Download Java in SAS - Richard A. DeVenezia

Java in SAS®
JavaObj, a DATA Step
Component Object
Richard A. DeVenezia
Independent Consultant
SAS is a registered trademark or trademark of SAS Institute Inc. in the USA and other countries. ® indicates USA registration.
Other brand and product names are registered trademarks or Trademarks of their respective companies.
Slide imagery Copyright © 2005, SAS Institute Inc. All rights reserved.
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Overview

Component Object

Component Interface
• Syntax
• Design
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Component Interface

DECLARE Statement

_NEW_ Operator

Object References

Object Methods
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
DECLARE Statement
DECLARE ComponentObject variable;

Places variable in PDV

Variable is an object reference

Cannot be output to a data set
DECLARE ComponentObject variable
( constructor arguments );

Instantiates an object at declaration
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
_NEW_ Operator
DECLARE ComponentObject variable;
variable = _NEW_ (constructor arguments);

Instantiates an object

Pattern of argument types
• signature
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Object References

Object variables refer to an underlying component

Assignable
myObj1
myObj1 == myObj2;
myObj2;
• original myObj1 reference lost!

Terminate objects no longer needed
myObj1.delete();
myObj1.delete();

No documented garbage collection
• some automatic termination
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Object Methods

Object Dot Syntax
myObj . method ( arguments );

Each object has a set of documented methods
• Allows DATA Step to interact with component

Pattern of argument types
• signature
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
JavaObj Component Object

One of three production objects
• Others are Hash, HIter

Constructor signature
( Char, {other args} );
Char - name of Java class
{ other args } - signature of class constructor
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
JVM - Java Virtual Machine

Execution environment for Java classes

Initialized when first JavaObj instantiated
• Persists until SAS session ends
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Java classes

Loaded from CLASSPATH

Must be compatible with active JVM
-JREOPTIONS(-Dsas.jre.home=...)

Class names - hierarchy and nesting
Java code
SAS Code
x.y.z.MyClass
'x/y/z/MyClass'
x.y.MyClass.Foo
'x/y/z/MyClass$Foo'
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
CLASSPATH

Environment Variable
location-1;location-2;...;location-N
Folders or Jar files

Set via
• command line
• configuration file
• invoking process
• user profile
• system profile
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Java fields

Type
• Primitive or Class

Value
• Primitive or Object reference

JavaObj can interact, if
• field is primitive type or String
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Java methods

Have arguments
• signature - pattern of types

Return nothing, a primitive type, or an object

JavaObj can interact
• signature is void
• signature contains doubles, Strings and classes that
JavaObj can instantiate.
-Important!
• if return is not an object (String excluded)
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
JavaObj accessor methods

Allow interaction between DATA Step and
underlying Java object

Fields
javaobj.get[Static]TypeField(field,out-variable)
javaobj.set[Static]TypeField(field,in-expression)

Method
javaobj.call[Static]TypeMethod
(method, in-args, out-variable)
• in-args signature must match method signature

j.getDoubleField (‘score’, score);
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
JavaObj accessor methods
Java: public Type Method (args…) {… return * }
SAS:
javaobj.callTypeMethod ( ‘Method’, args…, return );
SAS:
javaobj.getTypeField ( ‘Field’, out-variable );
Java: public Type Field = value;
SAS:
javaobj.setTypeField ( ‘Field’, in-expression );
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
First Program
data _null_;
declare JavaObj j ('java/lang/String'
,'My first JavaObj');
length s $200;
j.callStringMethod ('toString', s);
put s=;
run;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Second Program - Java
public class Greetings
{
private String[3] phrases = { 'Hello', 'Hi There', '' };
public void setGreeting (String phrase, double index)
{ phrases [ (int) index ] = phrase; }
public String getGreeting ()
{ return phrases [ 0 ]; }
public String getGreeting (double index)
{ return phrases [ (int) index ]; }
}
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Second Program - SAS
data _null_;
declare JavaObj j ('Greetings');
length s1-s3 $200;
j.callStringMethod
j.callStringMethod
j.callVoidMethod
j.callStringMethod
put (s1-s3) (=/);
run;
------ log -----s1=Hello
s2=Hi There
s3=Wassup
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
('getGreeting',
('getGreeting',
('setGreeting',
('getGreeting',
s1);
1, s2);
2, 'Wassup');
2, s3);
JavaObj support methods

