TextComponentTest.java 文件源码

public void testAddRemoveTextListener() {
    textComp.addTextListener(listener);
    assertSame(listener, textComp.textListener);
    TextListener newListener = new MyTextListener();
    textComp.addTextListener(newListener);
    assertTrue("if there are several listeners multicaster is used",
               textComp.textListener instanceof AWTEventMulticaster);
    AWTEventMulticaster aem = (AWTEventMulticaster) textComp.textListener;
    assertSame(listener, aem.a);
    textComp.removeTextListener(listener);
    assertTrue("if there is only one listener then it is used",
               textComp.textListener instanceof MyTextListener);
    assertSame(newListener, textComp.textListener);
    textComp.removeTextListener(newListener);
    assertNull(textComp.textListener);

}