com.mathworks.toolbox.javabuilder
Class MWJavaObjectRef

java.lang.Object
  com.mathworks.toolbox.javabuilder.MWArray
      com.mathworks.toolbox.javabuilder.MWJavaObjectRef

All Implemented Interfaces:

Disposable, java.io.Serializable, java.lang.Cloneable, java.lang.Comparable

public class MWJavaObjectRef
extends MWArray

MWJavaObjectRef, a special subclass of MWArray, can be used to create a MATLAB array that references a Java object.

See Also:

Serialized Form

Field Summary

Fields inherited from class com.mathworks.toolbox.javabuilder.MWArray

EMPTY_ARRAY

Constructor Summary

MWJavaObjectRef(java.lang.Object o)
Example: Instantiate a new Builder component object:

Method Summary

<T> T	applyVisitor(AbstractMWArrayVisitor<T> v)
MWClassID	classID() Returns the MATLAB type of this array.
java.lang.Object	clone() Example: Cloning (deep copying) an array
int[]	columnIndex() This method returns an array containing the column index of each element in the underlying MATLAB array.
int	compareTo(java.lang.Object obj) This method compares the MWArray object with the input object.
void	dispose() Frees the native MATLAB array contained by this array.
boolean	equals(java.lang.Object obj) Indicates whether some other array is equal to this one.
java.lang.Object	get() Example: Get information about a referenced object
java.lang.Object	get(int index) Returns the element at the specified 1-based offset in this array.
java.lang.Object	get(int[] index) Returns the element at the specified 1-based index-array in this array.
java.lang.Object	getData() Returns a 1-D array containing a copy of the data in the underlying MATLAB array.
int[]	getDimensions() Returns an array containing the size of each dimension of this array.
int	hashCode() Returns a hash code value for this array.
boolean	isEmpty() This method returns true if the array object contains no elements, and false otherwise.
boolean	isSparse() This method returns true if the MWArray object is sparse, and false otherwise.
int	maximumNonZeros() Returns the allocated capacity of a sparse array.
int	numberOfDimensions() Returns the number of dimensions of this array.
int	numberOfElements() Returns the total number of elements in this array.
int	numberOfNonZeros() Returns the number of non-zero elements in a sparse array.
int[]	rowIndex() This method returns an array containing the row index of each element in the underlying MATLAB array.
void	set(int[] index, java.lang.Object element) Replaces the element at the specified 1-based index-array in this array with the specified element.
void	set(int index, java.lang.Object element) Replaces the element at the specified 1-based offset in this array with the specified element.
void	set(java.lang.Object o) Example: Setting an array to specified values
void	setData(java.lang.Object data)
java.lang.Object	sharedCopy() Example: Creating a shared copy of an array
java.lang.Object[]	toArray() Returns an array containing a copy of the data in the underlying MATLAB array.
java.lang.String	toString() Example: Return string representation of array
static java.lang.Object	unwrapJavaObjectRefs(java.lang.Object obj) Example:
static java.lang.Object[]	unwrapJavaObjectRefs(java.lang.Object[] array) Example:

Methods inherited from class com.mathworks.toolbox.javabuilder.MWArray

disposeArray

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

MWJavaObjectRef

public MWJavaObjectRef(java.lang.Object o)

Example: Instantiate a new Builder component object:

    Hashtable myHash = new Hashtable();
    myHash.put("a", new Integer(3));
    myHash.put("b", new Integer(5));
    MWJavaObjectRef A = new MWJavaObjectRef(myHash);
    System.out.println("A = " + A.toString());
 
    MWArray.disposeArray(A);
 

The result is:

    A = {b=5, a=3}
 

Parameters:

o - The object to reference.

Method Detail

clone

public java.lang.Object clone()
                       throws java.lang.CloneNotSupportedException

Example: Cloning (deep copying) an array

       Hashtable myHash = new Hashtable();
       myHash.put("a", new Integer(3));
       myHash.put("b", new Integer(5));
       MWJavaObjectRef A = new MWJavaObjectRef(myHash);
 
       Object C = A.clone();
       System.out.println("A = " + A.toString() +
                ", Clone of A = " +  
                        C.toString());
 
       myHash.put("c", new Integer(7));
 
       System.out.println("After change: A = " + A.toString() +
                        ", Clone of A = " +  
                        C.toString());
 
       A.set(new Integer(12));
 
       System.out.println("After set: A = " + A.toString() +
                                ", Clone of A = " +  
                                C.toString());
 
       MWArray.disposeArray(A);
       MWArray.disposeArray(C);
 

Initial results:

 A = {b=5, a=3}, Clone of A = {b=5, a=3}
 

Results after change:

 A = {b=5, a=3, c=7}, Clone of A = {b=5, a=3, c=7}
 

Results after set:

 A = 12, Clone of A = {b=5, a=3, c=7}
 

Overrides:

clone in class MWArray

Returns:

An MWArray instance representing a deep copy of the underlying MATLAB array.

