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IObserver

Namespace: UTILSLIB  ·  Library: Utilities Library

#include <utils/observerpattern.h>

class UTILSLIB::IObserver

DECLARE INTERFACE OBSERVER.

The IObserver interface provides the base class of every observer of the observer design pattern.

src/examples/ex_utils/main.cpp
// A subject notifies every attached observer; observers pull the state they need
class Counter : public Subject
{
public:
    void increment()
    {
        ++m_value;
        notify();
    }
    int value() const
    {
        return m_value;
    }

private:
    int m_value = 0;
};

class LastSeen : public IObserver
{
public:
    void update(Subject* pSubject) override
    {
        m_seen = static_cast<Counter*>(pSubject)->value();
    }
    int seen() const
    {
        return m_seen;
    }

private:
    int m_seen = -1;
};

Inheritance​

Public Methods​

~IObserver()​

Destroys the IObserver.

update(pSubject)​

Updates the IObserver.

Parameters:

  • pSubject : *Subject ** pointer to the subject where observer is attached to.

Example​

Used in examples​

ex_utils​

Utilities library: buffers, observers, logging, file formats, montages, layouts and reports.

src/examples/ex_utils/main.cpp, line 97
class LastSeen : public IObserver
{
public:
    void update(Subject* pSubject) override
    {
        m_seen = static_cast<Counter*>(pSubject)->value();
    }
    int seen() const
    {
        return m_seen;
    }

Authors of this file​