StringEditor.java

package jp.dip.poketo7878;

/**
 * Created by masato on 2014/05/24.
 */
public class StringEditor {
    private String str;
    public Edit[] edits;

    public StringEditor(String sr) {
        this.str = sr;
        this.edits = new Edit[this.str.length()];
        for(int i = 0; i < this.str.length(); i++) {
            this.edits[i] = new Edit(this.str.substring(i,i+1));
        }
    }

    /*
     * 全てのインデックスは文字と文字の間の位置を指す
     */

    //idx文字目の後ろに追加
    public void insert(String s, int idx) {
        this.edits[idx].insert += s;
    }

    //from文字目からto文字目をstringで置換
    public void replace(String s, int from, int to) {
        //文字列のほうが長い場合
        if(s.length() > Math.abs(to - from + 1)) {
            //まずは範囲の文字を置換
            for(int i = from; i <= to; i++) {
                this.edits[i].rep = (s.charAt(i - from) + "");
            }
            //そして範囲の最後の文字に残りの文字をappendすることにする
            this.edits[to].append += s.substring(Math.abs(to - from) + 1);
        } else {
            //文字列が同じ長さか、文字列のほうが身近い場合
            //まずは文字列の長さ分置換していく
            for(int i = 0; i < s.length(); i++) {
                this.edits[i + from].rep = (s.charAt(i) + "");
            }
            //残りの範囲に削除マークを付ける
            for(int j = 1; j <= (Math.abs(to - from) - s.length()); j++) {
                this.edits[to + 1].deleted = true;
            }
        }
    }

    //idx文字目の後に追加
    public void append(String s, int idx) {
        this.edits[idx].append = s + this.edits[idx].append;
    }

    //idx文字目を削除
    public void delete(int idx) {
        this.edits[idx].deleted = true;
    }

    //from文字目からto文字目を削除
    public void delete(int from, int to) {
        for(int i = from; i <= to; i++) {
            this.edits[i].deleted = true;
        }
    }


    public String toString() {
        String s = "";
        for(int i = 0; i < this.str.length(); i++) {
            Edit e = edits[i];
            s += e.toString();
        }
        return s;
    }

    public static void main(String[] args) {
       String base = "0 1 2 3 4 5 6 7 8";
       StringEditor se = new StringEditor(base);
        se.replace("vi", 6,6);
        System.out.println(se.toString());
        for(Edit e: se.edits) {
            System.out.println(e.infoString());
        }
        se.append("Hoge",6);
        System.out.println(se.toString());
        for(Edit e: se.edits) {
            System.out.println(e.infoString());
        }
        se.insert("Moge",6);
        System.out.println(se.toString());
        for(Edit e: se.edits) {
            System.out.println(e.infoString());
        }
    }
}

class Edit {
    private String base;
    public boolean deleted;
    public String append = "";
    public String insert = "";
    public String rep = null;

    public Edit(String base) {
        this.base = base;
    }

    @Override
    public String toString() {
        String b = null;
        if(deleted) {
            b = "";
        } else if(rep != null) {
            b = rep;
        } else {
            b = base;
        }

        return (insert + b + append);
    }

    public String infoString() {
        String b = null;
        if(deleted) {
            b = "";
        } else if(rep != null) {
            b = rep;
        } else {
            b = base;
        }
        return "{insert: " + insert + ", b: " + b + ", append: " + append + "}";
    }
}