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/*
@VaadinApache2LicenseForJavaFiles@
*/
package com.vaadin.terminal;
import com.vaadin.terminal.gwt.server.ClientConnector;
public abstract class AbstractExtension extends AbstractClientConnector
implements Extension {
private boolean previouslyAttached = false;
protected Class<? extends ClientConnector> getAcceptedParentType() {
return ClientConnector.class;
}
protected void extend(AbstractClientConnector target) {
target.addExtension(this);
}
protected void removeFromTarget() {
getParent().removeExtension(this);
}
@Override
public void setParent(ClientConnector parent) {
if (previouslyAttached && parent != null) {
throw new IllegalStateException(
"An extension can not be set to extend a new target after getting detached from the previous.");
}
Class<? extends ClientConnector> acceptedParentType = getAcceptedParentType();
if (parent == null || acceptedParentType.isInstance(parent)) {
super.setParent(parent);
previouslyAttached = true;
} else {
throw new IllegalArgumentException(getClass().getName()
+ " can only be attached to targets of type "
+ acceptedParentType.getName() + " but attach to "
+ parent.getClass().getName() + " was attempted.");
}
}
}
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