated is true.
*
* @param obj
* @param translated
* @return a LispObject representing or encapsulating obj
*/
public final static LispObject getInstance(Object obj, boolean translated) {
return getInstance(obj, translated, obj != null ? obj.getClass() : null);
}
/** Encapsulates obj, if required.
* If obj is a {@link LispObject}, it's returned as-is.
* If obj is of a type which can be mapped to a lisp type,
* an object of the mapped type is returned, if translated is true.
*
* @param obj
* @param translated
* @param intendedClass the class that shall be used to reflectively
* access obj; it is an error for obj not to be
* an instance of this class. This parameter is ignored
* if translated == true and the object can be
* converted to a Lisp object.
* @return a LispObject representing or encapsulating obj
*/
public final static LispObject getInstance(Object obj, boolean translated, Class intendedClass) {
if (! translated)
return getInstance(obj, intendedClass);
if (obj == null) return NIL;
if (obj instanceof LispObject)
return (LispObject)obj;
if (obj instanceof String)
return new SimpleString((String)obj);
if (obj instanceof Number) {
// Number types ordered according to decreasing
// estimated chances of occurrance
if (obj instanceof Integer)
return Fixnum.getInstance(((Integer)obj).intValue());
if (obj instanceof Float)
return new SingleFloat((Float)obj);
if (obj instanceof Double)
return new DoubleFloat((Double)obj);
if (obj instanceof Long)
return LispInteger.getInstance(((Long)obj).longValue());
if (obj instanceof BigInteger)
return Bignum.getInstance((BigInteger)obj);
if (obj instanceof Short)
return Fixnum.getInstance(((Short)obj).shortValue());
if (obj instanceof Byte)
return Fixnum.getInstance(((Byte)obj).byteValue());
// We don't handle BigDecimal: it doesn't map to a Lisp type
}
if (obj instanceof Boolean)
return ((Boolean)obj).booleanValue() ? T : NIL;
if (obj instanceof Character)
return LispCharacter.getInstance((Character)obj);
if (obj instanceof Object[]) {
Object[] array = (Object[]) obj;
SimpleVector v = new SimpleVector(array.length);
for (int i = array.length; i-- > 0;)
v.aset(i, JavaObject.getInstance(array[i], translated));
return v;
}
// TODO
// We might want to handle:
// - streams
// - others?
return new JavaObject(obj, intendedClass);
}
@Override
public Object javaInstance() {
return obj;
}
@Override
public Object javaInstance(Class c) {
if(obj == null) {
if(c.isPrimitive()) {
throw new NullPointerException("Cannot assign null to " + c);
}
return obj;
} else {
c = Java.maybeBoxClass(c);
if (c.isAssignableFrom(intendedClass) || c.isInstance(obj)) {
// XXX In the case that c.isInstance(obj) should we then
// "fix" the intendedClass field with the (presumably)
// narrower type of 'obj'?
// ME 20100323: I decided not to because a) we don't
// know the "proper" class to narrow to (i.e. maybe
// there's something "narrower" and b) I'm not sure how
// primitive types relate to their boxed
// representations.
return obj;
} else {
return error(new TypeError(intendedClass.getName() + " is not assignable to " + c.getName()));
}
}
}
/** Returns the encapsulated Java object for
* interoperability with wait, notify, synchronized, etc.
*
* @return The encapsulated object
*/
@Override
public Object lockableInstance() {
return obj;
}
public Class getIntendedClass() {
return intendedClass;
}
public static final Object getObject(LispObject o)
{
if (o instanceof JavaObject)
return ((JavaObject)o).obj;
return // Not reached.
