org.rstudio.core.client.widget.HeaderBreaksItemCodec.java Source code

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Here is the source code for org.rstudio.core.client.widget.HeaderBreaksItemCodec.java

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/*
 * HeaderBreaksItemCodec.java
 *
 * Copyright (C) 2009-12 by RStudio, Inc.
 *
 * Unless you have received this program directly from RStudio pursuant
 * to the terms of a commercial license agreement with RStudio, then
 * this program is licensed to you under the terms of version 3 of the
 * GNU Affero General Public License. This program is distributed WITHOUT
 * ANY EXPRESS OR IMPLIED WARRANTY, INCLUDING THOSE OF NON-INFRINGEMENT,
 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Please refer to the
 * AGPL (http://www.gnu.org/licenses/agpl-3.0.txt) for more details.
 *
 */
package org.rstudio.core.client.widget;

import com.google.gwt.dom.client.*;
import org.rstudio.core.client.widget.FastSelectTable.ItemCodec;

/**
 * Provides plumbing for item codecs that may introduce non-value "header"
 * rows based on differences between two rows.
 */
public abstract class HeaderBreaksItemCodec<T, TItemOutput, TItemOutput2>
        implements ItemCodec<T, TItemOutput, TItemOutput2> {
    /**
     * Returns true if there should be a break introduced for "row".
     */
    protected abstract boolean needsBreak(TableRowElement prevRow, TableRowElement row);

    /**
     * Add a break for the given row. (This probably means adding a new row above
     * the given row.)
     * @param row The row for which a new break should be introduced.
     * @return Return the number of extra (non-value) rows just introduced.
     *    Make sure that your implementation of isValueRow returns false for
     *    any rows you introduce!
     */
    protected abstract int addBreak(TableRowElement row);

    public void onRowsChanged(TableSectionElement tbody) {
        if (!hasNonValueRows())
            return;

        TableRowElement lastRow = null;

        Node previousSibling = tbody.getPreviousSibling();
        if (previousSibling != null && previousSibling.getNodeType() == Node.ELEMENT_NODE
                && ((Element) previousSibling).getTagName().equalsIgnoreCase("tbody")) {
            TableSectionElement prevbody = (TableSectionElement) previousSibling;
            NodeList<TableRowElement> prevrows = prevbody.getRows();
            if (prevrows.getLength() > 0) {
                TableRowElement lastRowEl = prevrows.getItem(prevrows.getLength() - 1);
                if (isValueRow(lastRowEl)) {
                    lastRow = lastRowEl;
                }
            }
        }

        int totalExtraRows = 0;
        final NodeList<TableRowElement> rows = tbody.getRows();
        for (int i = 0; i < rows.getLength(); i++) {
            TableRowElement row = rows.getItem(i);
            if (needsBreak(lastRow, row)) {
                int extraRows = addBreak(row);
                i += extraRows;
                totalExtraRows += extraRows;
            }

            lastRow = row;
        }

        tbody.setPropertyInt(EXTRA_ROWS, totalExtraRows);
    }

    public Integer logicalOffsetToPhysicalOffset(TableElement table, int offset) {
        if (!hasNonValueRows())
            return offset;

        NodeList<TableSectionElement> bodies = table.getTBodies();
        int skew = 0;
        int pos = 0;
        for (int i = 0; i < bodies.getLength(); i++) {
            TableSectionElement body = bodies.getItem(i);
            NodeList<TableRowElement> rows = body.getRows();
            int rowCount = rows.getLength();
            int extraRows = body.getPropertyInt(EXTRA_ROWS);
            int max = (pos - skew) + (rowCount - extraRows);
            if (max <= offset) {
                // It's safe to skip this whole tbody. These are not the
                // rows we're looking for.
                pos += rowCount;
                skew += extraRows;
            } else {
                NodeList<TableRowElement> allRows = table.getRows();
                for (; pos < allRows.getLength(); pos++) {
                    TableRowElement row = allRows.getItem(pos);
                    if (!isValueRow(row))
                        skew++;
                    else if (offset == (pos - skew))
                        return pos;
                }
            }
        }

        if (pos - skew == offset)
            return pos;
        else
            return null;
    }

    public Integer physicalOffsetToLogicalOffset(TableElement table, int offset) {
        if (!hasNonValueRows())
            return offset;

        if (offset >= table.getRows().getLength())
            return null;

        NodeList<TableSectionElement> bodies = table.getTBodies();
        int logicalOffset = 0;
        for (int i = 0; offset > 0 && i < bodies.getLength(); i++) {
            TableSectionElement body = bodies.getItem(i);
            NodeList<TableRowElement> rows = body.getRows();
            int rowCount = rows.getLength();
            int extraRows = body.getPropertyInt(EXTRA_ROWS);
            if (rowCount < offset) {
                logicalOffset += rowCount - extraRows;
                offset -= rowCount;
            } else {
                // It's in here
                for (int j = 0; offset > 0 && j < rows.getLength(); j++) {
                    offset--;
                    if (isValueRow(rows.getItem(j)))
                        logicalOffset++;
                }
            }
        }

        return logicalOffset;
    }

    public int getLogicalRowCount(TableElement table) {
        if (!hasNonValueRows())
            return table.getRows().getLength();

        NodeList<TableSectionElement> bodies = table.getTBodies();
        int logicalOffset = 0;
        for (int i = 0; i < bodies.getLength(); i++) {
            TableSectionElement body = bodies.getItem(i);
            NodeList<TableRowElement> rows = body.getRows();
            int rowCount = rows.getLength();
            int extraRows = body.getPropertyInt(EXTRA_ROWS);
            logicalOffset += rowCount - extraRows;
        }
        return logicalOffset;
    }

    private static final String EXTRA_ROWS = "extrarows";
}