Interact with Java exceptions

exceptionDescribe (in-debug-logging)
• use 1 to log exception stack traces on SAS session stderr

exceptionCheck (out-status)
• returns 1 if an exception occurred

exceptionClear ()
• resets status (internal to JavaObj system)
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Third Program - Uh, oh
data _null_;
length s $200;
declare JavaObj j ('Greetings');
j.exceptionDescribe (1);
j.callStringMethod ('getGreeting', 9, s);
j.exceptionCheck (e); put e= s=;
if (e) then do;
put 'An exception occurred.';
j.exceptionClear ();
end;
run;
------ log -----e=1 s=
An exception occurred.
------ stderr -----java.lang.ArrayIndexOutOfBoundsException: 9
at Greetings.getGreeting(Greetings.java:11)
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Java2D

Object oriented approach to Graphics

More colors than SAS/Graph

Anti-aliased drawing

Alpha blending

Affine Transformations

JPG and PNG
• Other formats via plug-in classes
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Fourth Program - Display an Image


Runtime library has many useful classes
Program uses a few
import java.io.File;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JOptionPane;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Fourth Program - SUGI30.Graphics
package SUGI30;
...import statements...
public Graphics {
private String
readSource;
private BufferedImage readBuffer;
void readImage (String source) throws Exception {
readSource = null;
readBuffer = ImageIO.read (new File(source));
readSource = source;
}
void showReadBuffer () {
show ( readBuffer, readSource );
}
void show (BufferedImage img, String title) {
JOptionPane.showMessageDialog(null,null,title,
JOptionPane.PLAIN_MESSAGE, new ImageIcon(img));
}
}
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Fourth Program - SAS

Short and sweet
• Real work occurs ‘over in Java’
data _null_;
declare JavaObj j ('SUGI30/Graphics');
j.exceptionDescribe(1);
j.callVoidMethod ('readImage', 'sugi30_logo.png');
j.callVoidMethod ('showReadBuffer');
j.delete();
run;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Recompiling Java

Occurs often during rapid development
• Corrections or changes made to java source

If done while SAS active
• New version of an already loaded class
will not get loaded !

Solution - use Batch SAS
• Compile Java, then run SAS
• Non-trivial Java systems
-build tool, Ant
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Development Configuration

batch file - example1.bat
• compiles java
• runs SAS program
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Batch for Development
clear log
set program=GraphicsTester
echo . > %program%.log
compile java if not exist class\ mkdir class\
javac -d class\ java\*.java
if errorlevel 1 goto done
sas program
set CLASSPATH=class;%CLASSPATH% 2>stderr.log >stdout.log
sas -sysin sas\%program%.sas
review logs
notepad %program%.log
notepad stderr.log
notepad stdout.log
:done
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
SUGI30.Graphics - An Adapter
private BufferedImage buffer;
private Graphics2D g;
private double antiAlias;
// drawing buffer
// graphics context
// state variable
void createBuffer (double width, double height) {
buffer = new BufferedImage ((int)width,(int)height
,BufferedImage.TYPE_INT_RGB);
g = buffer.createGraphics();
setAntiAlias (1d); // 1 as double
}
void setAntiAlias (double smooth) {
if (smooth != 0d) {
g.setRenderingHint
( RenderingHints.KEY_ANTIALIASING
, RenderingHints.KEY_ANTIALIASING_ON
);
} else { ... }
}
}
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Adapter

Also known as Wrapper

“Convert the interface of a class into another
interface clients expect. Adapter lets classes
work together that couldn’t otherwise because
of incompatible interfaces”
[ Design Patterns - Gang of Four ]

