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// **********************************************************************
//
// Copyright (c) 2003-2014 ZeroC, Inc. All rights reserved.
//
// This copy of Ice is licensed to you under the terms described in the
// ICE_LICENSE file included in this distribution.
//
// **********************************************************************
package Ice;
/**
* Generic class for optional parameters.
**/
public class Optional<T>
{
/**
* The value defaults to unset.
**/
public Optional()
{
_isSet = false;
}
/**
* Sets the value to the given argument.
*
* @param v The initial value.
**/
public Optional(T v)
{
_value = v;
_isSet = true;
}
/**
* Sets the value to a shallow copy of the given optional.
*
* @param opt The source value.
**/
public Optional(Optional<T> opt)
{
_value = opt._value;
_isSet = opt._isSet;
}
/**
* Obtains the current value.
*
* @return The current value.
* @throws IllegalStateException If the value is not set.
**/
public T get()
{
if(!_isSet)
{
throw new IllegalStateException("no value is set");
}
return _value;
}
/**
* Sets the value to the given argument.
*
* @param v The new value.
**/
public void set(T v)
{
_value = v;
_isSet = true;
}
/**
* If the given argument is set, this optional is set to a shallow copy of the argument,
* otherwise this optional is unset.
*
* @param opt The source value.
**/
public void set(Optional<T> opt)
{
_value = opt._value;
_isSet = opt._isSet;
}
/**
* Determines whether the value is set.
*
* @return True if the value is set, false otherwise.
**/
public boolean isSet()
{
return _isSet;
}
/**
* Unsets this value.
**/
public void clear()
{
_isSet = false;
_value = null;
}
/**
* Helper function for creating Optional instances.
*
* @param v The initial value of the Optional.
*
* @return A new Optional instance set to the given value.
**/
public static <T> Optional<T> O(T v)
{
return new Optional<T>(v);
}
/**
* Helper function for creating BooleanOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new BooleanOptional instance set to the given value.
**/
public static BooleanOptional O(boolean v)
{
return new BooleanOptional(v);
}
/**
* Helper function for creating ByteOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new ByteOptional instance set to the given value.
**/
public static ByteOptional O(byte v)
{
return new ByteOptional(v);
}
/**
* Helper function for creating ShortOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new ShortOptional instance set to the given value.
**/
public static ShortOptional O(short v)
{
return new ShortOptional(v);
}
/**
* Helper function for creating IntOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new IntOptional instance set to the given value.
**/
public static IntOptional O(int v)
{
return new IntOptional(v);
}
/**
* Helper function for creating LongOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new LongOptional instance set to the given value.
**/
public static LongOptional O(long v)
{
return new LongOptional(v);
}
/**
* Helper function for creating FloatOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new FloatOptional instance set to the given value.
**/
public static FloatOptional O(float v)
{
return new FloatOptional(v);
}
/**
* Helper function for creating DoubleOptional instances.
*
* @param v The initial value of the Optional.
*
* @return A new DoubleOptional instance set to the given value.
**/
public static DoubleOptional O(double v)
{
return new DoubleOptional(v);
}
private T _value;
private boolean _isSet;
}
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