letteroperation.java

简单的计算器程序

package calculate.operations;

import calculate.Calculate;
import calculate.Operation;

public class LetterOperation implements Operation {

	private String letter = "";
	
	public LetterOperation(String letter) {
		this.letter = letter;
	}

	public String getLetter() {
		return letter;
	}

	public void setLetter(String letter) {
		this.letter = letter;
	}

	public final void execute(Calculate calculate) {
		if (!"".equals(calculate.getLastInput()) && Operation.OPERATIONS.indexOf(calculate.getLastInput()) >= 0) {
			calculate.setShowText(Calculate.DEFAULT_SHOW_TEXT);
			calculate.setFloat(false);
		}

		if (Operation.POINT_OPERATION.equals(this.getLetter())) {
			calculate.setFloat(true);
			return;
		}

		String showText = calculate.getShowText();
		if (calculate.isFloat()) {
			calculate.setShowText(showText + this.getLetter());
		} else {
			if (Calculate.DEFAULT_SHOW_TEXT.equals(showText)) {
				if (!"0".equals(this.getLetter())) {
					calculate.setShowText(this.getLetter() + ".");
				}
				
				return;
			}
			
			calculate.setShowText(showText.substring(0, showText.length() - 1)
					+ this.getLetter() + ".");
		}
	}
}