IgnorantObserver.java

import android.arch.lifecycle.Observer;
import android.support.annotation.Nullable;

public abstract class IgnorantObserver<T> implements Observer<T>{
    private boolean isIgnoring = false;
    private boolean doingIgnorantly = false;

    public IgnorantObserver(){
        this(false);
    }

    public IgnorantObserver(boolean isIgnoring){
        this.isIgnoring = isIgnoring;
    }

    @Override
    public final void onChanged(@Nullable T t) {
        if((!isIgnoring)&&(!doingIgnorantly)) ignorantOnChanged(t);
    }

    public final void ignore(boolean ignore){
        isIgnoring = ignore;
    }

    /**
     *  returns false when executing doIgnorantly even if underling value is true
     *  use isUnderlyingIgnoring() instead for that
     */
    public final boolean isIgnoring(){
        return isIgnoring && !doingIgnorantly;
    }

    public final boolean isUnderlingIgnoring(){
        return isIgnoring;
    }

    /**
     * execute and ignore all onChanged events for this observer while running
     * calls to ignore will not take effect until this returns
     */
    public final void doIgnorantly(Function f){
        boolean isNestedDoIgnorantly = doingIgnorantly;
        doingIgnorantly = true;

        f.run();

        doingIgnorantly = isNestedDoIgnorantly;
    }

    public interface Function{ public void run();}

    /**
     *  called by onChanged only when not ignoring
     */
    protected abstract void ignorantOnChanged(@Nullable T t);

}

userObserver.doIgnorantly(() -> { session.updateUserName("bob"); });