/*
* Copyright 2000-2016 Vaadin Ltd.
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may not
* use this file except in compliance with the License. You may obtain a copy of
* the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations under
* the License.
*/
package com.vaadin.client.widget.escalator;
import java.util.List;
import com.google.gwt.dom.client.Style.Display;
import com.google.gwt.dom.client.Style.Unit;
import com.google.gwt.dom.client.TableCellElement;
import com.vaadin.client.widget.escalator.FlyweightRow.CellIterator;
import com.vaadin.client.widgets.Escalator;
/**
* A {@link FlyweightCell} represents a cell in the {@link Grid} or
* {@link Escalator} at a certain point in time.
*
* <p>
* Since the {@link FlyweightCell} follows the <code>Flyweight</code>-pattern
* any instance of this object is subject to change without the user knowing it
* and so should not be stored anywhere outside of the method providing these
* instances.
*
* @since 7.4
* @author Vaadin Ltd
*/
public class FlyweightCell {
public static final String COLSPAN_ATTR = "colSpan";
private final int column;
private final FlyweightRow row;
private TableCellElement element = null;
private CellIterator currentIterator = null;
public FlyweightCell(final FlyweightRow row, final int column) {
this.row = row;
this.column = column;
}
/**
* Returns the row index of the cell
*/
public int getRow() {
assertSetup();
return row.getRow();
}
/**
* Returns the column index of the cell
*/
public int getColumn() {
assertSetup();
return column;
}
/**
* Returns the element of the cell. Can be either a <code>TD</code> element
* or a <code>TH</code> element.
*/
public TableCellElement getElement() {
assertSetup();
return element;
}
/**
* Return the colspan attribute of the element of the cell.
*/
public int getColSpan() {
assertSetup();
return element.getPropertyInt(COLSPAN_ATTR);
}
/**
* Sets the DOM element for this FlyweightCell, either a <code>TD</code> or
* a <code>TH</code>. It is the caller's responsibility to actually insert
* the given element to the document when needed.
*
* @param element
* the element corresponding to this cell, cannot be null
*/
public void setElement(TableCellElement element) {
assert element != null;
assertSetup();
this.element = element;
}
void setup(final CellIterator iterator) {
currentIterator = iterator;
if (iterator.areCellsAttached()) {
final TableCellElement e = row.getElement().getCells()
.getItem(column);
assert e != null : "Cell " + column + " for logical row "
+ row.getRow() + " doesn't exist in the DOM!";
e.setPropertyInt(COLSPAN_ATTR, 1);
if (row.getColumnWidth(column) >= 0) {
e.getStyle().setWidth(row.getColumnWidth(column), Unit.PX);
}
e.getStyle().clearDisplay();
setElement(e);
}
}
/**
* Tear down the state of the Cell.
* <p>
* This is an internal check method, to prevent retrieving uninitialized
* data by calling {@link #getRow()}, {@link #getColumn()} or
* {@link #getElement()} at an improper time.
* <p>
* This should only be used with asserts ("
* <code>assert flyweightCell.teardown()</code> ") so that the code is never
* run when asserts aren't enabled.
*
* @return always <code>true</code>
* @see FlyweightRow#teardown()
*/
boolean teardown() {
currentIterator = null;
element = null;
return true;
}
/**
* Asserts that the flyweight cell has properly been set up before trying to
* access any of its data.
*/
private void assertSetup() {
assert currentIterator != null : "FlyweightCell was not properly "
+ "initialized. This is either a bug in Grid/Escalator "
+ "or a Cell reference has been stored and reused "
+ "inappropriately.";
}
public void setColSpan(final int numberOfCells) {
if (numberOfCells < 1) {
throw new IllegalArgumentException(
"Number of cells should be more than 0");
}
/*-
* This will default to 1 if unset, as per DOM specifications:
* http://www.w3.org/TR/html5/tabular-data.html#attributes-common-to-td-and-th-elements
*/
final int prevColSpan = getElement().getPropertyInt(COLSPAN_ATTR);
if (numberOfCells == 1 && prevColSpan == 1) {
return;
}
getElement().setPropertyInt(COLSPAN_ATTR, numberOfCells);
adjustCellWidthForSpan(numberOfCells);
hideOrRevealAdjacentCellElements(numberOfCells, prevColSpan);
currentIterator.setSkipNext(numberOfCells - 1);
}
private void adjustCellWidthForSpan(final int numberOfCells) {
final int cellsToTheRight = currentIterator
.rawPeekNext(numberOfCells - 1).size();
final double selfWidth = row.getColumnWidth(column);
double widthsOfColumnsToTheRight = 0;
for (int i = 0; i < cellsToTheRight; i++) {
widthsOfColumnsToTheRight += row.getColumnWidth(column + i + 1);
}
getElement().getStyle().setWidth(selfWidth + widthsOfColumnsToTheRight,
Unit.PX);
}
private void hideOrRevealAdjacentCellElements(final int numberOfCells,
final int prevColSpan) {
final int affectedCellsNumber = Math.max(prevColSpan, numberOfCells);
final List<FlyweightCell> affectedCells = currentIterator
.rawPeekNext(affectedCellsNumber - 1);
if (prevColSpan < numberOfCells) {
for (int i = 0; i < affectedCells.size(); i++) {
affectedCells.get(prevColSpan + i - 1).getElement().getStyle()
.setDisplay(Display.NONE);
}
} else if (prevColSpan > numberOfCells) {
for (int i = 0; i < affectedCells.size(); i++) {
affectedCells.get(numberOfCells + i - 1).getElement().getStyle()
.clearDisplay();
}
}
}
}