-// Copyright 2002 Adam Megacz, see the COPYING file for licensing [GPL]
-
+// Copyright 2003 Adam Megacz, see the COPYING file for licensing [GPL]
+
package org.xwt.js;
import org.xwt.util.*;
+import org.xwt.*;
+import java.io.*;
+import java.util.*;
+
+/**
+ * The public API for the JS engine. JS itself is actually a class
+ * implementing the absolute minimal amount of functionality for an
+ * Object which can be manipulated by JavaScript code.
+ */
+public class JS {
+
+ // Public Helper Methods //////////////////////////////////////////////////////////////////////
+
+ /** parse and compile a function */
+ public static JSFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+ return new JSFunction(sourceName, firstLine, sourceCode, null);
+ }
+
+ /** coerce an object to a Boolean */
+ public static boolean toBoolean(Object o) {
+ if (o == null) return false;
+ if (o instanceof Boolean) return ((Boolean)o).booleanValue();
+ if (o instanceof Long) return ((Long)o).longValue() != 0;
+ if (o instanceof Integer) return ((Integer)o).intValue() != 0;
+ if (o instanceof Number) {
+ double d = ((Number) o).doubleValue();
+ // NOTE: d == d is a test for NaN. It should be faster than Double.isNaN()
+ return d != 0.0 && d == d;
+ }
+ if (o instanceof String) return ((String)o).length() != 0;
+ return true;
+ }
+
+ /** coerce an object to a Long */
+ public static long toLong(Object o) { return toNumber(o).longValue(); }
+
+ /** coerce an object to an Int */
+ public static int toInt(Object o) { return toNumber(o).intValue(); }
+
+ /** coerce an object to a Double */
+ public static double toDouble(Object o) { return toNumber(o).doubleValue(); }
+
+ /** coerce an object to a Number */
+ public static Number toNumber(Object o) {
+ if (o == null) return new Long(0);
+ if (o instanceof Number) return ((Number)o);
+
+ // NOTE: There are about 3 pages of rules in ecma262 about string to number conversions
+ // We aren't even close to following all those rules. We probably never will be.
+ if (o instanceof String)
+ try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(Double.NaN); }
+ if (o instanceof Boolean) return ((Boolean)o).booleanValue() ? new Long(1) : new Long(0);
+ if (o instanceof JS) return ((JS)o).coerceToNumber();
+ throw new Error("toNumber() got object of type " + o.getClass().getName() + " which we don't know how to handle");
+ }
+
+ /** coerce an object to a String */
+ public static String toString(Object o) {
+ if(o == null) return "null";
+ if(o instanceof String) return (String) o;
+ if(o instanceof Integer || o instanceof Long || o instanceof Boolean) return o.toString();
+ if(o instanceof JS) return ((JS)o).coerceToString();
+ if(o instanceof Double || o instanceof Float) {
+ double d = ((Number)o).doubleValue();
+ if((int)d == d) return Integer.toString((int)d);
+ return o.toString();
+ }
+ return o.toString();
+ }
+
+ // Instance Methods ////////////////////////////////////////////////////////////////////
-/** all objects other than Strings and Numbers which are exposed to JS code must implement this interface */
-public interface JS {
-
- public Object get(Object key) throws JS.Exn;
- public Object put(Object key, Object val) throws JS.Exn;
- public Object[] enumerateProperties();
- public String coerceToString() throws JS.Exn;
- public Num coerceToNumber() throws JS.Exn;
- public Object call(Object[] args) throws JS.Exn;
-
- /** if JS calls a Java method, and the Java method throws an exception, it can only be caught by JS if it is a subclass of Exn. */
+ // this gets around a wierd fluke in the Java type checking rules for ?..:
+ public static final Object T = Boolean.TRUE;
+ public static final Object F = Boolean.FALSE;
+
+ // FEATURE: be smart here; perhaps intern
+ public static final Number N(int i) { return new Integer(i); }
+ public static final Number N(long l) { return new Long(l); }
+ public static final Number N(double d) { return new Double(d); }
+ public static final Boolean B(boolean b) { return b ? Boolean.TRUE : Boolean.FALSE; }
+
+ private static Enumeration emptyEnumeration = new Enumeration() {
+ public boolean hasMoreElements() { return false; }
+ public Object nextElement() { throw new NoSuchElementException(); }
+ };
+
+ private Hash entries = null;
+ public Enumeration keys() { return entries == null ? emptyEnumeration : entries.keys(); }
+ public Object get(Object key) { return entries == null ? null : entries.get(key, null); }
+ public void put(Object key, Object val) { if (entries == null) entries = new Hash(); entries.put(key, null, val); }
+
+ // note that we don't actually implement trappable... we just provide these for subclasses which choose to
