StringBuffer based on char array
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, International
* Business Machines, Inc., http://www.apache.org. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
/**
* XMLString is a structure used to pass character arrays. However,
* XMLStringBuffer is a buffer in which characters can be appended
* and extends XMLString so that it can be passed to methods
* expecting an XMLString object. This is a safe operation because
* it is assumed that any callee will <strong>not</strong> modify
* the contents of the XMLString structure.
* <p>
* The contents of the string are managed by the string buffer. As
* characters are appended, the string buffer will grow as needed.
* <p>
* <strong>Note:</strong> Never set the <code>ch</code>,
* <code>offset</code>, and <code>length</code> fields directly.
* These fields are managed by the string buffer. In order to reset
* the buffer, call <code>clear()</code>.
*
* @author Andy Clark, IBM
* @author Eric Ye, IBM
*
* @version $Id: XMLStringBuffer.java 515 2008-03-17 21:02:23Z jfrederic.clere@jboss.com $
*/
public class XMLStringBuffer
extends XMLString {
//
// Constants
//
/** Default buffer size (32). */
public static final int DEFAULT_SIZE = 32;
//
// Constructors
//
/**
*
*/
public XMLStringBuffer() {
this(DEFAULT_SIZE);
} // <init>()
/**
*
*
* @param size
*/
public XMLStringBuffer(int size) {
ch = new char[size];
} // <init>(int)
/** Constructs a string buffer from a char. */
public XMLStringBuffer(char c) {
this(1);
append(c);
} // <init>(char)
/** Constructs a string buffer from a String. */
public XMLStringBuffer(String s) {
this(s.length());
append(s);
} // <init>(String)
/** Constructs a string buffer from the specified character array. */
public XMLStringBuffer(char[] ch, int offset, int length) {
this(length);
append(ch, offset, length);
} // <init>(char[],int,int)
/** Constructs a string buffer from the specified XMLString. */
public XMLStringBuffer(XMLString s) {
this(s.length);
append(s);
} // <init>(XMLString)
//
// Public methods
//
/** Clears the string buffer. */
public void clear() {
offset = 0;
length = 0;
}
/**
* append
*
* @param c
*/
public void append(char c) {
if (this.length + 1 > this.ch.length) {
int newLength = this.ch.length*2;
if (newLength < this.ch.length + DEFAULT_SIZE)
newLength = this.ch.length + DEFAULT_SIZE;
char[] newch = new char[newLength];
System.arraycopy(this.ch, 0, newch, 0, this.length);
this.ch = newch;
}
this.ch[this.length] = c;
this.length++;
} // append(char)
/**
* append
*
* @param s
*/
public void append(String s) {
int length = s.length();
if (this.length + length > this.ch.length) {
int newLength = this.ch.length*2;
if (newLength < this.length + length + DEFAULT_SIZE)
newLength = this.ch.length + length + DEFAULT_SIZE;
char[] newch = new char[newLength];
System.arraycopy(this.ch, 0, newch, 0, this.length);
this.ch = newch;
}
s.getChars(0, length, this.ch, this.length);
this.length += length;
} // append(String)
/**
* append
*
* @param ch
* @param offset
* @param length
*/
public void append(char[] ch, int offset, int length) {
if (this.length + length > this.ch.length) {
char[] newch = new char[this.ch.length + length + DEFAULT_SIZE];
System.arraycopy(this.ch, 0, newch, 0, this.length);
this.ch = newch;
}
System.arraycopy(ch, offset, this.ch, this.length, length);
this.length += length;
} // append(char[],int,int)
/**
* append
*
* @param s
*/
public void append(XMLString s) {
append(s.ch, s.offset, s.length);
} // append(XMLString)
} // class XMLStringBuffer
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.
*
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation and was
* originally based on software copyright (c) 1999, International
* Business Machines, Inc., http://www.apache.org. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*/
/**
* This class is used as a structure to pass text contained in the underlying
* character buffer of the scanner. The offset and length fields allow the
* buffer to be re-used without creating new character arrays.
* <p>
* <strong>Note:</strong> Methods that are passed an XMLString structure
* should consider the contents read-only and not make any modifications
* to the contents of the buffer. The method receiving this structure
* should also not modify the offset and length if this structure (or
* the values of this structure) are passed to another method.
* <p>
* <strong>Note:</strong> Methods that are passed an XMLString structure
* are required to copy the information out of the buffer if it is to be
* saved for use beyond the scope of the method. The contents of the
* structure are volatile and the contents of the character buffer cannot
* be assured once the method that is passed this structure returns.
* Therefore, methods passed this structure should not save any reference
* to the structure or the character array contained in the structure.
*
* @author Eric Ye, IBM
* @author Andy Clark, IBM
*
* @version $Id: XMLString.java 515 2008-03-17 21:02:23Z jfrederic.clere@jboss.com $
*/
class XMLString{
//
// Data
//
/** The character array. */
public char[] ch;
/** The offset into the character array. */
public int offset;
/** The length of characters from the offset. */
public int length;
//
// Constructors
//
/** Default constructor. */
public XMLString() {
} // <init>()
/**
* Constructs an XMLString structure preset with the specified
* values.
*
* @param ch The character array.
* @param offset The offset into the character array.
* @param length The length of characters from the offset.
*/
public XMLString(char[] ch, int offset, int length) {
setValues(ch, offset, length);
} // <init>(char[],int,int)
/**
* Constructs an XMLString structure with copies of the values in
* the given structure.
* <p>
* <strong>Note:</strong> This does not copy the character array;
* only the reference to the array is copied.
*
* @param string The XMLString to copy.
*/
public XMLString(XMLString string) {
setValues(string);
} // <init>(XMLString)
//
// Public methods
//
/**
* Initializes the contents of the XMLString structure with the
* specified values.
*
* @param ch The character array.
* @param offset The offset into the character array.
* @param length The length of characters from the offset.
*/
public void setValues(char[] ch, int offset, int length) {
this.ch = ch;
this.offset = offset;
this.length = length;
} // setValues(char[],int,int)
/**
* Initializes the contents of the XMLString structure with copies
* of the given string structure.
* <p>
* <strong>Note:</strong> This does not copy the character array;
* only the reference to the array is copied.
*
* @param s
*/
public void setValues(XMLString s) {
setValues(s.ch, s.offset, s.length);
} // setValues(XMLString)
/** Resets all of the values to their defaults. */
public void clear() {
this.ch = null;
this.offset = 0;
this.length = -1;
} // clear()
/**
* Returns true if the contents of this XMLString structure and
* the specified array are equal.
*
* @param ch The character array.
* @param offset The offset into the character array.
* @param length The length of characters from the offset.
*/
public boolean equals(char[] ch, int offset, int length) {
if (ch == null) {
return false;
}
if (this.length != length) {
return false;
}
for (int i=0; i<length; i++) {
if (this.ch[this.offset+i] != ch[offset+i] ) {
return false;
}
}
return true;
} // equals(char[],int,int):boolean
/**
* Returns true if the contents of this XMLString structure and
* the specified string are equal.
*
* @param s The string to compare.
*/
public boolean equals(String s) {
if (s == null) {
return false;
}
if ( length != s.length() ) {
return false;
}
// is this faster than call s.toCharArray first and compare the
// two arrays directly, which will possibly involve creating a
// new char array object.
for (int i=0; i<length; i++) {
if (ch[offset+i] != s.charAt(i)) {
return false;
}
}
return true;
} // equals(String):boolean
//
// Object methods
//
/** Returns a string representation of this object. */
public String toString() {
return length > 0 ? new String(ch, offset, length) : "";
} // toString():String
} // class XMLString
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