Throws:

java.lang.CloneNotSupportedException - - The object's class does not implement the Cloneable interface.

sharedCopy

public java.lang.Object sharedCopy()

Example: Creating a shared copy of an array

       Hashtable myHash = new Hashtable();
       myHash.put("a", new Integer(3));
       myHash.put("b", new Integer(5));
       MWJavaObjectRef A = new MWJavaObjectRef(myHash);
 
       Object S = A.sharedCopy();
       System.out.println("A = " + A.toString() +
                ", Shared copy of A = " +  
                        S.toString());
 
       myHash.put("c", new Integer(7));
 
       System.out.println("After change: A = " + A.toString() +
                                ", Shared copy of A = " +  
                                S.toString());
 
       MWArray.disposeArray(A);
       MWArray.disposeArray(S);
 

Initial results are as follows:

       A = {b=5, a=3}, Shared copy of A = {b=5, a=3}
 

Results after change:

       A = {b=5, a=3, c=7}, Shared copy of A = {b=5, a=3, c=7}
 

Specified by:

sharedCopy in class MWArray

Returns:

An MWArray instance representing a shared copy of the underlying MATLAB array.

equals

public boolean equals(java.lang.Object obj)

Indicates whether some other array is equal to this one.

Example: Indicating if arrays are equal:

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(5));
                        Hashtable myHash2 = new Hashtable();
                        myHash2.put("a", new Integer(3));
                        myHash2.put("b", new Integer(5));
                        MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        MWJavaObjectRef B = new MWJavaObjectRef(myHash);
                        MWJavaObjectRef C = new MWJavaObjectRef(myHash2);
 
                        System.out.println("Do A and B refer to the same object? " + A.equals(B));
                        System.out.println("Do A and C? " + A.equals(C));
 
                        MWArray.disposeArray(A);
                        MWArray.disposeArray(B);
                        MWArray.disposeArray(C);
 

Results are as follows:

          Do A and B refer to the same object? true
          Do A and C? false
 

Specified by:

equals in class MWArray

Parameters:

obj - Object Array to compare with this MWArray object

hashCode

public int hashCode()

Returns a hash code value for this array.

Example: Return hash of array

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(8));
                        MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        int h = A.hashCode();
                        System.out.println("Hash of A is 0x" + Integer.toHexString(h));
 
                        MWArray.disposeArray(A);
 

Results are as follows:

          Hash of A is 0xffffff33
 

Specified by:

hashCode in class MWArray

toString

public java.lang.String toString()

Example: Return string representation of array

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(5));
                        MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        System.out.println("String representation of A is " + A.toString());
 
                        MWArray.disposeArray(A);
 

Results are as follows:

          String representation of A is {b=5, a=3}
 

Specified by:

toString in class MWArray

numberOfElements

public int numberOfElements()

Returns the total number of elements in this array.

Example: Return number of elements in array

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(5));
                        MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        System.out.println("Number of elements in A is " + A.numberOfElements());
 
                        MWArray.disposeArray(A);
 

Results are as follows:

 Number of elements in A is 1
 

Specified by:

numberOfElements in class MWArray

numberOfNonZeros

public int numberOfNonZeros()

Returns the number of non-zero elements in a sparse array. If the underlying array is non-sparse, this method returns the same value as numberOfElements().

Specified by:

numberOfNonZeros in class MWArray

Returns:

Current number of non-zero elements in a sparse array.

maximumNonZeros

public int maximumNonZeros()

Returns the allocated capacity of a sparse array. If the underlying array is non-sparse, this method returns the same value as numberOfElements().

Specified by:

maximumNonZeros in class MWArray

Returns:

Currently allocated number of non-zero elements in a sparse array.

Example: Display maximum number of non-zero elements in array

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
          myHash.put("b", new Integer(5));
                MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        System.out.println("Maximum number of nonzero elements in A is " + A.maximumNonZeros());
 
                        MWArray.disposeArray(A);
 

Results are as follows:

          Maximum number of nonzero elements in A is 1
 

dispose

public void dispose()

Frees the native MATLAB array contained by this array.

