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

Constructors
Constructor and Description

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

Constructors
Constructor and Description
`MWJavaObjectRef(java.lang.Object o)` Example: Instantiate a new Builder component object:

Method Summary

Methods
Modifier and Type	Method and Description
`<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.

Class MWJavaObjectRef

Field Summary

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

Constructor Summary

Method Summary

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

Methods inherited from class java.lang.Object

Constructor Detail

MWJavaObjectRef

Method Detail

clone

sharedCopy

equals

hashCode

toString

numberOfElements

numberOfNonZeros

maximumNonZeros

dispose

get

set

classID

toArray

applyVisitor

unwrapJavaObjectRefs

unwrapJavaObjectRefs

numberOfDimensions

getDimensions

isEmpty

isSparse

compareTo

get

get

set

set

getData

setData

rowIndex

columnIndex