type_error(o, Symbol.JAVA_OBJECT);
}
@Override
public final boolean equal(LispObject other)
{
if (this == other)
return true;
if (other instanceof JavaObject)
return (obj == ((JavaObject)other).obj);
return false;
}
@Override
public final boolean equalp(LispObject other)
{
return equal(other);
}
@Override
public int sxhash()
{
return obj == null ? 0 : (obj.hashCode() & 0x7ffffff);
}
public static LispObject JAVA_OBJECT_TO_STRING_LENGTH
= LispInteger.getInstance(32);
public static final Symbol _JAVA_OBJECT_TO_STRING_LENGTH
= exportSpecial("*JAVA-OBJECT-TO-STRING-LENGTH*",
PACKAGE_JAVA, JAVA_OBJECT_TO_STRING_LENGTH);
static {
String doc = "Length to truncate toString() PRINT-OBJECT output for an otherwise "
+ "unspecialized JAVA-OBJECT. Can be set to NIL to indicate no limit.";
_JAVA_OBJECT_TO_STRING_LENGTH
.setDocumentation(Symbol.VARIABLE, new SimpleString(doc));
}
@Override
public String printObject()
{
if (obj instanceof ControlTransfer)
return obj.toString();
final String s;
if (obj != null) {
Class c = obj.getClass();
StringBuilder sb
= new StringBuilder(c.isArray() ? "jarray" : c.getName());
sb.append(' ');
try {
String ts = obj.toString();
int length = -1;
LispObject stringLength = _JAVA_OBJECT_TO_STRING_LENGTH.symbolValueNoThrow();
if (stringLength instanceof Fixnum) {
length = Fixnum.getValue(stringLength);
}
if (length < 0) {
sb.append(ts);
} else if (ts.length() > length) {
// use '....' to not confuse user with PPRINT conventions
sb.append(ts.substring(0, length)).append("....");
} else {
sb.append(ts);
}
s = sb.toString();
} catch (Exception e) {
return serror(new JavaException(e));
}
} else {
s = "null";
}
return unreadableString(s);
}
@Override
public LispObject getDescription() {
return new SimpleString(describeJavaObject(this));
}
@Override
public LispObject getParts() {
if(obj != null) {
LispObject parts = NIL;
parts = parts.push(new Cons("Java class",
new JavaObject(obj.getClass())));
if (intendedClass != null) {
parts = parts.push(new Cons("intendedClass", new SimpleString(intendedClass.getCanonicalName())));
}
if (obj.getClass().isArray()) {
int length = Array.getLength(obj);
for (int i = 0; i < length; i++) {
parts = parts
.push(new Cons(new SimpleString(i),
JavaObject.getInstance(Array.get(obj, i))));
}
} else {
parts = Symbol.NCONC.execute(parts, getInspectedFields());
}
if (obj instanceof java.lang.Class) {
Class o = (java.lang.Class)obj;
try {
Class[] classes = o.getClasses();
LispObject classesList = NIL;
for (int i = 0; i < classes.length; i++) {
classesList = classesList.push(JavaObject.getInstance(classes[i]));
}
if (!classesList.equals(NIL)) {
parts = parts
.push(new Cons("Member classes", classesList.nreverse()));
}
} catch (SecurityException e) {
Debug.trace(e);
}
Class[] interfaces = o.getInterfaces();
LispObject interfacesList = NIL;
for (int i = 0; i < interfaces.length; i++) {
interfacesList = interfacesList.push(JavaObject.getInstance(interfaces[i]));
}
if (!interfacesList.equals(NIL)) {
parts = parts
.push(new Cons("Interfaces", interfacesList.nreverse()));
}
LispObject superclassList = NIL;
Class superclass = o.getSuperclass();
while (superclass != null) {
superclassList = superclassList.push(JavaObject.getInstance(superclass));
superclass = superclass.getSuperclass();
}
if (!superclassList.equals(NIL)) {
parts = parts
.push(new Cons("Superclasses", superclassList.nreverse()));
}
}
return parts.nreverse();
} else {
return NIL;
}
}
private LispObject getInspectedFields()
{
final LispObject[] acc = new LispObject[] { NIL };
doClassHierarchy(obj.getClass(), new Function() {
@Override
public LispObject execute(LispObject arg)
{
//No possibility of type error - we're mapping this function
//over a list of classes
Class c = (Class) arg.javaInstance();
for(Field f : c.getDeclaredFields()) {
LispObject value = NIL;
try {
if(!f.isAccessible()) {
f.setAccessible(true);
}
value = JavaObject.getInstance(f.get(obj));
} catch(Exception e) {}
acc[0] = acc[0].push(new Cons(f.getName(), value));
}
return acc[0];
}
});
return acc[0].nreverse();
}
/**
* Executes a function repeatedly over the minimal subtree of the
* Java class hierarchy which contains every class in .
*/
private static void doClassHierarchy(Collection> classes,
LispObject callback,
Set> visited)
{
Collection> newClasses = new LinkedList>();
for(Class clss : classes) {
if(clss == null) {
continue;
}
if(!visited.contains(clss)) {
callback.execute(JavaObject.getInstance(clss, true));
visited.add(clss);
}
if(!visited.contains(clss.getSuperclass())) {
newClasses.add(clss.getSuperclass());
}
for(Class iface : clss.getInterfaces()) {
if (!visited.contains(iface)) {
newClasses.add(iface);
}
}
}
if(!newClasses.isEmpty()) {
doClassHierarchy(newClasses, callback, visited);
}
}
/**
* Executes a function recursively over and its superclasses and
* interfaces.
