优先考虑组成而不是继承。
解决方案考虑到可能还有另一种类型的单词可能需要WordLengthSupport。
类似地，可以创建和实现其他接口，并且各种单词类型可以具有这些接口的混合和匹配。
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public class WordLength { private int length = 0; public int getLength(){return length}; public void setLength(int length){this.length = length};}。
public interface WordLengthSupport { public WordLength getWordLength();}。
public class BetterWord extends AbstractWord implements WordLengthSupport { WordLength wordLength; public WordLength getWordLength() { if(wordLength==null) { // each time word changes // make sure to set wordLength to null calculateWordLength(); } return wordLength; } private void calculateWordLength() { // This method should be // called in constructor // or each time word changes int length = // based on the variable word calculate Length.. this.wordLength = new WordLength(); this.wordLength.setLength(length); }}。
public class BetterWordDescriptor extends AbstractWord implements WordLengthSupport { WordLength wordLength; public WordLength getWordLength(return wordLength); public void setWordLength(WordLength wordLength) { // Use this to populate WordLength of respective word this.wordLength = wordLength; }}。
策略模式定义 了一系列算法，将每个算法封装在一起，并使它们可互换。策略使算法独立于使用该算法的客户端而变化。
该解决方案不使用策略模式，但可以对其进行重构。