Specified by:

dispose in interface Disposable

Specified by:

dispose in class MWArray

get

public java.lang.Object get()

Example: Get information about a referenced object

          Hashtable myHash = new Hashtable();
                myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(5));
                        MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        System.out.println("A.get() = " + A.get());
                        System.out.println("Class of referenced object is " + A.get().getClass().toString());
                        System.out.println("Class of A is " + A.getClass().toString());
 
                        MWArray.disposeArray(A);
 

Results are as follows:

          A.get() = {b=5, a=3}
          Class of referenced object is class java.util.Hashtable
          Class of A is class com.mathworks.toolbox.javabuilder.MWJavaObjectRef
 

set

public void set(java.lang.Object o)

Example: Setting an array to specified values

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(5));
                        MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                        System.out.println("A = " + A.toString());
                        A.set(new Integer(12));
                        System.out.println("After set(), A = " + A.toString());
 
                        MWArray.disposeArray(A);
 

Initial results are as follows:

          A = {b=5, a=3}
 

Results after set:

          A = 12
 

classID

public MWClassID classID()

Returns the MATLAB type of this array.

Specified by:

classID in class MWArray

Returns:

MWClassID of this array

Example: Returning MATLAB type of a given array:

          Hashtable myHash = new Hashtable();
                                myHash.put("a", new Integer(3));
                                myHash.put("b", new Integer(5));
                                MWJavaObjectRef A = new MWJavaObjectRef(myHash);
                                System.out.println("ClassID of A is " + A.classID());

                                MWArray.disposeArray(A);
 

The result is:

          ClassID of A is opaque
 

toArray

public java.lang.Object[] toArray()

Returns an array containing a copy of the data in the underlying MATLAB array. The returned array has the same dimensionality as the underlying MATLAB array. The elements of the returned array are converted according to default conversion rules. If the underlying MATLAB array is a complex numeric type, toArray returns the real part. If the underlying array is sparse, a full representation of the array is returned. Care should be taken when calling toArray on a sparse array with large row and column dimensions, as this action may exhaust system memory. If the underlying array is a cell or struct array, toArray is recursively called on each cell.

Specified by:

toArray in class MWArray

Returns:

An array with the same dimensionality of the MATLAB array.

Example: Return array containing a copy of the data in underlying array plus additional information about array

          Integer myInt = new Integer(2);
                        System.out.println("myInts = " + myInt.toString());
                        MWJavaObjectRef A = new MWJavaObjectRef(myInt);
                        Object[] B = A.toArray();
                        System.out.println("Array form is an instance of " + B.getClass().toString());
                        System.out.println("B = " + B);
                        System.out.println("Each element is an instance of " + B[0].getClass().toString());
                        System.out.println("B[0] = " + B[0]);
                        System.out.println("A is an instance of " + A.getClass().toString());
 
                        MWArray.disposeArray(A);
 

Results are as follows:

          myInts = 2
          Array form is an instance of class [Ljava.lang.Object;
          B = [Ljava.lang.Object;@1d53f5b
          Each element is an instance of class java.lang.Integer
          B[0] = 2
          A is an instance of class com.mathworks.toolbox.javabuilder.MWJavaObjectRef
 

applyVisitor

public <T> T applyVisitor(AbstractMWArrayVisitor<T> v)

Specified by:

applyVisitor in class MWArray

unwrapJavaObjectRefs

public static java.lang.Object unwrapJavaObjectRefs(java.lang.Object obj)

Example:

          Hashtable myHash = new Hashtable();
                        myHash.put("a", new Integer(3));
                        myHash.put("b", new Integer(5));
                        MWJavaObjectRef A = new MWJavaObjectRef(new Integer(12));
                        System.out.println("A referenced the object: " + MWJavaObjectRef.unwrapJavaObjectRefs(A));
 
                        MWJavaObjectRef B = new MWJavaObjectRef(myHash);
                        Object bObj = (Object)B;
                        System.out.println("B referenced the object: " + MWJavaObjectRef.unwrapJavaObjectRefs(bObj));
 

Results are as follows:

          A referenced the object: 12
          B referenced the object: {b=5, a=3}
 

unwrapJavaObjectRefs

public static java.lang.Object[] unwrapJavaObjectRefs(java.lang.Object[] array)

Example:

          MWJavaObjectRef A = new MWJavaObjectRef(new Integer(12));
                        MWJavaObjectRef B = new MWJavaObjectRef(new Integer(104));
                        Object[] refArr = new Object[2];
                        refArr[0] = A;
                        refArr[1] = B;
                        Object[] objArr = MWJavaObjectRef.unwrapJavaObjectRefs(refArr);
                        System.out.println("refArr referenced the objects: " + objArr[0] + " and " + objArr[1]);
 