Incompability
• JavaObj passes primitives, Strings and JavaObj
-cannot receive object reference in return
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Drawing (Adapters)
void setColor (double r, double g, double b) {
this.g.setColor (new Color ((int)r,(int)g,(int)b));
}
void drawLine (double x1, double y1, double x2, double y2) {
g.drawLine ( (int) x1, (int) y1, (int) x2, (int) y2);
}
void fillRect (double x, double y, double width, double height) {
g.fillRect ( (int) x, (int) y, (int) width, (int) height);
}
void drawOval (double x, double y, double width, double height) {
g.drawOval ( (int) x, (int) y, (int) width, (int) height);
}
void fillOval (double x, double y, double width, double height) {
g.fillOval ( (int) x, (int) y, (int) width, (int) height);
}
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Saving Graphics
String saveAs ( String type, String name )
{
String savedAs = "";
try {
File file = new File(name);
savedAs = file.getCanonicalPath();
ImageIO.write (buffer, type, new File(savedAs));
}
catch (Exception e) {
savedAs = "";
}
return savedAs;
}
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
GraphicsTester

Notice the j.* pattern
data _null_;
length fname $200;
declare JavaObj j ('SUGI30/Graphics');
j.exceptionDescribe(1);
j.callVoidMethod (’createBuffer', 200,200);
j.callVoidMethod (‘setColor’, 255,255,255);
j.callVoidMethod (‘fillRect’, 0,0,200,200);
j.callVoidMethod (‘setColor’, 255,0,0);
j.callVoidMethod (‘drawOval’, 1,1,198,198);
j.callVoidMethod (‘fillOVal’, 80,80,40,40);
j.callVoidMethod ('saveAs’, ‘png’,‘sqare.png’, fname);
j.callVoidMethod (‘show’, fname, ‘Drawing buffer’);
j.delete();
run;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Emulate DSGI

An adaper surfaces a set of methods

State variables
• Maintain properties of context

Extensible
• Add new methods and states to Graphics.java

Downside
• Not GRSEG compatible

Upside
• Other graphics formats via ImageIO plugins
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Patterns in SAS Code ==> Macro
%macro createBuffer (width, height);
&jdsgi..callVoidMethod ('createBuffer', &width, &height)
%mend;
%macro
setColor ( r , g, b);
&jdsgi..callVoidMethod ('setColor', &r, &g, &b)
%mend;
%macro
fillRect ( x, y, width, height);
&jdsgi..callVoidMethod ('fillRect', &x,&y,&width,&height)
%mend;
and so on...
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Patterns in SAS Code ==> Macro
%macro canvas_create (javaobj, width, height, color);
%global jdsgi;
%let jdsgi = &javaobj;
declare javaobj &jdsgi (‘SUGI30/Graphics’);
&jdsgi..exceptionDescribe(1);
%createBuffer (&width, &height);
%setColor (&color);
%fillRect (0,0,&width,&height);
%setColor (0,0,0);
%mend;
%canvas_delete ();
&jdsgi..delete();
%symdel &jdsgi;
%mend;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
GraphicsTester

Simplifies adapter use
data _null_;
length fname $200;
%canvas_create (_g, 200,200, 255,255,255);
%setColor (255,0,0);
%drawOval (1,1,198,198);
%fillOval (80,80,40,40);
%saveAs (‘png’, ‘target2.png’, fname);
%showTM (savedAs, cat(‘Drawing buffer’,’0a’x,
’Drawn with Macros.’);
%canvas_delete();
run;
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
Conclusion

Component Object technology introduces the concept
of Object to DATA Step

JavaObj is one doorway into the vast domain of Java
based tools and solutions

Extensive jDSGI samples at
www.devenezia.com/downloads/sas/samples/#jdsgi
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.
About the Speaker
Speaker Richard A. DeVenezia
Independent Consultant
Location 9949 East Steuben Road
Remsen, NY 13438
Telephone (315) 831-8802
E-Mail [email protected]
Copyright © 2005 , Richard A. DeVenezia. All rights reserved.