*/
public static void doClassHierarchy(Class clss, LispObject callback)
{
if (clss != null) {
Set> visited = new HashSet>();
Collection> classes = new ArrayList>(1);
classes.add(clss);
doClassHierarchy(classes, callback, visited);
}
}
public static LispObject mapcarClassHierarchy(Class clss,
final LispObject fn)
{
final LispObject[] acc = new LispObject[] { NIL };
doClassHierarchy(clss, new Function() {
@Override
public LispObject execute(LispObject arg)
{
acc[0] = acc[0].push(fn.execute(arg));
return acc[0];
}
});
return acc[0].nreverse();
}
public static String describeJavaObject(final JavaObject javaObject)
{
final Object obj = javaObject.getObject();
final StringBuilder sb =
new StringBuilder(javaObject.princToString());
sb.append(" is an object of type ");
sb.append(Symbol.JAVA_OBJECT.princToString());
sb.append(".");
sb.append(System.getProperty("line.separator"));
sb.append("The wrapped Java object is ");
if (obj == null) {
sb.append("null.");
} else {
sb.append("an ");
final Class c = obj.getClass();
String className = c.getName();
if (c.isArray()) {
sb.append("array of ");
if (className.startsWith("[L") && className.endsWith(";")) {
className = className.substring(1, className.length() - 1);
sb.append(className);
sb.append(" objects");
} else if (className.startsWith("[") && className.length() > 1) {
char descriptor = className.charAt(1);
final String type;
switch (descriptor) {
case 'B': type = "bytes"; break;
case 'C': type = "chars"; break;
case 'D': type = "doubles"; break;
case 'F': type = "floats"; break;
case 'I': type = "ints"; break;
case 'J': type = "longs"; break;
case 'S': type = "shorts"; break;
case 'Z': type = "booleans"; break;
default:
type = "unknown type";
}
sb.append(type);
}
sb.append(" with ");
final int length = java.lang.reflect.Array.getLength(obj);
sb.append(length);
sb.append(" element");
if (length != 1)
sb.append('s');
sb.append('.');
} else {
sb.append("instance of ");
sb.append(className);
sb.append(':');
sb.append(System.getProperty("line.separator"));
sb.append(" \"");
sb.append(obj.toString());
sb.append('"');
}
}
return sb.toString();
}
// ### describe-java-object
private static final Primitive DESCRIBE_JAVA_OBJECT =
new Primitive("describe-java-object", PACKAGE_JAVA, true)
{
@Override
public LispObject execute(LispObject first, LispObject second)
{
if (!(first instanceof JavaObject))
return type_error(first, Symbol.JAVA_OBJECT);
final Stream stream = checkStream(second);
final JavaObject javaObject = (JavaObject) first;
stream._writeString(describeJavaObject(javaObject));
return LispThread.currentThread().nothing();
}
};
//JAVA-CLASS support
//There is no point for this Map to be weak since values keep a reference to the corresponding
//key (the Java class). This should not be a problem since Java classes are limited in number -
//if they grew indefinitely, the JVM itself would crash.
private static final Map, LispObject> javaClassMap = new HashMap, LispObject>();
public static LispObject registerJavaClass(Class javaClass, LispObject classMetaObject) {
synchronized (javaClassMap) {
javaClassMap.put(javaClass, classMetaObject);
return classMetaObject;
}
}
public static LispObject findJavaClass(Class javaClass) {
synchronized (javaClassMap) {
LispObject c = javaClassMap.get(javaClass);
if (c != null) {
return c;
} else {
return NIL;
}
}
}
private static final Primitive _FIND_JAVA_CLASS = new Primitive("%find-java-class", PACKAGE_JAVA, false, "class-name-or-class") {
public LispObject execute(LispObject arg) {
try {
if(arg instanceof AbstractString) {
return findJavaClass(Class.forName((String) arg.getStringValue()));
} else {
return findJavaClass((Class) arg.javaInstance());
}
} catch (ClassNotFoundException e) {
return error(new LispError("Cannot find Java class " + arg.getStringValue()));
}
}
};
private static final Primitive _REGISTER_JAVA_CLASS = new Primitive("%register-java-class", PACKAGE_JAVA, false, "jclass class-metaobject") {
public LispObject execute(LispObject jclass, LispObject classMetaObject) {
return registerJavaClass((Class) jclass.javaInstance(), classMetaObject);
}
};
// ### +null+
public final static Symbol NULL
= Lisp.exportConstant("+NULL+", PACKAGE_JAVA, new JavaObject(null));
static {
String doc = "The JVM null object reference.";
NULL.setDocumentation(Symbol.VARIABLE, new SimpleString(doc));
}
// ### +true+
public final static Symbol TRUE
= Lisp.exportConstant("+TRUE+", PACKAGE_JAVA, new JavaObject(true));
static {
String doc = "The JVM primitive value for boolean true.";
TRUE.setDocumentation(Symbol.VARIABLE, new SimpleString(doc));
}
// ### +false+
public final static Symbol FALSE
= Lisp.exportConstant("+FALSE+", PACKAGE_JAVA, new JavaObject(false));
static {
String doc = "The JVM primitive value for boolean false.";
FALSE.setDocumentation(Symbol.VARIABLE, new SimpleString(doc));
}
}