Results are as follows:

          refArr referenced the objects: 12 and 104
 

numberOfDimensions

public int numberOfDimensions()

Description copied from class: MWArray

Returns the number of dimensions of this array. This example uses a 3-by-6 MWNumericArray object A, as constructed by this Java code:

 int[][] Adata = {{ 1, 2, 3, 4, 5, 6},
                  { 7, 8, 9, 10, 11, 12},
                  {13, 14, 15, 16, 17, 18}};
 
 MWNumericArray A = new MWNumericArray(Adata, MWClassID.INT32);
 

Example: Getting the Number of Dimensions of an MWArray Display the number of dimensions for array object A:

 System.out.println("Matrix A has " + A.numberOfDimensions() +
                    " dimensions");
 

When run, the example displays this output:

 Matrix A has 2 dimensions
 

Specified by:

numberOfDimensions in class MWArray

getDimensions

public int[] getDimensions()

Description copied from class: MWArray

Returns an array containing the size of each dimension of this array. This example uses a 3-by-6 MWNumericArray object A, as constructed by this Java code:

 int[][] Adata = {{ 1, 2, 3, 4, 5, 6},
                  { 7, 8, 9, 10, 11, 12},
                  {13, 14, 15, 16, 17, 18}};
 
 MWNumericArray A = new MWNumericArray(Adata, MWClassID.INT32);
 

Example: Getting Array Dimensions of an MWArray

 int[] dimA = A.getDimensions();
 System.out.println("Dimensions of A are " +
                    dimA[0] + " x " + dimA[1]);
 

When run, the example displays this output:

 Dimensions of A are 3 x 6
 

Specified by:

getDimensions in class MWArray

isEmpty

public boolean isEmpty()

Description copied from class: MWArray

This method returns true if the array object contains no elements, and false otherwise. This example uses a 3-by-6 MWNumericArray object A, as constructed by this Java code:

 int[][] Adata = {{ 1, 2, 3, 4, 5, 6},
                  { 7, 8, 9, 10, 11, 12},
                  {13, 14, 15, 16, 17, 18}};
 
 MWNumericArray A = new MWNumericArray(Adata, MWClassID.INT32);
 

Example: Testing for an Empty MWArray Display a message if array object A is an empty array. Otherwise, display the contents of A:

 if (A.isEmpty())
    System.out.println("Matrix A is empty");
 else
    System.out.println("A = " + A.toString());
 

When run, the example displays the contents of A:

 A= 1    2   3   4   5   6
    7    8   9  10  11  12
    13  14  15  16  17  18
 

Specified by:

isEmpty in class MWArray

isSparse

public boolean isSparse()

Description copied from class: MWArray

This method returns true if the MWArray object is sparse, and false otherwise.

The contents of the sparse MWArray, created by the newSparse method, used in the following example is:

   (2,1) 50
   (1,2) 10
   (2,2) 60
   (1,5) 40
   (2,5) 90
 

Example: Testing an MWArray for Sparseness Test the MWArray object A created previously for sparseness:

 if (A.isSparse())
     System.out.println("Matrix A is sparse");
 

When run, the example displays this output:

 Matrix A is sparse
 

Specified by:

isSparse in class MWArray

compareTo

public int compareTo(java.lang.Object obj)

Description copied from class: MWArray

This method compares the MWArray object with the input object. It returns a negative integer, zero, or a positive integer if the MWArray object is less than, equal to, or greater than the specified object, respectively.

Example: Comparing MWArrays with compareTo Create a shared copy of the MWArray object and then compare it to the original object. A return value of zero indicates that the two objects are equal:

 Object S = A.sharedCopy();
 if (A.compareTo(S) == 0)
     System.out.println("Matrix S is equal to matrix A");
 

When run, the example displays this output:

 Matrix S is equal to matrix A
 

Specified by:

compareTo in interface java.lang.Comparable

Specified by:

compareTo in class MWArray

Parameters:

obj - Object Array to compare with this MWArray object

get

public java.lang.Object get(int index)

Description copied from class: MWArray

Returns the element at the specified 1-based offset in this array. Offers better performance than public Object get(int[] index).

Example: Getting an MWArray Value with get

 int[] cdims = {1, 3};
          MWArray C = new MWArray(cdims);
          Integer val = new Integer(15);
          int[] index2 = {1, 3};
          C.set(index2, val);
          Object x = C.get(index2);
          if (x instanceof int[][])
          {
           int[][] y = (int[][])x;
               System.out.println("B: Cell data C(1,3) is " + y[0][0]);
          }
 

When run, the example displays this output:

 B: Cell data C(1,3) is 15
 

Specified by:

get in class MWArray

Parameters:

index - The index of the requested element. Valid range: 1 <= index <= N, where N = total number of elements in the array.

