-// 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 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. 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;
+ }
+
+ /** 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");
+ }
+
+
+ // Instance Methods ////////////////////////////////////////////////////////////////////
-/** The public API for the JS engine */
-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 boolean coerceToBoolean() 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. */
+ public abstract Object get(Object key) throws JS.Exn;
+ public abstract void put(Object key, Object val) throws JS.Exn;
+ public abstract Object[] keys();
+
+ public Number coerceToNumber() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Number"); }
+ public String coerceToString() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a String"); }
+ public boolean coerceToBoolean() { throw new Error("you cannot coerce a " + this.getClass().getName() + " into a Boolean"); }
+
+
+ // Inner Classes /////////////////////////////////////////////////////////////////////////
+
+ /** 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; }
+ /** 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 JavaScript code */
public static class Exn extends RuntimeException {
- private Object js = null;
- public Exn(Object js) { this.js = js; }
- 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 interface Scope extends JS {
- public boolean has(Object key);
- public void declare(String s);
- public JS getParentScope();
+ 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); }
}
+
+ /** anything that is callable with the () operator */
+ public static abstract class Callable extends JS.Obj {
+ 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();
- /** 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"); }
- }
- */
+ /** 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;
+ }
+
+ }
}
+
+
+
+
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