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I would use a boolean[65536] which flags if the character has to be escaped. I am quite confident that this is faster than the switch.

But only profiling can show if it is really faster.

String query = "http://This+*is||a&&test(whatever!!!!!!)";
char[] queryCharArray = new char[query.length()*2];
char c;
int length = query.length();
int currentIndex = 0;
for (int i = 0; i < length; i++) 
{
    c = query.charAt(i);
    if(mustBeEscaped[c]){        
        queryCharArray[currentIndex++] = '\\'; 
        queryCharArray[currentIndex++] = c; 
    }
    else if('&'==c || '|'==c){
        if(i+1 < length && query.charAt(i+1) == c){
            queryCharArray[currentIndex++] = '\\'; 
            queryCharArray[currentIndex++] = c; 
            queryCharArray[currentIndex++] = c; 
            i++;
        }
    }    
    else{
        queryCharArray[currentIndex++] = c;     
    }
}

query = new String(queryCharArray,0,currentIndex);

System.out.println("TEST="+query);

private static final boolean[] mustBeEscaped = new boolean[65536];
static{
mustBeEscaped[':']=  //
  for(char c: "\\?+-!(){}[]^\"~*".toCharArray()){
     mustBeEscaped[c]=true; 
  }
}

I would use a boolean[65536] which flags if the character has to be escaped. I am quite confident that this is faster than the switch.

But only profiling can show if it is really faster.

String query = "http://This+*is||a&&test(whatever!!!!!!)";
char[] queryCharArray = new char[query.length()*2];
char c;
int length = query.length();
int currentIndex = 0;
for (int i = 0; i < length; i++) 
{
    c = query.charAt(i);
    if(mustBeEscaped[c]){        
      if('&'==c || '|'==c){
        if(i+1 < length && query.charAt(i+1) == c){
            queryCharArray[currentIndex++] = '\\'; 
            queryCharArray[currentIndex++] = c; 
            queryCharArray[currentIndex++] = c; 
            i++;
        }
      }    
      else{
        queryCharArray[currentIndex++] = '\\'; 
        queryCharArray[currentIndex++] = c; 
      }     
    }
    else{
        queryCharArray[currentIndex++] = c;     
    }
}

query = new String(queryCharArray,0,currentIndex);

System.out.println("TEST="+query);

private static final boolean[] mustBeEscaped = new boolean[65536];
static{
mustBeEscaped[':']=  //
  for(char c: "\\?+-!(){}[]^\"~*&|".toCharArray()){
     mustBeEscaped[c]=true; 
  }
}

I would use a boolean[65536] which flags if the character has to be escaped. I am quite confident that this is faster than the switch.

But only profiling can show if it is really faster.

String query = "http://This+*is||a&&test(whatever!!!!!!)";
char[] queryCharArray = new char[query.length()*2];
char c;
int length = query.length();
int currentIndex = 0;
for (int i = 0; i < length; i++) 
{
    c = query.charAt(i);
    if(mustBeEscaped[c]){        
        queryCharArray[currentIndex++] = '\\'; 
        queryCharArray[currentIndex++] = c; 
    }
    else if('&'==c || '|'==c){
        if(i+1 < length && query.charAt(i+1) == c){
            queryCharArray[currentIndex++] = '\\'; 
            queryCharArray[currentIndex++] = c; 
            queryCharArray[currentIndex++] = c; 
            i++;
        }
    }    
    else{
        queryCharArray[currentIndex++] = c;     
    }
}

query = new String(queryCharArray,0,currentIndex);

System.out.println("TEST="+query);

private static final boolean mustBeEscaped[]= new boolean[65536];
static{
mustBeEscaped[':']=  //
     mustBeEscaped['\\']= //
     mustBeEscaped['?']= //
     mustBeEscaped['+']= //
     mustBeEscaped['-']= //
     mustBeEscaped['!']= //
     mustBeEscaped['(']= //
     mustBeEscaped[')']= //
     mustBeEscaped['{']= //
     mustBeEscaped['}']= //
     mustBeEscaped['[']= //
     mustBeEscaped[']']= //
     mustBeEscaped['^']= //
     mustBeEscaped['"']= //
     mustBeEscaped['~']= //
     mustBeEscaped['*']= true;
}

I would use a boolean[65536] which flags if the character has to be escaped. I am quite confident that this is faster than the switch.

But only profiling can show if it is really faster.

String query = "http://This+*is||a&&test(whatever!!!!!!)";
char[] queryCharArray = new char[query.length()*2];
char c;
int length = query.length();
int currentIndex = 0;
for (int i = 0; i < length; i++) 
{
    c = query.charAt(i);
    if(mustBeEscaped[c]){        
        queryCharArray[currentIndex++] = '\\'; 
        queryCharArray[currentIndex++] = c; 
    }
    else if('&'==c || '|'==c){
        if(i+1 < length && query.charAt(i+1) == c){
            queryCharArray[currentIndex++] = '\\'; 
            queryCharArray[currentIndex++] = c; 
            queryCharArray[currentIndex++] = c; 
            i++;
        }
    }    
    else{
        queryCharArray[currentIndex++] = c;     
    }
}

query = new String(queryCharArray,0,currentIndex);

System.out.println("TEST="+query);

private static final boolean[] mustBeEscaped = new boolean[65536];
static{
mustBeEscaped[':']=  //
  for(char c: "\\?+-!(){}[]^\"~*".toCharArray()){
     mustBeEscaped[c]=true; 
  }
}

I would use a boolean[65536] which flags if the character has to be escaped. I am quite confident that this is faster than the switch.

But only profiling can show if it is really faster.

I would use a boolean[65536] which flags if the character has to be escaped. I am quite confident that this is faster than the switch.

But only profiling can show if it is really faster.

String query = "http://This+*is||a&&test(whatever!!!!!!)";
char[] queryCharArray = new char[query.length()*2];
char c;
int length = query.length();
int currentIndex = 0;
for (int i = 0; i < length; i++) 
{
    c = query.charAt(i);
    if(mustBeEscaped[c]){        
        queryCharArray[currentIndex++] = '\\'; 
        queryCharArray[currentIndex++] = c; 
    }
    else if('&'==c || '|'==c){
        if(i+1 < length && query.charAt(i+1) == c){
            queryCharArray[currentIndex++] = '\\'; 
            queryCharArray[currentIndex++] = c; 
            queryCharArray[currentIndex++] = c; 
            i++;
        }
    }    
    else{
        queryCharArray[currentIndex++] = c;     
    }
}

query = new String(queryCharArray,0,currentIndex);

System.out.println("TEST="+query);

private static final boolean mustBeEscaped[]= new boolean[65536];
static{
mustBeEscaped[':']=  //
     mustBeEscaped['\\']= //
     mustBeEscaped['?']= //
     mustBeEscaped['+']= //
     mustBeEscaped['-']= //
     mustBeEscaped['!']= //
     mustBeEscaped['(']= //
     mustBeEscaped[')']= //
     mustBeEscaped['{']= //
     mustBeEscaped['}']= //
     mustBeEscaped['[']= //
     mustBeEscaped[']']= //
     mustBeEscaped['^']= //
     mustBeEscaped['"']= //
     mustBeEscaped['~']= //
     mustBeEscaped['*']= true;
}