Returns:

Object containing the requested element.

get

public java.lang.Object get(int[] index)

Description copied from class: MWArray

Returns the element at the specified 1-based index-array in this array.

Specified by:

get in class MWArray

Parameters:

index - Array of indices specifying the location of the requested element. The length of the index array must be exactly the number of dimensions of this array. Each element of the index array has the valid range: 1 <= index[i] <= N[i], where N[i] = the size of the ith dimension.

Returns:

Object containing the requested element.

set

public void set(int index,
                java.lang.Object element)

Description copied from class: MWArray

Replaces the element at the specified 1-based offset in this array with the specified element. Offers better performance than public void set(int[] index, Object element).

Example: Setting an MWArray Value Modify the data in element (2, 4) of MWArray object A:

 int[] index = {2, 4};
 A.set(index, 555);
 
 Object d_out = A.get(index);
 System.out.println("Data read from A(2,4) is " +
                     d_out.toString());
 

When run, the example displays this output:

 Data read from A(2,4) is 555
 

Specified by:

set in class MWArray

Parameters:

index - The index of the element to replace. Valid range: 1 <= index <= N, where N = total number of elements in the array.

element - New element to replace at index.

set

public void set(int[] index,
                java.lang.Object element)

Description copied from class: MWArray

Replaces the element at the specified 1-based index-array in this array with the specified element.

Specified by:

set in class MWArray

Parameters:

index - Array of indices specifying the location of the element to replace. The length of the index array must be exactly the number of dimensions of this array. Each element of the index array has the valid range: 1 <= index[i] <= N[i], where N[i] = the size of the ith dimension.

element - New element to replace at index.

getData

public java.lang.Object getData()

Description copied from class: MWArray

Returns a 1-D array containing a copy of the data in the underlying MATLAB array. The elements of the returned array are converted according to default conversion rules. If the underlying MATLAB array is a complex numeric type, getData returns the real part. If the underlying array is a cell or struct array, toArray is recursively called on each cell.

Example: Getting an MWArray Value with getData Get the data from MWArray object A, casting the type from Object to int:

 System.out.println("Data read from matrix A is:");
 int[] x = (int[]) A.getData();
 for (int i = 0; i < x.length; i++)
     System.out.print(" " + x[i]);
 
 System.out.println();
 

When run, the example displays this output:

 Data read from matrix A is:
   1 7 13 2 8 14 3 9 15 4 10 16 5 11 17 6 12 18
 

Specified by:

getData in class MWArray

Returns:

A 1-D array of elements stored in column-wise order. The length of the returned array equals MWArray.numberOfElements() for a non-sparse array, and MWArray.numberOfNonZeros() for a sparse array.

setData

public void setData(java.lang.Object data)

Specified by:

setData in class MWArray

rowIndex

public int[] rowIndex()

Description copied from class: MWArray

This method returns an array containing the row index of each element in the underlying MATLAB array.

The contents of the sparse MWArray, created by the newSparse method, used in the following example is:

   (2,1) 50
   (1,2) 10
   (2,2) 60
   (1,5) 40
   (2,5) 90
 

Example: Getting the Row Indices of a Sparse MWArray Get the row indices of the elements of the sparse array:

 System.out.print("Row indices are: ");
 int[] rowidx = A.rowIndex();
 for (int i = 0; i < 5; i++)
     System.out.print(rowidx[i] + " ");
 System.out.println();
 

When run, the example displays this output:

 Row indices are: 2 1 2 1 2
 

Specified by:

rowIndex in class MWArray

Returns:

Array of indices.

columnIndex

public int[] columnIndex()

Description copied from class: MWArray

This method returns an array containing the column index of each element in the underlying MATLAB array.

The contents of the sparse MWArray, created by the newSparse method, used in the following example is:

   (2,1) 50
   (1,2) 10
   (2,2) 60
   (1,5) 40
   (2,5) 90
 

Example: Getting the Column Indices of a Sparse MWArray Get the column indices of the elements of the sparse array:

 System.out.print("Column indices are: ");
 int[] colidx = A.columnIndex();
 for (int i = 0; i < 5; i++)
     System.out.print(colidx[i] + " ");
 System.out.println();
 

When run, the example displays this output:

 Column indices are: 1 2 2 5 5
 

Specified by:

columnIndex in class MWArray

Returns:

Array of indices.