com.google.devtools.build.lib.profiler.output.TextPrinter.java Source code

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Here is the source code for com.google.devtools.build.lib.profiler.output.TextPrinter.java

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// Copyright 2015 The Bazel Authors. All rights reserved.
//
// 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.devtools.build.lib.profiler.output;

import com.google.common.base.Preconditions;

import java.io.PrintStream;

/**
 * Utility function for writing text data to a {@link PrintStream}.
 */
public abstract class TextPrinter {

    protected static final String TWO_COLUMN_FORMAT = "%-37s %10s";
    protected static final String THREE_COLUMN_FORMAT = "%-28s %10s %8s";

    private static final String INDENT = "  ";
    protected final PrintStream out;
    private StringBuffer indent;

    protected TextPrinter(PrintStream out) {
        this.out = out;
        this.indent = new StringBuffer();
    }

    /**
     * Increase indentation level
     */
    protected void down() {
        indent.append(INDENT);
    }

    /**
     * Decrease indentation level
     */
    protected void up() {
        Preconditions.checkState(indent.length() >= INDENT.length(),
                "Cannot reduce indentation level, this/a previous call to up() is not matched by down().");
        indent.setLength(indent.length() - INDENT.length());
    }

    protected void print(Object text) {
        out.print(text);
    }

    protected void printLn() {
        out.println();
    }

    /**
     * newline and indent by current indentation level
     */
    protected void lnIndent() {
        printLn();
        out.print(indent);
    }

    /**
     * newline, indent and print the Object
     * @see PrintStream#print(Object)
     */
    protected void lnPrint(Object text) {
        lnIndent();
        out.print(text);
    }

    /**
     * print text and a newline
     */
    protected void printLn(String text) {
        out.print(text);
        printLn();
    }

    /**
     * newline, indent and print the formatted text
     */
    protected void lnPrintf(String format, Object... args) {
        lnIndent();
        out.printf(format, args);
    }

    protected void printf(String format, Object... args) {
        out.printf(format, args);
    }

    /**
     * Represents a double value as either "N/A" if it is NaN, or as a percentage with "%.2f%%".
     * @param relativeValue is assumed to be a ratio of two values and will be multiplied with 100
     *    for output
     */
    public static String prettyPercentage(double relativeValue) {
        if (Double.isNaN(relativeValue)) {
            return "N/A";
        }
        return String.format("%.2f%%", relativeValue * 100);
    }
}