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*
* The Original Code is Rhino code, released
* May 6, 1998.
*
* The Initial Developer of the Original Code is
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import org.mozilla.javascript.*;
import java.util.Vector;
/**
* Matrix: An example host object class that implements the Scriptable interface.
*
* Built-in JavaScript arrays don't handle multiple dimensions gracefully: the
* script writer must create every array in an array of arrays. The Matrix class
* takes care of that by automatically allocating arrays for every index that
* is accessed. What's more, the Matrix constructor takes a integer argument
* that specifies the dimension of the Matrix. If m is a Matrix with dimension 3,
* then m[0] will be a Matrix with dimension 1, and m[0][0] will be an Array.
*
* Here's a shell session showing the Matrix object in action:
* <pre>
* js> defineClass("Matrix")
* js> m = new Matrix(2); <i>A constructor call, see <a href="#Matrix">Matrix</a> below.</i>
* [object Matrix] <i>The "Matrix" here comes from <a href"#getClassName">getClassName</a>.</i>
* js> version(120); <i>switch to JavaScript1.2 to see arrays better</i>
* 0
* js> m[0][0] = 3;
* 3
* js> m[0]; <i>an array was created automatically!</i>
* [3]
* js> m[1]; <i>array is created even if we don't set a value</i>
* []
* js> m.dim; <i>we can access the "dim" property</i>
* 2
* js> m.dim = 3;
* 3
* js> m.dim; <i>but not modify it</i>
* 2
* </pre>
*
* @see org.mozilla.javascript.Context
* @see org.mozilla.javascript.Scriptable
*
* @author Norris Boyd
*/
public class Matrix implements Scriptable {
/**
* The zero-parameter constructor.
*
* When ScriptableObject.defineClass is called with this class, it will
* construct Matrix.prototype using this constructor.
*/
public Matrix() {
}
/**
* The Java constructor, also used to define the JavaScript constructor.
*/
public Matrix(int dimension) {
if (dimension <= 0) {
throw Context.reportRuntimeError(
"Dimension of Matrix must be greater than zero");
}
dim = dimension;
v = new Vector();
}
/**
* Returns the name of this JavaScript class, "Matrix".
*/
public String getClassName() {
return "Matrix";
}
/**
* Defines the "dim" property by returning true if name is
* equal to "dim".
* <p>
* Defines no other properties, i.e., returns false for
* all other names.
*
* @param name the name of the property
* @param start the object where lookup began
*/
public boolean has(String name, Scriptable start) {
return name.equals("dim");
}
/**
* Defines all numeric properties by returning true.
*
* @param index the index of the property
* @param start the object where lookup began
*/
public boolean has(int index, Scriptable start) {
return true;
}
/**
* Get the named property.
* <p>
* Handles the "dim" property and returns NOT_FOUND for all
* other names.
* @param name the property name
* @param start the object where the lookup began
*/
public Object get(String name, Scriptable start) {
if (name.equals("dim"))
return new Integer(dim);
return NOT_FOUND;
}
/**
* Get the indexed property.
* <p>
* Look up the element in the associated vector and return
* it if it exists. If it doesn't exist, create it.<p>
* @param index the index of the integral property
* @param start the object where the lookup began
*/
public Object get(int index, Scriptable start) {
if (index >= v.size())
v.setSize(index+1);
Object result = v.elementAt(index);
if (result != null)
return result;
if (dim > 2) {
Matrix m = new Matrix(dim-1);
m.setParentScope(getParentScope());
m.setPrototype(getPrototype());
result = m;
} else {
Context cx = Context.getCurrentContext();
Scriptable scope = ScriptableObject.getTopLevelScope(start);
result = cx.newArray(scope, 0);
}
v.setElementAt(result, index);
return result;
}
/**
* Set a named property.
*
* We do nothing here, so all properties are effectively read-only.
*/
public void put(String name, Scriptable start, Object value) {
}
/**
* Set an indexed property.
*
* We do nothing here, so all properties are effectively read-only.
*/
public void put(int index, Scriptable start, Object value) {
}
/**
* Remove a named property.
*
* This method shouldn't even be called since we define all properties
* as PERMANENT.
*/
public void delete(String id) {
}
/**
* Remove an indexed property.
*
* This method shouldn't even be called since we define all properties
* as PERMANENT.
*/
public void delete(int index) {
}
/**
* Get prototype.
*/
public Scriptable getPrototype() {
return prototype;
}
/**
* Set prototype.
*/
public void setPrototype(Scriptable prototype) {
this.prototype = prototype;
}
/**
* Get parent.
*/
public Scriptable getParentScope() {
return parent;
}
/**
* Set parent.
*/
public void setParentScope(Scriptable parent) {
this.parent = parent;
}
/**
* Get properties.
*
* We return an empty array since we define all properties to be DONTENUM.
*/
public Object[] getIds() {
return new Object[0];
}
/**
* Default value.
*
* Use the convenience method from Context that takes care of calling
* toString, etc.
*/
public Object getDefaultValue(Class typeHint) {
return "[object Matrix]";
}
/**
* instanceof operator.
*
* We mimick the normal JavaScript instanceof semantics, returning
* true if <code>this</code> appears in <code>value</code>'s prototype
* chain.
*/
public boolean hasInstance(Scriptable value) {
Scriptable proto = value.getPrototype();
while (proto != null) {
if (proto.equals(this))
return true;
proto = proto.getPrototype();
}
return false;
}
/**
* Some private data for this class.
*/
private int dim;
private Vector v;
private Scriptable prototype, parent;
}
