jscover.mozilla.javascript.NativeJavaMethod Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of rhino Show documentation
Show all versions of rhino Show documentation
Rhino is an open-source implementation of JavaScript written entirely in
Java. It is typically embedded into Java applications to provide
scripting to end users.
/* -*- Mode: java; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
package jscover.mozilla.javascript;
import java.lang.reflect.*;
import java.util.Arrays;
import java.util.concurrent.CopyOnWriteArrayList;
/**
* This class reflects Java methods into the JavaScript environment and
* handles overloading of methods.
*
* @author Mike Shaver
* @see NativeJavaArray
* @see NativeJavaPackage
* @see NativeJavaClass
*/
public class NativeJavaMethod extends BaseFunction
{
static final long serialVersionUID = -3440381785576412928L;
NativeJavaMethod(MemberBox[] methods)
{
this.functionName = methods[0].getName();
this.methods = methods;
}
NativeJavaMethod(MemberBox[] methods, String name)
{
this.functionName = name;
this.methods = methods;
}
NativeJavaMethod(MemberBox method, String name)
{
this.functionName = name;
this.methods = new MemberBox[] { method };
}
public NativeJavaMethod(Method method, String name)
{
this(new MemberBox(method), name);
}
@Override
public String getFunctionName()
{
return functionName;
}
static String scriptSignature(Object[] values)
{
StringBuffer sig = new StringBuffer();
for (int i = 0; i != values.length; ++i) {
Object value = values[i];
String s;
if (value == null) {
s = "null";
} else if (value instanceof Boolean) {
s = "boolean";
} else if (value instanceof String) {
s = "string";
} else if (value instanceof Number) {
s = "number";
} else if (value instanceof Scriptable) {
if (value instanceof Undefined) {
s = "undefined";
} else if (value instanceof Wrapper) {
Object wrapped = ((Wrapper)value).unwrap();
s = wrapped.getClass().getName();
} else if (value instanceof Function) {
s = "function";
} else {
s = "object";
}
} else {
s = JavaMembers.javaSignature(value.getClass());
}
if (i != 0) {
sig.append(',');
}
sig.append(s);
}
return sig.toString();
}
@Override
String decompile(int indent, int flags)
{
StringBuffer sb = new StringBuffer();
boolean justbody = (0 != (flags & Decompiler.ONLY_BODY_FLAG));
if (!justbody) {
sb.append("function ");
sb.append(getFunctionName());
sb.append("() {");
}
sb.append("/*\n");
sb.append(toString());
sb.append(justbody ? "*/\n" : "*/}\n");
return sb.toString();
}
@Override
public String toString()
{
StringBuffer sb = new StringBuffer();
for (int i = 0, N = methods.length; i != N; ++i) {
// Check member type, we also use this for overloaded constructors
if (methods[i].isMethod()) {
Method method = methods[i].method();
sb.append(JavaMembers.javaSignature(method.getReturnType()));
sb.append(' ');
sb.append(method.getName());
} else {
sb.append(methods[i].getName());
}
sb.append(JavaMembers.liveConnectSignature(methods[i].argTypes));
sb.append('\n');
}
return sb.toString();
}
@Override
public Object call(Context cx, Scriptable scope, Scriptable thisObj,
Object[] args)
{
// Find a method that matches the types given.
if (methods.length == 0) {
throw new RuntimeException("No methods defined for call");
}
int index = findCachedFunction(cx, args);
if (index < 0) {
Class c = methods[0].method().getDeclaringClass();
String sig = c.getName() + '.' + getFunctionName() + '(' +
scriptSignature(args) + ')';
throw Context.reportRuntimeError1("msg.java.no_such_method", sig);
}
MemberBox meth = methods[index];
Class[] argTypes = meth.argTypes;
if (meth.vararg) {
// marshall the explicit parameters
Object[] newArgs = new Object[argTypes.length];
for (int i = 0; i < argTypes.length-1; i++) {
newArgs[i] = Context.jsToJava(args[i], argTypes[i]);
}
Object varArgs;
// Handle special situation where a single variable parameter
// is given and it is a Java or ECMA array or is null.
