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package com.sun.appserv.management.util.misc;
import java.util.Set;
import java.util.HashSet;
import java.util.Collections;
import java.lang.reflect.Array;
import com.sun.appserv.management.util.misc.ClassUtil;
/**
Provides:
- methods to convert arrays of primitive types to corresponding arrays of Object types
- conversion to/from Set
*/
public final class ArrayConversion
{
private
ArrayConversion( )
{
// disallow instantiation
}
private static Object []
convert( Object simpleArray )
{
if ( ! ClassUtil.objectIsPrimitiveArray( simpleArray ) )
{
throw new IllegalArgumentException();
}
final String className = simpleArray.getClass().getName();
final Class theClass = ClassUtil.getArrayElementClass( simpleArray.getClass() );
final int numItems = Array.getLength( simpleArray );
final Class elementClass = ClassUtil.PrimitiveClassToObjectClass( theClass );
final Object [] result = (Object [])Array.newInstance( elementClass, numItems );
for( int i = 0; i < numItems; ++i )
{
result[ i ] = Array.get( simpleArray, i );
}
return( result );
}
/**
Convert an an array of primitive types to an array of Objects of non-primitive
types eg int to Integer.
@param array the array to convert
*/
public static Object []
toAppropriateType( Object array)
{
return( (Object [])convert( array ) );
}
public static Boolean []
toBooleans( boolean [] array )
{
return( (Boolean [])convert( array ) );
}
public static Character []
toCharacters( char [] array )
{
return( (Character [])convert( array ) );
}
public static Byte []
toBytes( byte [] array )
{
return( (Byte [])convert( array ) );
}
public static Short []
toShorts( short [] array )
{
return( (Short [])convert( array ) );
}
public static Integer []
toIntegers( int [] array )
{
return( (Integer [])convert( array ) );
}
public static Long []
toLongs( long [] array )
{
return( (Long [])convert( array ) );
}
public static Float []
toFloats( float [] array )
{
return( (Float [])convert( array ) );
}
public static Double []
toDoubles( double [] array )
{
return( (Double [])convert( array ) );
}
/**
Create an array whose type is elementType[] of specified size.
@param elementType the type of each entry of the array
@param size the number of elements
*/
public static Object []
createObjectArrayType( final Class elementType, final int size )
{
final Object [] result = (Object []) Array.newInstance( elementType, size );
return( result );
}
public static Object[]
subArray( final Object[] in, int start, int end )
{
final int count = 1 + (end - start);
final Object[] result = (Object[])
Array.newInstance( ClassUtil.getArrayElementClass( in.getClass() ), count );
for( int i = 0; i < count; ++i )
{
result[ i ] = in[ i + start ];
}
return( result );
}
public static <T> Set<T>
toSet( T[] array )
{
Set<T> theSet = null;
if ( array.length == 0 )
{
theSet = Collections.emptySet();
}
else if ( array.length == 1 )
{
theSet = Collections.singleton( array[ 0 ] );
}
else
{
theSet = new HashSet<T>();
for( int i = 0; i < array.length; ++i )
{
theSet.add( array[ i ] );
}
}
return( theSet );
}
/*
Return true if every element of the array has *exactly* the same class.
*/
public static boolean
hasIdenticalElementClasses( final Object [] a )
{
boolean isUniform = true;
if ( a.length > 0 )
{
final Class matchType = a[ 0 ].getClass();
for( int i = 1; i < a.length; ++i )
{
if ( a[ i ].getClass() != matchType )
{
isUniform = false;
break;
}
}
}
return( isUniform );
}
/**
Specialize the type of the array (if possible). For example, if the
array is an Object[] of Integer, return an Integer[] of Integer.
@param a the array to specialize
@return a specialized array (if possible) otherwise the original array
*/
public static Object []
specializeArray( final Object [] a )
{
Object[] result = a;
if ( hasIdenticalElementClasses( a ) &&
a.length != 0 &&
a.getClass() == Object[].class )
{
result = createObjectArrayType( a[0].getClass(), a.length );
System.arraycopy( a, 0, result, 0, a.length );
}
return( result );
}
/**
Convert a Set to an array. If specialize is true, then provide
the most specialized type possible via specializeArray()
@param s the Set to convert
@param specialize decide whether to specialize the type or not
*/
public static Object []
setToArray( final Set<?> s, boolean specialize )
{
Object [] result = setToArray( s );
if ( specialize && result.length != 0)
{
result = specializeArray( result );
}
return( result );
}
/**
Convert a Set to an Object[].
@param s the Set to convert
*/
public static Object []
setToArray( final Set<?> s )
{
final Object [] out = new Object [ s.size() ];
setToArray( s, out );
return( out );
}
/**
Convert a Set to an Object[].
@param s the Set to convert
@param out the output array, must be of size s.size()
*/
public static Object[]
setToArray( final Set<?> s, Object[] out )
{
if ( out.length != s.size() )
{
throw new IllegalArgumentException();
}
int i = 0;
for( final Object o : s )
{
out[ i ] = o;
++i;
}
return( out );
}
public static <T> Set<T>
arrayToSet( final T [] names )
{
final Set<T> set = new HashSet<T>();
for( int i = 0; i < names.length; ++i )
{
set.add( names[ i ] );
}
return( set );
}
}
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