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Micro Distribution of the Payara Project
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 1997-2010 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 com.sun.enterprise.admin.cli;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.Reader;
import java.io.Writer;
/**
* Pager.java
*
* @author Toby H Ferguson
*/
class Pager {
private BufferedReader in;
private BufferedWriter out;
private int pageLength;
private String line;
/**
* Construct an object which will copy one pages worth of lines
* at a time from the input to the
* the output.
*
* No attempt is made under any circumstances to close the input
* or output.
*
* @param lines the number of lines in a page. A number less
* than 0 means copy all the input to the output.
* @param in the source of the copy operation
* @param out the destination of the copy operation
* @throws IOException if there's a problem reading from, or
* writing to, the source or destination
*/
Pager(int lines, Reader in, Writer out) throws IOException {
this.in = new BufferedReader(in);
this.out = new BufferedWriter(out);
pageLength = lines;
nextLine();
}
/**
* Copy the next page worth of lines from input to output
*/
void nextPage() throws IOException {
for (int i = 0; (pageLength < 0 || i < pageLength) && hasNext(); i++) {
out.write(line);
out.newLine();
nextLine();
}
out.flush();
}
/**
* Indicate if there are lines left to be copied
* @return true iff there is at least one line left to be copied
*/
boolean hasNext() {
return line != null;
}
/**
* Get the next line and copy it inot the internal buffer so's
* we can answer the hasNext() question
*/
private void nextLine() throws IOException {
line = in.readLine();
}
}