External Interfaces/API

Concatenating Java Objects

You can concatenate Java objects in the same way that you concatenate native MATLAB data types. You use either the cat function or the square bracket operators to tell MATLAB to assemble the enclosed objects into a single object.

Concatenating Objects of the Same Class

If all of the objects being operated on are of the same Java class, then the concatenation of those objects produces an array of objects from the same class.

In the following example, the cat function concatenates two objects of the class java.awt.Point. The class of the result is also java.awt.Point.

• point1 = java.awt.Point(24,127);
  point2 = java.awt.Point(114,29);
  
  cat(1, point1, point2)
  ans = 
  java.awt.Point[]:
      [1x1 java.awt.Point]
      [1x1 java.awt.Point]
  

Concatenating Objects of Unlike Classes

When you concatenate objects of unlike classes, MATLAB finds one class from which all of the input objects inherit, and makes the output an instance of this class. MATLAB selects the lowest common parent in the Java class hierarchy as the output class.

For example, concatenating objects of java.lang.Byte, java.lang.Integer, and java.lang.Double yields an object of java.lang.Number, since this is the common parent to the three input classes.

• byte = java.lang.Byte(127);
  integer = java.lang.Integer(52);
  double = java.lang.Double(7.8);
  
  [byte; integer; double]
  
  ans =
  java.lang.Number[]:
      [   127]
      [    52]
      [7.8000]
  

If there is no common, lower level parent, then the resultant class is java.lang.Object, which is the root of the entire Java class hierarchy.

• byte = java.lang.Byte(127);
  point = java.awt.Point(24,127);
  
  [byte; point]
  
  ans =
  java.lang.Object[]:
      [               127]
      [1x1 java.awt.Point]
  

Creating and Using Java Objects

Saving and Loading Java Objects to MAT-Files