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/*
* Leaf.java 1.0
*
* This subclass of symbol represents (at least) terminal symbols returned
* by the scanner and placed on the parse stack. At present, this
* class does nothing more than its super class.
*
* Jun 11, 1997
*
* @see io.devnulllabs.openjava.ptree.ParseTree
* @see io.devnulllabs.openjava.ptree.ParseTreeObject
* @version 1.0 last updated: Jun 11, 1997
* @author Michiaki Tatsubori
*/
package io.devnulllabs.openjava.ptree;
import io.devnulllabs.openjava.ptree.util.ParseTreeVisitor;
/**
* The Leaf class is a token-node in the parse tree of OpenJava.
* Any object of this class or subclasses must be immutable.
*
* @see io.devnulllabs.openjava.ptree.ParseTree
* @see io.devnulllabs.openjava.ptree.NonLeaf
*/
public class Leaf extends ParseTreeObject implements ParseTree {
protected void replaceChildWith(ParseTree dist, ParseTree replacement)
throws ParseTreeException {
throw new ParseTreeException("no child");
}
/** textString is the text of this token. */
private String textString = null;
/** tokenID is the identifer number of this token */
private int tokenID = 0;
/** line is the number of the line at which this token is. */
public int line = -1;
/** charBegin is the number of the character at which this token is. */
public int charBegin = -1;
/**
* Allocates a new leaf(token) with its text.
*
* @param term_num dummy parameter.
* @param str its text.
*/
public Leaf(String str) {
this(-1, str, -1, -1);
}
/**
* Allocates a new leaf(token) with its text.
*
* @param term_num dummy parameter.
* @param str its text.
*/
public Leaf(int term_num, String str) {
this(term_num, str, -1, -1);
}
/**
* Allocates a new leaf(token) with its text and where this is.
*
* @param term_num dummy parameter.
* @param str its text.
*/
public Leaf(int term_num, String str, int line, int charBegin) {
tokenID = term_num;
textString = str;
this.line = line;
this.charBegin = charBegin;
}
/**
* Overrides to return its text as the string of this instance.
*
* @return the text of this token.
*/
public String toString() {
return textString;
}
/**
* Makes a new copy of this leaf-node.
* This method equals to makeCopy().
*
* @return the copy of this nonleaf-node as a ptree-node.
*/
public ParseTree makeRecursiveCopy() {
return (ParseTree) this.clone();
}
/**
* Makes a new copy of this leaf-node.
*
* @return the copy of this nonleaf-node as a ptree-node.
*/
public ParseTree makeCopy() {
return (ParseTree) this.clone();
}
/**
* Tests if the specified ptree-node equals to this leaf-node.
*
* @param p the ptree-node to be tested.
* @return true if p equals to this leaf-node
*/
public boolean equals(ParseTree p) {
if (p == null || !(p instanceof Leaf))
return false;
if (this == p)
return true;
return this.toString().equals(p.toString());
}
/**
* Tests if the specified string equals to this leaf-node's text.
*
* @param p the ptree-node to be tested.
* @return true if p equals to this leaf-node
*/
public boolean equals(String str) {
if (str == null)
return false;
return this.toString().equals(str);
}
/**
* Returns the identifer-number of this token.
*
* @return the identifer-number of this token.
*/
public int getTokenID() {
return tokenID;
}
/**
* Accepts a <code>ParseTreeVisitor</code> object as the role of a
* Visitor in the Visitor pattern, as the role of an Element in the
* Visitor pattern.<p>
*
* This invoke an appropriate <code>visit()</code> method on each
* child <code>ParseTree</code> object with this visitor.
*
* @param visitor a visitor
**/
public void childrenAccept(ParseTreeVisitor visitor) {
return;
}
public void accept(ParseTreeVisitor v) throws ParseTreeException {
v.visit(this);
}
}
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