com.google.gwt.gen2.table.client.MutableTableModel.java Source code

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Here is the source code for com.google.gwt.gen2.table.client.MutableTableModel.java

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/*
 * Copyright 2008 Google Inc.
 * 
 * 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.google.gwt.gen2.table.client;

import com.google.gwt.gen2.event.shared.HandlerRegistration;
import com.google.gwt.gen2.table.event.client.HasRowInsertionHandlers;
import com.google.gwt.gen2.table.event.client.HasRowRemovalHandlers;
import com.google.gwt.gen2.table.event.client.HasRowValueChangeHandlers;
import com.google.gwt.gen2.table.event.client.RowInsertionEvent;
import com.google.gwt.gen2.table.event.client.RowInsertionHandler;
import com.google.gwt.gen2.table.event.client.RowRemovalEvent;
import com.google.gwt.gen2.table.event.client.RowRemovalHandler;
import com.google.gwt.gen2.table.event.client.RowValueChangeEvent;
import com.google.gwt.gen2.table.event.client.RowValueChangeHandler;

/**
 * A mutable version of the {@link TableModel} that supports inserting and
 * removing rows and setting cell data.
 * 
 * @param <RowType> the data type of the row values
 */
public abstract class MutableTableModel<RowType> extends TableModel<RowType>
        implements HasRowInsertionHandlers, HasRowRemovalHandlers, HasRowValueChangeHandlers<RowType> {
    public HandlerRegistration addRowInsertionHandler(RowInsertionHandler handler) {
        return addHandler(RowInsertionEvent.TYPE, handler);
    }

    public HandlerRegistration addRowRemovalHandler(RowRemovalHandler handler) {
        return addHandler(RowRemovalEvent.TYPE, handler);
    }

    public HandlerRegistration addRowValueChangeHandler(RowValueChangeHandler<RowType> handler) {
        return addHandler(RowValueChangeEvent.TYPE, handler);
    }

    /**
     * Insert a row and increment the row count by one.
     * 
     * @param beforeRow the row index of the new row
     * TODO (jlabanca): should this require a row value?
     */
    public void insertRow(int beforeRow) {
        if (onRowInserted(beforeRow)) {
            // Fire listeners
            fireEvent(new RowInsertionEvent(beforeRow));

            // Increment the row count
            int numRows = getRowCount();
            if (numRows != UNKNOWN_ROW_COUNT) {
                setRowCount(numRows + 1);
            }
        }
    }

    /**
     * Remove a row and decrement the row count by one.
     * 
     * @param row the row index of the removed row
     */
    public void removeRow(int row) {
        if (onRowRemoved(row)) {
            // Fire listeners
            fireEvent(new RowRemovalEvent(row));

            // Decrement the row count
            int numRows = getRowCount();
            if (numRows != UNKNOWN_ROW_COUNT) {
                setRowCount(numRows - 1);
            }
        }
    }

    /**
     * Set a new row value.
     * 
     * @param row the row index
     * @param rowValue the new row value at this row
     */
    public void setRowValue(int row, RowType rowValue) {
        if (onSetRowValue(row, rowValue)) {
            // Fire the listeners
            fireEvent(new RowValueChangeEvent<RowType>(row, rowValue));

            // Update the row count
            int numRows = getRowCount();
            if (numRows != UNKNOWN_ROW_COUNT && row >= numRows) {
                setRowCount(row + 1);
            }
        }
    }

    /**
     * Event fired when a row is inserted. Returning true will increment the row
     * count by one.
     * 
     * @param beforeRow the row index of the new row
     * @return true if the action is successful
     */
    protected abstract boolean onRowInserted(int beforeRow);

    /**
     * Event fired when a row is removed. Returning true will decrement the row
     * count by one.
     * 
     * @param row the row index of the removed row
     * @return true if the action is successful
     */
    protected abstract boolean onRowRemoved(int row);

    /**
     * Event fired when the local data changes. Returning true will ensure that
     * the row count is at least as one greater than the row index.
     * 
     * @param row the row index
     * @param rowValue the new row value at this row
     * @return true if the action is successful
     */
    protected abstract boolean onSetRowValue(int row, RowType rowValue);
}