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/*
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* Copyright 2011-2012 GRNET S.A. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or
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* without modification, are permitted provided that the following
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* conditions are met:
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*
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* 1. Redistributions of source code must retain the above
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* copyright notice, this list of conditions and the following
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* disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials
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* provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* The views and conclusions contained in the software and
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* documentation are those of the authors and should not be
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* interpreted as representing official policies, either expressed
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* or implied, of GRNET S.A.
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*/
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package gr.grnet.pithos.web.client.components;
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import com.google.gwt.event.dom.client.ClickEvent;
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import com.google.gwt.event.dom.client.ClickHandler;
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import com.google.gwt.event.logical.shared.ValueChangeEvent;
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import com.google.gwt.event.logical.shared.ValueChangeHandler;
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import com.google.gwt.event.shared.HandlerRegistration;
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import com.google.gwt.user.client.DOM;
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import com.google.gwt.user.client.Element;
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import com.google.gwt.user.client.ui.FocusWidget;
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import com.google.gwt.user.client.ui.HasValue;
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/**
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* Checkbox with three states (checked, unchecked and undefined).
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*
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*/
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public class TristateCheckBox extends FocusWidget implements HasValue<Boolean> {
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private static final String UNCHECKED_IMG = "images/tristate_unchecked.gif";
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private static final String UNKNOWN_IMG = "images/tristate_intermediate.gif";
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private static final String CHECKED_IMG = "images/tristate_checked.gif";
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protected final Element buttonElement = DOM.createElement("input");
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private boolean valueChangeHandlerInitialized;
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private Boolean value;
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protected Boolean initialValue;
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public TristateCheckBox(final Boolean state) {
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DOM.setElementProperty(buttonElement, "type", "image");
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setElement(buttonElement);
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setStyleName("tristateCheckbox");
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DOM.setElementAttribute(buttonElement, "src", UNCHECKED_IMG);
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addClickHandler(new ClickHandler() {
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@Override
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public void onClick(ClickEvent event) {
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final String img = DOM.getElementAttribute(buttonElement, "src");
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String newImg;
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if (img.endsWith(UNCHECKED_IMG))
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newImg = CHECKED_IMG;
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else if (img.endsWith(UNKNOWN_IMG))
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newImg = UNCHECKED_IMG;
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else if (img.endsWith(CHECKED_IMG))
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if (initialValue==null) // Only show unknown choice if there is a reason for it
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newImg = UNKNOWN_IMG;
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else
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newImg = UNCHECKED_IMG;
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else
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throw new IllegalArgumentException("unknown checkbox state");
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DOM.setElementAttribute(buttonElement, "src", newImg);
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}
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});
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setState(state);
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initialValue = state;
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}
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public void setState(final Boolean state) {
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DOM.setElementAttribute(buttonElement, "src", state == null ?
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UNKNOWN_IMG : state.booleanValue() ? CHECKED_IMG : UNCHECKED_IMG);
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}
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public Boolean getState() {
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final String img = DOM.getElementAttribute(buttonElement, "src");
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if (img.endsWith(UNCHECKED_IMG))
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return Boolean.FALSE;
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else if (img.endsWith(UNKNOWN_IMG))
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return null;
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else if (img.endsWith(CHECKED_IMG))
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return Boolean.TRUE;
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else
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throw new IllegalArgumentException("unknown checkbox state");
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}
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@Override
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public Boolean getValue() {
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return value;
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}
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@Override
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public void setValue(final Boolean _value) {
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value = _value;
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}
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@Override
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public HandlerRegistration addValueChangeHandler(
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ValueChangeHandler<Boolean> handler) {
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// Is this the first value change handler? If so, time to add handlers
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if (!valueChangeHandlerInitialized) {
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ensureDomEventHandlers();
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valueChangeHandlerInitialized = true;
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}
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return addHandler(handler, ValueChangeEvent.getType());
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}
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protected void ensureDomEventHandlers() {
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addClickHandler(new ClickHandler() {
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@Override
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public void onClick(ClickEvent event) {
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ValueChangeEvent.fire(TristateCheckBox.this, getValue());
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}
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});
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}
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@Override
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public void setValue(Boolean _value, boolean fireEvents) {
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Boolean oldValue = getValue();
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setValue(_value);
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if (_value.equals(oldValue))
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return;
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if (fireEvents)
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ValueChangeEvent.fire(this, _value);
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}
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}
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