com.google.gerrit.server.ioutil.ColumnFormatter Maven / Gradle / Ivy
// Copyright (C) 2012 The Android Open Source Project
//
// Licensed 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 com.google.gerrit.server.ioutil;
import com.google.gerrit.server.StringUtil;
import java.io.PrintWriter;
/**
* Simple output formatter for column-oriented data, writing its output to a {@link
* java.io.PrintWriter} object. Handles escaping of the column data so that the resulting output is
* unambiguous and reasonably safe and machine parsable.
*/
public class ColumnFormatter {
private char columnSeparator;
private boolean firstColumn;
private final PrintWriter out;
/**
* @param out The writer to which output should be sent.
* @param columnSeparator A character that should serve as the separator token between columns of
* output. As only non-printable characters in the column text are ever escaped, the column
* separator must be a non-printable character if the output needs to be unambiguously parsed.
*/
public ColumnFormatter(final PrintWriter out, final char columnSeparator) {
this.out = out;
this.columnSeparator = columnSeparator;
this.firstColumn = true;
}
/**
* Adds a text string as a new column in the current line of output, taking care of escaping as
* necessary.
*
* @param content the string to add.
*/
public void addColumn(final String content) {
if (!firstColumn) {
out.print(columnSeparator);
}
out.print(StringUtil.escapeString(content));
firstColumn = false;
}
/**
* Finishes the output by flushing the current line and takes care of any other cleanup action.
*/
public void finish() {
nextLine();
out.flush();
}
/**
* Flushes the current line of output and makes the formatter ready to start receiving new column
* data for a new line (or end-of-file). If the current line is empty nothing is done, i.e.
* consecutive calls to this method without intervening calls to {@link #addColumn} will be
* squashed.
*/
public void nextLine() {
if (!firstColumn) {
out.print('\n');
firstColumn = true;
}
}
}