if (args.length == argTypes.length &&
(args[args.length-1] == null ||
args[args.length-1] instanceof NativeArray ||
args[args.length-1] instanceof NativeJavaArray))
{
// convert the ECMA array into a native array
varArgs = Context.jsToJava(args[args.length-1],
argTypes[argTypes.length - 1]);
} else {
// marshall the variable parameters
Class componentType = argTypes[argTypes.length - 1].
getComponentType();
varArgs = Array.newInstance(componentType,
args.length - argTypes.length + 1);
for (int i = 0; i < Array.getLength(varArgs); i++) {
Object value = Context.jsToJava(args[argTypes.length-1 + i],
componentType);
Array.set(varArgs, i, value);
}
}
// add varargs
newArgs[argTypes.length-1] = varArgs;
// replace the original args with the new one
args = newArgs;
} else {
// First, we marshall the args.
Object[] origArgs = args;
for (int i = 0; i < args.length; i++) {
Object arg = args[i];
Object coerced = Context.jsToJava(arg, argTypes[i]);
if (coerced != arg) {
if (origArgs == args) {
args = args.clone();
}
args[i] = coerced;
}
}
}
Object javaObject;
if (meth.isStatic()) {
javaObject = null; // don't need an object
} else {
Scriptable o = thisObj;
Class c = meth.getDeclaringClass();
for (;;) {
if (o == null) {
throw Context.reportRuntimeError3(
"msg.nonjava.method", getFunctionName(),
ScriptRuntime.toString(thisObj), c.getName());
}
if (o instanceof Wrapper) {
javaObject = ((Wrapper)o).unwrap();
if (c.isInstance(javaObject)) {
break;
}
}
o = o.getPrototype();
}
}
if (debug) {
printDebug("Calling ", meth, args);
}
Object retval = meth.invoke(javaObject, args);
Class staticType = meth.method().getReturnType();
if (debug) {
Class actualType = (retval == null) ? null
: retval.getClass();
System.err.println(" ----- Returned " + retval +
" actual = " + actualType +
" expect = " + staticType);
}
Object wrapped = cx.getWrapFactory().wrap(cx, scope,
retval, staticType);
if (debug) {
Class actualType = (wrapped == null) ? null
: wrapped.getClass();
System.err.println(" ----- Wrapped as " + wrapped +
" class = " + actualType);
}
if (wrapped == null && staticType == Void.TYPE) {
wrapped = Undefined.instance;
}
return wrapped;
}
int findCachedFunction(Context cx, Object[] args) {
if (methods.length > 1) {
if (overloadCache != null) {
for (ResolvedOverload ovl : overloadCache) {
if (ovl.matches(args)) {
return ovl.index;
}
}
} else {
overloadCache = new CopyOnWriteArrayList();
}
int index = findFunction(cx, methods, args);
// As a sanity measure, don't let the lookup cache grow longer
// than twice the number of overloaded methods
if (overloadCache.size() < methods.length * 2) {
synchronized (overloadCache) {
ResolvedOverload ovl = new ResolvedOverload(args, index);
if (!overloadCache.contains(ovl)) {
overloadCache.add(0, ovl);
}
}
}
return index;
}
return findFunction(cx, methods, args);
}
/**
* Find the index of the correct function to call given the set of methods
* or constructors and the arguments.
* If no function can be found to call, return -1.
*/
static int findFunction(Context cx,
MemberBox[] methodsOrCtors, Object[] args)
{
if (methodsOrCtors.length == 0) {
return -1;
} else if (methodsOrCtors.length == 1) {
MemberBox member = methodsOrCtors[0];
Class[] argTypes = member.argTypes;
int alength = argTypes.length;
if (member.vararg) {
alength--;
if ( alength > args.length) {
return -1;
}
} else {
if (alength != args.length) {
return -1;
}
}
for (int j = 0; j != alength; ++j) {
if (!NativeJavaObject.canConvert(args[j], argTypes[j])) {
if (debug) printDebug("Rejecting (args can't convert) ",
member, args);
return -1;
}
}
if (debug) printDebug("Found ", member, args);
return 0;
}
int firstBestFit = -1;
int[] extraBestFits = null;
int extraBestFitsCount = 0;
search:
for (int i = 0; i < methodsOrCtors.length; i++) {
MemberBox member = methodsOrCtors[i];
Class[] argTypes = member.argTypes;
int alength = argTypes.length;
if (member.vararg) {
alength--;
if ( alength > args.length) {
continue search;
}
} else {
if (alength != args.length) {
continue search;
}
}
for (int j = 0; j < alength; j++) {
if (!NativeJavaObject.canConvert(args[j], argTypes[j])) {
if (debug) printDebug("Rejecting (args can't convert) ",
member, args);
continue search;
}
}
if (firstBestFit < 0) {
if (debug) printDebug("Found first applicable ", member, args);
firstBestFit = i;
} else {
// Compare with all currently fit methods.
