io.jeo.cli.ConsoleProgress.java Source code

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Here is the source code for io.jeo.cli.ConsoleProgress.java

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/* Copyright 2013 The jeo project. 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 io.jeo.cli;

import java.io.PrintStream;
import java.util.Locale;

import jline.console.ConsoleReader;

import com.google.common.base.Strings;

/**
 * Displays progress on the console.
 */
public class ConsoleProgress {

    ConsoleReader console;
    PrintStream output;
    int total;
    int count;

    public ConsoleProgress(ConsoleReader console, PrintStream output, int total) {
        this.console = console;
        this.output = output;
        init(total);
    }

    public ConsoleProgress init(int total) {
        this.total = total;
        count = 0;
        return this;
    }

    /**
     * Increments progress by one unit.
     */
    public ConsoleProgress inc() {
        return inc(1);
    }

    /**
     * Increments progress by the specified amount.
     */
    public ConsoleProgress inc(int amt) {
        count += amt;
        return redraw();
    }

    /**
     * Redraws the progress bar.
     * <p>
     * This method is called from {@link #inc()} so no need to call it explicitly.
     * </p>
     */
    public ConsoleProgress redraw() {
        if (total < 0) {
            return this;
        }

        //number of digits in total to padd count
        int n = (int) (Math.log10(total) + 1);

        StringBuilder sb = new StringBuilder();

        // first encode count/total
        sb.append("[").append(String.format(Locale.ROOT, "%" + n + "d", count)).append("/").append(total)
                .append("]");

        // second is percent
        sb.append(" ").append(String.format(Locale.ROOT, "%3.0f", (count / (float) total * 100))).append("% ");

        //last is progress bar
        int left = console.getTerminal().getWidth() - sb.length() - 2;
        int progress = count * left / total;

        sb.append("[").append(Strings.repeat("=", progress)).append(Strings.repeat(" ", left - progress))
                .append("]");

        output.print(sb.toString() + "\r");
        return this;
    }
}