该原代码是实现机器学习中条件随机场模型的Java代码

				/**
				 * 
				 */
				package lcrf.logic;
				
				import java.io.Serializable;
				import java.util.List;
				import java.util.Vector;
				
				/**
				 * @author Bernd Gutmann
				 * 
				 */
				public class StringConstant implements Term, Serializable {
				    private static final long serialVersionUID = 3258411737761134385L;
				
				    private int type;
				
				    public int getType() {
				        return type;
				    }
				
				    public void setType(int type) {
				        this.type = type;
				    }
				
				    private String content;
				
				    private int hashCode;
				
				    private String stringrep;
				
				    public StringConstant(String content) {
				        this.content = content;
				        this.stringrep = '\'' + content + '\'';
				        this.hashCode = this.stringrep.hashCode();
				    }
				
				    public String toString() {
				        return this.stringrep;
				    }
				
				    public boolean equals(Object anObject) {
				        if (this == anObject) {
				            return true;
				        }
				        if (anObject instanceof StringConstant) {
				            return this.content.equals(((StringConstant) anObject).content);
				        }
				        return false;
				    }
				
				    public boolean hasSubterms() {
				        return false;
				    }
				
				    public boolean containsVariable(Variable v) {
				        return false;
				    }
				
				    public List getContainedVariables() {
				        return new Vector(0);
				    }
				
				    public StringConstant clone() {
				        return new StringConstant(content);
				    }
				
				    public int hashCode() {
				        return this.hashCode;
				    }
				
				    public boolean hasVariables() {
				        return false;
				    }
				
				}