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/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2009-2010 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package org.glassfish.admin.rest.readers;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
/**
* @author rajeshwar patil
*/
public class InputReader {
/**
* Construct a InputReader from a string.
*
* @param reader A reader.
*/
public InputReader(Reader reader) {
this.reader = reader.markSupported() ?
reader : new BufferedReader(reader);
this.useLastChar = false;
this.index = 0;
}
/**
* Construct a InputReader from a string.
*
* @param s A source string.
*/
public InputReader(String s) {
this(new StringReader(s));
}
/**
* Back up one character.
*/
public void back() throws InputException {
if (useLastChar || index <= 0) {
throw new InputException("Stepping back two steps is not supported");
}
index -= 1;
useLastChar = true;
}
/**
* Get the next character in the source string.
*
* @return The next character, or 0 if past the end of the source string.
*/
public char next() throws InputException {
if (this.useLastChar) {
this.useLastChar = false;
if (this.lastChar != 0) {
this.index += 1;
}
return this.lastChar;
}
int c;
try {
c = this.reader.read();
} catch (IOException exc) {
throw new InputException(exc);
}
if (c <= 0) { // End of stream
this.lastChar = 0;
return 0;
}
this.index += 1;
this.lastChar = (char) c;
return this.lastChar;
}
/**
* Resturns InputException to signal a syntax error.
*
* @param message The error message.
* @return A InputException object, suitable for throwing
*/
public InputException error(String message) {
return new InputException(message + toString());
}
/**
* Get the next char in the string, skipping whitespace.
* @throws InputException
* @return A character, or 0 if there are no more characters.
*/
public char nextNonSpace() throws InputException {
for (;;) {
char c = next();
if (c == 0 || c > ' ') {
return c;
}
}
}
/**
* Get the next n characters.
*
* @param n The number of characters to take.
* @return A string of n characters.
* @throws InputException
* Substring bounds error if there are not
* n characters remaining in the source string.
*/
public String next(int n) throws InputException {
if (n == 0) {
return "";
}
char[] buffer = new char[n];
int pos = 0;
if (this.useLastChar) {
this.useLastChar = false;
buffer[0] = this.lastChar;
pos = 1;
}
try {
int len;
while ((pos < n) && ((len = reader.read(buffer, pos, n - pos)) != -1)) {
pos += len;
}
} catch (IOException exc) {
throw new InputException(exc);
}
this.index += pos;
if (pos < n) {
throw error("Substring bounds error");
}
this.lastChar = buffer[n - 1];
return new String(buffer);
}
/**
* Determine if the source string still contains characters that next()
* can consume.
* @return true if not yet at the end of the source.
*/
public boolean more() throws InputException {
char nextChar = next();
if (nextChar == 0) {
return false;
}
back();
return true;
}
private int index;
private Reader reader;
private char lastChar;
private boolean useLastChar;
}