Perforce JViews Charts Sample: Stock Viewer

Description

This sample allows you to display the stock quotes of one or several companies, as well as several technical market indicators. Two kinds of charts are used to display the stock data:

The upper chart, which displays the stock data of the company being analyzed. Several other companies can be displayed in overlay,as well as indicators such as moving averages.
Two lower charts, each of them displaying one technical indicator (Volume, RSI,MACD, and so on).

A wide variety of interactions allow you to zoom and pan the visible time frame. You can also highlight the data by setting lower and upper price limits, or use a fisheye view that focuses on a specific time interval.

How to Use the Sample

Obtaining an API Key

In order to retrieve stock information from the Barchart web site, you must first register for a free API key. Visit: https://www.barchart.com/ondemand/free-market-data-api to generate your key, then use the Authentication menu to make it known to this sample.

Loading Quotes

The loading of quotes is specified by the controls available in the query panel:

The primary symbol field lets you specify the company ticker symbol.
The secondary symbols field lets you optionally specify a comma-separated list of symbols that will be plotted against the primary symbol.
The duration combo box lets you choose the time span for the query.
The frequency combo box lets you choose the frequency of the data. Two choices are available: Daily and Weekly.

Quotes are automatically loaded when the duration or the frequency of the query are modified. However, an explicit reload request must be made after changing the ticker symbols. To request an explicit reload of the stock data, press the

toolbar button.

The left scale of the upper chart displays the stock price. When a single symbol is selected, a secondary y-scale is displayed at the right-hand side of the chart. This scale displays the percentage variation of the stock price according to the first quote in the current time period. A dashed grid line is also drawn to locate the reference price.

Using Technical Indicators

The Indicators menu lets you specify the technical indicators that must be displayed by the charts. These indicators are split into two categories:

The upper indicators are drawn within the chart displaying the stock quotes. You can add as many indicators as you want through the Upper Indicators sub-menu.
The lower indicators are drawn in the lower charts. Each chart can display only one indicator. A submenu is available for each of these charts and lets you choose the indicator that must be displayed (Volume, MACD,RSI, and so on).

Controlling the visible range

Interactors

A Zoom interactor is set by default on the upper chart. To perform a zoom, simply click on the left mouse button and drag the mouse over the desired time interval. During the interaction, the y-range of the zoomed data window is automatically computed so that it contains all the data displayed within the specified time frame.

You can also perform a zoom by clicking with the left mouse button on the x-scale and dragging over the desired period. The selected time interval will automatically snap to the steps of the scale.

A Pan interactor is also set by default on all the charts. With this interactor, you can pan along the x-axis with the right mouse button.

Note: All these interactions are disabled when a local zoom is set.

The Zoom History

Whenever a zoom is performed, the previous zoom level is stored in the zoom history. You can browse the zoom history with the following toolbar buttons:

	To go back to the previous zoom level.
	To move forward to the next zoom level.
	To fit the zoom level to the chart contents, and reset the zoom history.

Using the Local Zoom

This special feature of Perforce JViews Charts lets you define a zoom on a local area of a chart. In the demonstration, you can specify a zoom factor for a given time interval. Using this mechanism, you can focus on a data subset while keeping an overview of the remaining values. The following toolbar buttons can be used to control the local zoom:

	Lets you activate or deactivate the local zoom.
	Increases the zooming factor within the local area.
	Decreases the zooming factor within the local area.

In addition to these controls, two dedicated interactors are set on the chart. These interactors let you change the zoomed area in the following ways:

Press the right mouse button within the local zoom area, and drag the mouse to translate it.
Press the left mouse button on one of the borders of the area, and drag the mouse to enlarge or shrink the area.

Note: All the operations affecting the visible range of the chart are disabled when the local zoom is set.

Using Threshold Lines

Threshold lines let you specify upper and lower price limits within the main chart. You can activate and deactivate the threshold lines with the

toolbar button.

The threshold limits can be edited with the range slider located in the toolbar (this slider only appears when threshold lines are used).

When threshold lines are activated, the rendering style of the data points depends on their price value:

A green color is used for values above the upper limit.
A red color is used for values below the lower limit.
An orange color is used for values between the two limits.

Controlling Display Properties

The following properties are accessible through the Display menu:

The Overview Representation submenu lets you choose the chart representation of the primary symbol when it is inoverview mode. This mode is set when the visible time range exceeds a duration of approximately three months for daily data, and approximately one year for weekly data. Four representation types are available: Line, Area, Stair, andBar.
The Detailed Representation submenu lets you choose the chart representation of the primary symbol when it is indetailed mode. This mode is set when the visible time range is below the limits mentioned above. Two representation types are available: Candle and HLOC (High-Low-Open-Close).
The Anti-aliasing item lets you toggle anti-aliased drawing for all the charts.
The Logarithmic Price Axis item lets you specify whether the y-scale of the quote chart is logarithmic or linear.

How to Run the Sample as an Application

This sample can be run as an application. The installation directory contains an executable JAR file, stock.jar, that allows you to execute the sample with a double click from a file browser. Note that if you are using Internet Explorer, you can open the installation directory and execute the JAR file from the browser. This technique may not work in other Web browsers.

Alternatively, you can run the sample application from the command line. First check that the Ant utility is properly configured. If not, see the instructions on how to configure Ant for Perforce JViews.

Then, go to the installation directory of the sample and type:

ant run

Topics Covered

Synchronization of several data sets using listeners.
Customization of the style computed by a rendering hint by subclassing the IlvGradientRenderingHint class.
Axis sharing.

Detailed Description

The sample loads stock information from barchart.com and displays it in charts on which you can perform interactions. The data is retrieved by sending a formatted query to the Barchart web site and decoding the result using a custom IlvDataReader object (instance of CSVDataReader). This reader extracts the data from the input stream and initializes the data source with the corresponding data sets.

In addition to the stock prices and volume information, several technical indicators can also be visualized. These technical indicators are handled through specialized datasets (instances of IlvDataSet custom implementation) and data source (instances of IlvDataSource custom implementations) objects.

The quotes are displayed through two different kinds of renderers, depending on the zoom level: either as a polyline chart or as a hilo chart. The zoom level checking is performed through an axis listener that monitors axis range changes: each time the x-axis visible range of the quote chart changes, the visibility of the hilo and polyline renderers is toggled accordingly. To zoom only part of the chart, a local zoom transformer can be set on the x-axis so that only data within the specified interval is zoomed, without changing the current visible range. To have a visual feedback of the zoomed area, several decorations and annotations can be associated to this local zoom. These decorations are handled by a dedicated class (LocalZoomHandler) that installs indicators (IlvDataIndicator) to visualize the extent of the zoomed area as well as scale annotation (IlvScaleAnnotation) to show the zoomed area bounds in the scale.

There are two kind of zoom interactions on the upper chart:

by means of a subclass of IlvChartZoomInteractor that modifies the dragged area so that the resulting zoomed area includes all the data contained within the selected time interval
by means of a subclass of IlvChartInteractor that handles interactions on the scale itself, to be able to zoom in a given time interval (the selection of this interval being done step-by-step according to the scale steps definition).

Threshold lines let you specify upper and lower price limits within the main chart, to change the rendering style of the stock price curves accordingly. The Threshold lines are implementation of IlvDataRenderingHint and are rendered through IlvDataIndicators and IlvScaleAnnotations objects.

Installation Directory

The Stock Viewer sample is installed here.