// The loop starts from -1 denoting firstBestFit and proceed
// until extraBestFitsCount to avoid extraBestFits allocation
// in the most common case of no ambiguity
int betterCount = 0; // number of times member was prefered over
// best fits
int worseCount = 0; // number of times best fits were prefered
// over member
for (int j = -1; j != extraBestFitsCount; ++j) {
int bestFitIndex;
if (j == -1) {
bestFitIndex = firstBestFit;
} else {
bestFitIndex = extraBestFits[j];
}
MemberBox bestFit = methodsOrCtors[bestFitIndex];
if (cx.hasFeature(Context.FEATURE_ENHANCED_JAVA_ACCESS) &&
(bestFit.member().getModifiers() & Modifier.PUBLIC) !=
(member.member().getModifiers() & Modifier.PUBLIC))
{
// When FEATURE_ENHANCED_JAVA_ACCESS gives us access
// to non-public members, continue to prefer public
// methods in overloading
if ((bestFit.member().getModifiers() & Modifier.PUBLIC) == 0)
++betterCount;
else
++worseCount;
} else {
int preference = preferSignature(args, argTypes,
member.vararg,
bestFit.argTypes,
bestFit.vararg );
if (preference == PREFERENCE_AMBIGUOUS) {
break;
} else if (preference == PREFERENCE_FIRST_ARG) {
++betterCount;
} else if (preference == PREFERENCE_SECOND_ARG) {
++worseCount;
} else {
if (preference != PREFERENCE_EQUAL) Kit.codeBug();
// This should not happen in theory
// but on some JVMs, Class.getMethods will return all
// static methods of the class hierarchy, even if
// a derived class's parameters match exactly.
// We want to call the derived class's method.
if (bestFit.isStatic() &&
bestFit.getDeclaringClass().isAssignableFrom(
member.getDeclaringClass()))
{
// On some JVMs, Class.getMethods will return all
// static methods of the class hierarchy, even if
// a derived class's parameters match exactly.
// We want to call the derived class's method.
if (debug) printDebug(
"Substituting (overridden static)",
member, args);
if (j == -1) {
firstBestFit = i;
} else {
extraBestFits[j] = i;
}
} else {
if (debug) printDebug(
"Ignoring same signature member ",
member, args);
}
continue search;
}
}
}
if (betterCount == 1 + extraBestFitsCount) {
// member was prefered over all best fits
if (debug) printDebug(
"New first applicable ", member, args);
firstBestFit = i;
extraBestFitsCount = 0;
} else if (worseCount == 1 + extraBestFitsCount) {
// all best fits were prefered over member, ignore it
if (debug) printDebug(
"Rejecting (all current bests better) ", member, args);
} else {
// some ambiguity was present, add member to best fit set
if (debug) printDebug(
"Added to best fit set ", member, args);
if (extraBestFits == null) {
// Allocate maximum possible array
extraBestFits = new int[methodsOrCtors.length - 1];
}
extraBestFits[extraBestFitsCount] = i;
++extraBestFitsCount;
}
}
}
if (firstBestFit < 0) {
// Nothing was found
return -1;
} else if (extraBestFitsCount == 0) {
// single best fit
return firstBestFit;
}
// report remaining ambiguity
StringBuffer buf = new StringBuffer();
for (int j = -1; j != extraBestFitsCount; ++j) {
int bestFitIndex;
if (j == -1) {
bestFitIndex = firstBestFit;
} else {
bestFitIndex = extraBestFits[j];
}
buf.append("\n ");
buf.append(methodsOrCtors[bestFitIndex].toJavaDeclaration());
}
MemberBox firstFitMember = methodsOrCtors[firstBestFit];
String memberName = firstFitMember.getName();
String memberClass = firstFitMember.getDeclaringClass().getName();
if (methodsOrCtors[0].isCtor()) {
throw Context.reportRuntimeError3(
"msg.constructor.ambiguous",
memberName, scriptSignature(args), buf.toString());
} else {
throw Context.reportRuntimeError4(
"msg.method.ambiguous", memberClass,
memberName, scriptSignature(args), buf.toString());
}
}
/** Types are equal */
private static final int PREFERENCE_EQUAL = 0;
private static final int PREFERENCE_FIRST_ARG = 1;
private static final int PREFERENCE_SECOND_ARG = 2;
/** No clear "easy" conversion */
private static final int PREFERENCE_AMBIGUOUS = 3;
/**
* Determine which of two signatures is the closer fit.