+ public JSTrap getTrap(Object key) { return entries == null ? null : (JSTrap)entries.get(key, JSTrap.class); }
+ public void putTrap(Object key, JSTrap t) { if (entries == null) entries = new Hash(); entries.put(key, JSTrap.class, t); }
+
+ public Number coerceToNumber() { throw new JS.Exn("tried to coerce a JavaScript object to a Number"); }
+ public String coerceToString() { throw new JS.Exn("tried to coerce a JavaScript object to a String"); }
+ public boolean coerceToBoolean() { throw new JS.Exn("tried to coerce a JavaScript object to a Boolean"); }
+
+ public String typeName() { return "object"; }
+
+
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
+
+ /** An exception which can be thrown and caught by JavaScript code */
public static class Exn extends RuntimeException {
- private Object js = null;
- public Exn(Object js) { this.js = js; }
- public Object getObject() { return js; }
- }
-
- /** Any object which becomes part of the scope chain must support this interface */
- public static interface Scope extends JS {
- public boolean has(Object key);
- public void declare(String s);
- public JS getParentScope();
- }
-
- /** A mutable, boxed numeric value. These are recycled -- never duplicate references -- use duplicate() instead. */
- public static class Num implements Cloneable, JS {
-
- private Num() { }
-
- public boolean isDouble = false;
- public long longVal = -1;
- public double doubleVal = -1;
-
- private static Vec pool = new Vec();
- public static synchronized void recycle(Num n) { pool.push(n); }
- public static synchronized Num getOne() { return (pool.size() > 0) ? (Num)pool.pop() : new Num(); }
-
- public Num duplicate() { try { return (Num)clone(); } catch (CloneNotSupportedException c) { throw new Error(c); } }
-
- public Object get(Object key) throws JS.Exn { return null; }
- public Object put(Object key, Object val) throws JS.Exn { throw new JS.Exn("attempt to set a property on a Number"); }
- public Object[] enumerateProperties() { return new Object[] { }; }
- public String coerceToString() throws JS.Exn { return isDouble ? String.valueOf(doubleVal) : String.valueOf(longVal); }
- public Num coerceToNumber() throws JS.Exn { return duplicate(); }
- public Object call(Object[] args) throws JS.Exn { throw new JS.Exn("attempt to apply the () operator to a Number"); }
-
+ private Object js = null;
+ public Exn(Object js) { this.js = js; }
+ public String toString() { return "JS.Exn: " + js; }
+ public String getMessage() { return toString(); }
+ public Object getObject() { return js; }
}
+
+ /** the result of a graft */
+ // FIXME: uber-broken
+ public static class Graft extends JSCallable {
+ private JS graftee;
+ private Object replaced_key;
+ private Object replaced_val;
+ public Graft(Object graftee, Object key, Object val) {
+ if (graftee instanceof JSArray) throw new JS.Exn("can't graft onto JSArrays (yet)");
+ if (graftee instanceof JSCallable) throw new JS.Exn("can't graft onto JSCallables (yet)");
+ if (graftee instanceof JSScope) throw new JS.Exn("can't graft onto JSScopes (yet)");
+ this.graftee = (JS)graftee;
+ replaced_key = key;
+ replaced_val = val;
+ }
+ public boolean equals(Object o) { return (this == o || graftee.equals(o)); }
+ public int hashCode() { return graftee.hashCode(); }
+ public Object get(Object key) { return replaced_key.equals(key) ? replaced_val : graftee.get(key); }
+ public void put(Object key, Object val) { graftee.put(key, val); }
+ /*
+ public Object call(Object method, JSArray args) {
+ if (replaced_key.equals(method)) return ((JSCallable)replaced_val).call(null, args);
+ else if (graftee instanceof JSCallable) return ((JSCallable)graftee).call(method, args);
+ else throw new JS.Exn("cannot call this value");
+ }
+ */
+ public Number coerceToNumber() { return graftee.coerceToNumber(); }
+ public String coerceToString() { return graftee.coerceToString(); }
+ public boolean coerceToBoolean() { return graftee.coerceToBoolean(); }
+ public String typeName() { return graftee.typeName(); }
+ public Enumeration keys() {
+ return new Enumeration() {
+ Enumeration graftee_enumeration = graftee.keys();
+ boolean returned_replaced = false;
+ public boolean hasMoreElements() {
+ if (graftee_enumeration.hasMoreElements()) return true;
+ return !returned_replaced;
+ }
+ public Object nextElement() {
+ if (!graftee_enumeration.hasMoreElements()) {
+ if (returned_replaced) throw new NoSuchElementException();
+ returned_replaced = true;
+ return replaced_key;
+ } else {
+ Object ret = graftee_enumeration.nextElement();
+ if (!returned_replaced && ret.equals(replaced_key)) returned_replaced = true;
+ return ret;
+ }
+ }
+ };
+ }
+ }
}
+
+
+
+
projects / org.ibex.core.git / blobdiff