Java String Unescape unescape(String str)

Description

unescape

License

Apache License

Declaration

public static String unescape(String str) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

public class Main {
    public static String unescape(String str) {
        int idxS = str.indexOf('&');
        if (idxS < 0) {
            return str;
        }//from  ww  w .  j  a v a 2s  . co m
        StringBuilder sb = new StringBuilder(str.length());
        int idxE, idx, size;
        char c;
        int prev = 0;
        while (idxS != -1) {
            if (prev < idxS) {
                sb.append(str.substring(prev, idxS));
                prev = idxS;
            }
            idxE = str.indexOf(';', idxS);
            if (idxE < 0) {
                break;
            }
            idx = idxS + 1;
            size = idxE - idxS - 1;
            if (size < 2) {
                sb.append(str.substring(idxS, idxE + 1));
            } else {
                c = str.charAt(idx);
                switch (c) {
                case 'l':
                    if (!xmlDecodeLT(str, idx, sb, size)) {
                        sb.append("&");
                        idxE = idxS;
                    }
                    break;

                case 'g':
                    if (!xmlDecodeGT(str, idx, sb, size)) {
                        sb.append("&");
                        idxE = idxS;
                    }
                    break;

                case 'q':
                    if (!xmlDecodeQUOT(str, idx, sb, size)) {
                        sb.append("&");
                        idxE = idxS;
                    }
                    break;

                case 'a':
                    if (!xmlDecodeAMPAPOS(str, idx, sb, size)) {
                        sb.append("&");
                        idxE = idxS;
                    }
                    break;

                case 'n':
                    if (!xmlDecodeNBSP(str, idx, sb, size)) {
                        sb.append("&");
                        idxE = idxS;
                    }
                    break;

                case '#':
                    if (!xmlDecodeNumber(str, idx, sb, idxE)) {
                        sb.append("&");
                        idxE = idxS;
                    }
                    break;

                default:
                    sb.append("&");
                    idxE = idxS;
                }
            }
            prev = idxE + 1;
            idxS = str.indexOf('&', prev);
        }
        if (prev < str.length()) {
            sb.append(str.substring(prev));
        }
        return sb.toString();
    }

    private static boolean xmlDecodeLT(String str, int idx, StringBuilder sb, int size) {
        boolean isRecognized = true;
        char c = str.charAt(idx + 1);
        if ((size != 2) || (c != 't')) {
            isRecognized = false;
        } else {
            // lt
            sb.append('<');
        }
        return isRecognized;
    }

    private static boolean xmlDecodeGT(String str, int idx, StringBuilder sb, int size) {
        boolean isRecognized = true;
        char c = str.charAt(idx + 1);
        if ((size != 2) || (c != 't')) {
            isRecognized = false;
        } else {
            sb.append('>');
        }
        return isRecognized;
    }

    private static boolean xmlDecodeQUOT(String str, int idx, StringBuilder sb, int size) {
        boolean isRecognized = true;
        char c = str.charAt(idx + 1);
        if ((size != 4) || (c != 'u' || str.charAt(idx + 2) != 'o' || str.charAt(idx + 3) != 't')) {
            isRecognized = false;
        } else {
            sb.append('"');
        }
        return isRecognized;
    }

    private static boolean xmlDecodeAMPAPOS(String str, int idx, StringBuilder sb, int size) {
        boolean isRecognized = true;
        char c = str.charAt(idx + 1);
        if ((size == 3) && (c == 'm') && (str.charAt(idx + 2) == 'p')) {
            sb.append('&');
        } else if ((size == 4) && (c == 'p') && (str.charAt(idx + 2) == 'o') && (str.charAt(idx + 3) == 's')) {
            sb.append('\'');
        } else {
            isRecognized = false;
        }
        return isRecognized;
    }

    private static boolean xmlDecodeNBSP(String str, int idx, StringBuilder sb, int size) {
        boolean isRecognized = true;
        char c = str.charAt(idx + 1);
        if ((size != 4) || (c != 'b' || str.charAt(idx + 2) != 's' || str.charAt(idx + 3) != 'p')) {
            isRecognized = false;
        } else {
            sb.append(' ');
        }
        return isRecognized;
    }

    private static boolean xmlDecodeNumber(String str, int idx, StringBuilder sb, int idxE) {
        boolean isRecognized = true;
        try {
            char c;
            char c1 = str.charAt(idx + 1);
            if (c1 == 'x') {
                c = (char) Integer.parseInt(str.substring(idx + 2, idxE), 16);
            } else {
                c = (char) Integer.parseInt(str.substring(idx + 1, idxE));
            }
            sb.append(c);
        } catch (NumberFormatException ex) {
            isRecognized = false;
        }
        return isRecognized;
    }
}

Related

1. unescape(String src)
2. unescape(String src)
3. unescape(String src)
4. unescape(String st)
5. unescape(String str)
6. unescape(String str)
7. unescape(String str)
8. unescape(String str)
9. unescape(String str)