* Returns one of PREFERENCE_EQUAL, PREFERENCE_FIRST_ARG,
* PREFERENCE_SECOND_ARG, or PREFERENCE_AMBIGUOUS.
*/
private static int preferSignature(Object[] args,
Class[] sig1,
boolean vararg1,
Class[] sig2,
boolean vararg2 )
{
int totalPreference = 0;
for (int j = 0; j < args.length; j++) {
Class type1 = vararg1 && j >= sig1.length ? sig1[sig1.length-1] : sig1[j];
Class type2 = vararg2 && j >= sig2.length ? sig2[sig2.length-1] : sig2[j];
if (type1 == type2) {
continue;
}
Object arg = args[j];
// Determine which of type1, type2 is easier to convert from arg.
int rank1 = NativeJavaObject.getConversionWeight(arg, type1);
int rank2 = NativeJavaObject.getConversionWeight(arg, type2);
int preference;
if (rank1 < rank2) {
preference = PREFERENCE_FIRST_ARG;
} else if (rank1 > rank2) {
preference = PREFERENCE_SECOND_ARG;
} else {
// Equal ranks
if (rank1 == NativeJavaObject.CONVERSION_NONTRIVIAL) {
if (type1.isAssignableFrom(type2)) {
preference = PREFERENCE_SECOND_ARG;
} else if (type2.isAssignableFrom(type1)) {
preference = PREFERENCE_FIRST_ARG;
} else {
preference = PREFERENCE_AMBIGUOUS;
}
} else {
preference = PREFERENCE_AMBIGUOUS;
}
}
totalPreference |= preference;
if (totalPreference == PREFERENCE_AMBIGUOUS) {
break;
}
}
return totalPreference;
}
private static final boolean debug = false;
private static void printDebug(String msg, MemberBox member,
Object[] args)
{
if (debug) {
StringBuffer sb = new StringBuffer();
sb.append(" ----- ");
sb.append(msg);
sb.append(member.getDeclaringClass().getName());
sb.append('.');
if (member.isMethod()) {
sb.append(member.getName());
}
sb.append(JavaMembers.liveConnectSignature(member.argTypes));
sb.append(" for arguments (");
sb.append(scriptSignature(args));
sb.append(')');
System.out.println(sb);
}
}
MemberBox[] methods;
private String functionName;
private transient CopyOnWriteArrayList overloadCache;
}
class ResolvedOverload {
final Class[] types;
final int index;
ResolvedOverload(Object[] args, int index) {
this.index = index;
types = new Class[args.length];
for (int i = 0, l = args.length; i < l; i++) {
Object arg = args[i];
if (arg instanceof Wrapper)
arg = ((Wrapper)arg).unwrap();
types[i] = arg == null ? null : arg.getClass();
}
}
boolean matches(Object[] args) {
if (args.length != types.length) {
return false;
}
for (int i = 0, l = args.length; i < l; i++) {
Object arg = args[i];
if (arg instanceof Wrapper)
arg = ((Wrapper)arg).unwrap();
if (arg == null) {
if (types[i] != null) return false;
} else if (arg.getClass() != types[i]) {
return false;
}
}
return true;
}
@Override
public boolean equals(Object other) {
if (!(other instanceof ResolvedOverload)) {
return false;
}
ResolvedOverload ovl = (ResolvedOverload) other;
return Arrays.equals(types, ovl.types) && index == ovl.index;
}
@Override
public int hashCode() {
return Arrays.hashCode(types);
}
}