com.prowidesoftware.swift.utils.Lib.java Source code

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Here is the source code for com.prowidesoftware.swift.utils.Lib.java

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/*******************************************************************************
 * Copyright (c) 2016 Prowide Inc.
 *
 *     This program is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU Lesser General Public License as 
 *     published by the Free Software Foundation, either version 3 of the 
 *     License, or (at your option) any later version.
 *
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  
 *     
 *     Check the LGPL at <http://www.gnu.org/licenses/> for more details.
 *******************************************************************************/
package com.prowidesoftware.swift.utils;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;

import org.apache.commons.lang.StringUtils;

/**
 * Miscellaneous helper functions.
 */
public class Lib {
    private Lib() {
    }

    /**
     * Read the content of the given file into a string.
     *
     * @param filename the name of the file to be read
     * @see #readFile(File)
     * @since 7.6
     * @throws IOException if an error occurs during read
     */
    public static String readFile(final String filename) throws IOException {
        return readFile(new File(filename));
    }

    /**
     * Read the content of the given file into a string, usign UTF8 as default encoding
     * @see #readFile(File, String)
     */
    public static String readFile(final File file) throws IOException {
        return readFile(file, "UTF8");
    }

    /**
     * Read the content of the given file into a string.
     *
     * @param file the file to be read
     * @param encoding encoding to use
     * @return the file contents or null if file is null or does not exist, or can't be read, or is not a file
     * @throws IOException if an error occurs during read
     */
    public static String readFile(final File file, final String encoding) throws IOException {
        if (file == null || !file.exists() || !file.canRead() || !file.isFile()) {
            return null;
        }
        BufferedReader in = new BufferedReader(new InputStreamReader(new FileInputStream(file), encoding));
        final StringBuilder sb = new StringBuilder((int) file.length());
        try {
            int c = 0;
            while ((c = in.read()) != -1) {
                sb.append((char) c);
            }
        } finally {
            in.close();
        }
        return sb.toString();
    }

    /**
     * Read a resource from classpath using the context classloader
     * @param resource the resource name to read, must not be null
     * @param encoding optional, may be null in chich case UTF-8 is used
     * @return read content or empty string if resource cannot be loaded
     * @throws IOException
     * @since 7.7
     */
    public static String readResource(final String resource, final String encoding) throws IOException {
        final InputStream is = Thread.currentThread().getContextClassLoader().getResourceAsStream(resource);
        if (is == null) {
            return StringUtils.EMPTY;
        }
        return readStream(is, null);
    }

    /**
     * Read the content of the given stream into a string.
     *
     * @param stream the contents to read
     * @return the read content
     * @see #readStream(InputStream, String)
     * @throws IOException
     * @since 7.7
     */
    public static String readStream(final InputStream stream) throws IOException {
        return readStream(stream, null);
    }

    /**
     * Read the content of the given stream into a string.
     *
     * @param stream the contents to read
     * @param enconding optional encoding to use, if null "UTF-8" is used as default
     * @return the read content
     * @throws IOException
     * @since 7.7
     */
    public static String readStream(final InputStream stream, final String enconding) throws IOException {
        if (stream == null) {
            return null;
        }
        final StringBuilder out = new StringBuilder();
        final String enc = enconding != null ? enconding : "UTF-8";
        final Reader in = new InputStreamReader(stream, enc);
        try {
            int c = 0;
            while ((c = in.read()) != -1) {
                out.append((char) c);
            }
        } finally {
            in.close();
        }
        return out.toString();
    }

    /**
     * Read the content of the given reader into a string.
     *
     * @param reader the contents to read
     * @return the read content
     * @throws IOException
     * @since 7.7
     */
    public static String readReader(final Reader reader) throws IOException {
        if (reader == null) {
            return null;
        }
        final StringBuilder out = new StringBuilder();
        try {
            int c = 0;
            while ((c = reader.read()) != -1) {
                out.append((char) c);
            }
        } finally {
            reader.close();
        }
        return out.toString();
    }
}