import java.util.*;
/**
- * The public API for the JS engine; JS itself is actually a class
- * implementing the minimal amount of functionality for an Object
- * which can be manipulated by JavaScript code.
+ * 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. The static
+ * methods, fields, and inner classes of JS define the publicly
+ * visible API for the XWT JavaScript engine; code outside this
+ * package should never depend on anything not defined in this file.
*/
public abstract class JS {
+
// Public Helper Methods //////////////////////////////////////////////////////////////////////
+ /** parse and compile a function */
+ public static CompiledFunction parse(String sourceName, int firstLine, Reader sourceCode) throws IOException {
+ return new CompiledFunction(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 Number) return o.equals(new Integer(0));
- return true;
+ if (o == null) return false;
+ if (o instanceof Boolean) return ((Boolean)o).booleanValue();
+ if (o instanceof Number) return o.equals(new Integer(0));
+ return true;
}
+ /** coerce an object to a Long */
public static long toLong(Object o) { return toNumber(o).longValue(); }
+
+ /** 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);
- if (o instanceof String) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(0); }
- 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");
+ if (o == null) return new Long(0);
+ if (o instanceof Number) return ((Number)o);
+ if (o instanceof String) try { return new Double((String)o); } catch (NumberFormatException e) { return new Double(0); }
+ 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");
}
public boolean coerceToBoolean() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Boolean"); }
- // Subclasses /////////////////////////////////////////////////////////////////////////
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
- /** A slightly more featureful version of JS */
+ /** A sensible implementation of the abstract methods in the JS class */
public static class Obj extends JS {
- private Hash entries = new Hash();
- private boolean sealed = false;
- public Obj() { this(false); }
- public Obj(boolean sealed) { this.sealed = sealed; }
- public void setSeal(boolean sealed) { this.sealed = sealed; }
- public Object get(Object key) { return entries.get(key); }
- public void put(Object key, Object val) { if (!sealed) entries.put(key, val); }
- public Object[] keys() { return(entries.keys()); }
+ private Hash entries = new Hash();
+ private boolean sealed = false;
+ public Obj() { this(false); }
+ public Obj(boolean sealed) { this.sealed = sealed; }
+ /** a sealed object cannot have its properties modified */
+ public void setSeal(boolean sealed) { this.sealed = sealed; }
+ public Object get(Object key) { return entries.get(key); }
+ public void put(Object key, Object val) { if (!sealed) entries.put(key, val); }
+ public Object[] keys() { return(entries.keys()); }
}
- /** An exception which can be thrown and caught by JavaScripts */
+ /** 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 String toString() { return "JS.Exn: " + js; }
- public String getMessage() { return toString(); }
- public Object getObject() { return js; }
+ 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 publicly-visible face of JavaScript Array objects */
+ public static class Array extends ArrayImpl {
+ public Array() { }
+ public Array(int size) { super(size); }
+ public void setSize(int i) { super.setSize(i); }
+ public int length() { return super.length(); }
+ public Object elementAt(int i) { return super.elementAt(i); }
+ public void addElement(Object o) { super.addElement(o); }
+ public void setElementAt(Object o, int i) { super.setElementAt(o, i); }
+ public Object get(Object key) { return super.get(key); }
+ public void put(Object key, Object val) { super.put(key, val); }
+ }
+
/** Any object which becomes part of the scope chain must support this interface */
- public static class Scope extends Obj {
- private Scope parentScope;
- private static Object NULL = new Object();
- public Scope(Scope parentScope) { this(parentScope, false); }
- public Scope(Scope parentScope, boolean sealed) { super(sealed); this.parentScope = parentScope; }
- public Scope getParentScope() { return parentScope; }
-
- // transparent scopes are not returned by THIS
- public boolean isTransparent() { return false; }
-
- public boolean has(Object key) { return super.get(key) != null; }
- public Object get(Object key) {
- if (!has(key)) return parentScope == null ? null : getParentScope().get(key);
- Object ret = super.get(key); return ret == NULL ? null : ret;
- }
- public void put(Object key, Object val) {
- if (!has(key) && parentScope != null) getParentScope().put(key, val);
- else super.put(key, val == null ? NULL : val);
- }
- public Object[] keys() { throw new Error("you can't enumerate the properties of a Scope"); }
- public void declare(String s) {
- if (isTransparent()) getParentScope().declare(s);
- else super.put(s, NULL);
- }
+ public static class Scope extends ScopeImpl {
+ public Scope(Scope parentScope) { this(parentScope, false); }
+ public Scope(Scope parentScope, boolean sealed) { super(parentScope, sealed); }
+ /** transparent scopes are not returned by THIS */
+ public boolean isTransparent() { return super.isTransparent(); }
+ public boolean has(Object key) { return super.has(key); }
+ public Object get(Object key) { return super.get(key); }
+ public void put(Object key, Object val) { super.put(key, val); }
+ public void declare(String s) { super.declare(s); }
}
- public static CompiledFunction parse(String sourceName, int firstLine, Reader sourceCode, JS.Scope parentScope) throws IOException {
- return new CompiledFunction(sourceName, firstLine, sourceCode, parentScope);
- }
-
/** anything that is callable with the () operator */
public static abstract class Callable extends JS.Obj {
- public abstract Object call(Array args) throws JS.Exn;
+ public abstract Object call(JS.Array args) throws JS.Exn;
+ }
+
+ /** a Callable which was compiled from JavaScript code */
+ public static class CompiledFunction extends CompiledFunctionImpl {
+ public Object call(JS.Array args, JS.Scope scope) throws JS.Exn { return super.call(args, scope); }
+ CompiledFunction(String sourceName, int firstLine, Reader sourceCode, Scope scope) throws IOException {
+ super(sourceName, firstLine, sourceCode, scope);
+ }
}
+ public static final JS Math = new org.xwt.js.Math();
+
+ /** encapsulates a single JavaScript thread; the JS.Thread->java.lang.Thread mapping is 1:1 */
+ public static class Thread {
+
+ CompiledFunction currentCompiledFunction = null;
+ Vec stack = new Vec();
+ int line = -1;
+
+ /** binds this thread to the current Java Thread */
+ public void bindToCurrentJavaThread() { javaThreadToJSThread.put(java.lang.Thread.currentThread(), this); }
+
+ /** returns the line of code that is currently executing */
+ public int getLine() { return line; }
+
+ /** returns the name of the source code file which declared the currently executing function */
+ public String getSourceName() { return currentCompiledFunction == null ? null : currentCompiledFunction.getSourceName(); }
+
+ /** fetches the currently-executing javascript function */
+ public JS.CompiledFunction getCurrentCompiledFunction() { return currentCompiledFunction; }
+
+
+ // Statics ///////////////////////////////////////////////////////////////////////
+
+ private static Hashtable javaThreadToJSThread = new Hashtable();
+
+ /** returns the JS thread for a given Java thread, creating one if necessary */
+ public static JS.Thread fromJavaThread(java.lang.Thread t) {
+ JS.Thread ret = (JS.Thread)javaThreadToJSThread.get(t);
+ if (ret == null) {
+ ret = new JS.Thread();
+ ret.bindToCurrentJavaThread();
+ }
+ return ret;
+ }
+
+ }
}