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/*
// Licensed to Julian Hyde under one or more contributor license
// agreements. See the NOTICE file distributed with this work for
// additional information regarding copyright ownership.
//
// Julian Hyde licenses this file to you under the Apache License,
// Version 2.0 (the "License"); you may not use this file except in
// compliance with the License. You may obtain a copy of the License at:
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/
package org.eigenbase.xom;
import java.util.*;
/**
* StringEscaper is a utility for replacing special characters
* with escape sequences in strings. Initially, a StringEscaper starts out as
* an identity transform in the "mutable" state. Call defineEscape as many
* times as necessary to set up mappings, and then call makeImmutable() before
* using appendEscapedString to actually apply the defined transform. Or, use one of
* the global mappings pre-defined here.
*/
public class StringEscaper implements Cloneable
{
private ArrayList translationVector;
private String [] translationTable;
public static StringEscaper xmlEscaper;
public static StringEscaper xmlNumericEscaper;
public static StringEscaper htmlEscaper;
public static StringEscaper urlArgEscaper;
public static StringEscaper urlEscaper;
/**
* Identity transform
*/
public StringEscaper()
{
translationVector = new ArrayList();
}
/**
* Map character "from" to escape sequence "to"
*/
public void defineEscape(char from,String to)
{
int i = (int) from;
if (i >= translationVector.size()) {
// Extend list by adding the requisite number of nulls.
final int count = i + 1 - translationVector.size();
translationVector.addAll(
new AbstractList() {
public Object get(int index) {
return null;
}
public int size() {
return count;
}
});
}
translationVector.set(i, to);
}
/**
* Call this before attempting to escape strings; after this,
* defineEscape may not be called again.
*/
public void makeImmutable()
{
translationTable =
(String[]) translationVector.toArray(
new String[translationVector.size()]);
translationVector = null;
}
/**
* Apply an immutable transformation to the given string.
*/
public String escapeString(String s)
{
StringBuffer sb = null;
int n = s.length();
for (int i = 0; i < n; i++) {
char c = s.charAt(i);
String escape;
// codes >= 128 (e.g. Euro sign) are always escaped
if (c > 127) {
escape = "&#" + Integer.toString(c) + ";";
} else if (c >= translationTable.length) {
escape = null;
} else {
escape = translationTable[c];
}
if (escape == null) {
if (sb != null) {
sb.append(c);
}
} else {
if (sb == null) {
sb = new StringBuffer(n * 2);
sb.append(s.substring(0, i));
}
sb.append(escape);
}
}
if (sb == null) {
return s;
} else {
return sb.toString();
}
}
/**
* Apply an immutable transformation to the given string, writing the
* results to a string buffer.
*/
public void appendEscapedString(String s, StringBuffer sb)
{
int n = s.length();
for (int i = 0; i < n; i++) {
char c = s.charAt(i);
String escape;
if (c >= translationTable.length) {
escape = null;
} else {
escape = translationTable[c];
}
if (escape == null) {
sb.append(c);
} else {
sb.append(escape);
}
}
}
protected Object clone()
{
StringEscaper clone = new StringEscaper();
if (translationVector != null) {
clone.translationVector = new ArrayList(translationVector);
}
if (translationTable != null) {
clone.translationTable = (String[]) translationTable.clone();
}
return clone;
}
/**
* Create a mutable escaper from an existing escaper, which may
* already be immutable.
*/
public StringEscaper getMutableClone()
{
StringEscaper clone = (StringEscaper) clone();
if (clone.translationVector == null) {
clone.translationVector =
new ArrayList(Arrays.asList(clone.translationTable));
clone.translationTable = null;
}
return clone;
}
static
{
htmlEscaper = new StringEscaper();
htmlEscaper.defineEscape('&', "&");
htmlEscaper.defineEscape('"', """);
// htmlEscaper.defineEscape('\'',"'");
htmlEscaper.defineEscape('\'', "'");
htmlEscaper.defineEscape('<', "<");
htmlEscaper.defineEscape('>', ">");
xmlNumericEscaper = new StringEscaper();
xmlNumericEscaper.defineEscape('&',"&");
xmlNumericEscaper.defineEscape('"',""");
xmlNumericEscaper.defineEscape('\'',"'");
xmlNumericEscaper.defineEscape('<',"<");
xmlNumericEscaper.defineEscape('>',">");
urlArgEscaper = new StringEscaper();
urlArgEscaper.defineEscape('?', "%3f");
urlArgEscaper.defineEscape('&', "%26");
urlEscaper = urlArgEscaper.getMutableClone();
urlEscaper.defineEscape('%', "%%");
urlEscaper.defineEscape('"', "%22");
urlEscaper.defineEscape('\r', "+");
urlEscaper.defineEscape('\n', "+");
urlEscaper.defineEscape(' ', "+");
urlEscaper.defineEscape('#', "%23");
htmlEscaper.makeImmutable();
xmlEscaper = htmlEscaper;
xmlNumericEscaper.makeImmutable();
urlArgEscaper.makeImmutable();
urlEscaper.makeImmutable();
}
}
// End StringEscaper.java