samplexydataset.java

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package line;

import org.jfree.data.general.DatasetChangeEvent;
import org.jfree.data.xy.AbstractXYDataset;
import org.jfree.data.xy.XYDataset;

/**
 * XYDataset接口的实现类，该类获得一个正弦或余弦的数据集.
 */
public class SampleXYDataset extends AbstractXYDataset implements XYDataset {

	private double translate;

	public SampleXYDataset() {
		translate = 0.0D;
	}

	public double getTranslate() {
		return translate;
	}

	public void setTranslate(double d) {
		translate = d;
		notifyListeners(new DatasetChangeEvent(this, this));
	}

	public Number getX(int i, int j) {
		return new Double(-10D + translate + (double) j / 10D);
	}

	public Number getY(int i, int j) {
		if (i == 0)
			return new Double(Math.cos(-10D + translate + (double) j / 10D));
		else
			return new Double(2D * Math
					.sin(-10D + translate + (double) j / 10D));
	}

	public int getSeriesCount() {
		return 2;
	}

	public Comparable getSeriesKey(int i) {
		if (i == 0)
			return "y = cosine(x)";
		if (i == 1)
			return "y = 2*sine(x)";
		else
			return "Error";
	}

	public int getItemCount(int i) {
		return 200;
	}
}