Java tutorial
/*license*\ XBN-Java: Copyright (C) 2014, Jeff Epstein (aliteralmind __DASH__ github __AT__ yahoo __DOT__ com) This software is dual-licensed under the: - Lesser General Public License (LGPL) version 3.0 or, at your option, any later version; - Apache Software License (ASL) version 2.0. Either license may be applied at your discretion. More information may be found at - http://en.wikipedia.org/wiki/Multi-licensing. The text of both licenses is available in the root directory of this project, under the names "LICENSE_lgpl-3.0.txt" and "LICENSE_asl-2.0.txt". The latest copies may be downloaded at: - LGPL 3.0: https://www.gnu.org/licenses/lgpl-3.0.txt - ASL 2.0: http://www.apache.org/licenses/LICENSE-2.0.txt \*license*/ package com.github.xbn.text; import com.github.xbn.io.RTIOException; import com.github.xbn.lang.CrashIfObject; import java.io.BufferedReader; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.InputStreamReader; import java.util.Iterator; import java.util.NoSuchElementException; import org.apache.commons.io.LineIterator; /** <p>Duplicate a str_obj, append a str_obj if a condition is met, get a "visible index mask", and other str_obj-related utilities.</p> * @since 0.1.0 * @author Copyright (C) 2014, Jeff Epstein ({@code aliteralmind __DASH__ github __AT__ yahoo __DOT__ com}), dual-licensed under the LGPL (version 3.0 or later) or the ASL (version 2.0). See source code for details. <a href="http://xbnjava.aliteralmind.com">{@code http://xbnjava.aliteralmind.com}</a>, <a href="https://github.com/aliteralmind/xbnjava">{@code https://github.com/aliteralmind/xbnjava}</a> **/ public class StringUtil extends StringUtilBase { private StringUtil() { throw new IllegalStateException("Do not instantiate"); } /** <p>An iterator for the characters in a str_obj.</p> */ public static final Iterator<Character> getCharIterator(Object str_toPad) { return (new CharIteratorForQ(str_toPad)); } /** <p>Get one str_obj if a condition is met, another if it's not.</p> * @return <code>{@link #appendIfTrueFalse(Appendable, Object, boolean, Object) appendIfTrueFalse}((new StringBuilder()), true_oString, condition, oString_ifFalse).toString()</code> */ public static final String getIfTrueFalse(Object true_oString, boolean condition, Object oString_ifFalse) { return appendIfTrueFalse((new StringBuilder()), true_oString, condition, oString_ifFalse).toString(); } /** <p>Get one str_obj if a condition is met, another if it's not.</p> * @param to_appendTo May not be {@code null}. * @param true_oString Returned if {@code condition} is {@code true}. * @param oString_ifFalse Returned if {@code condition} is {@code false}. * @exception RTIOException If an {@link java.io.IOException IOException} is thrown * @see #getIfTrueFalse(Object, boolean, Object) getIfTrueFalse(O,b,O) */ public static final Appendable appendIfTrueFalse(Appendable to_appendTo, Object true_oString, boolean condition, Object oString_ifFalse) { try { if (condition) { if (true_oString != null) { to_appendTo.append(true_oString.toString()); } } else if (oString_ifFalse != null) { to_appendTo.append(oString_ifFalse.toString()); } } catch (IOException iox) { throw new RTIOException("appendIfTrueFalse", iox); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(to_appendTo, "to_appendTo", null, rx); } return to_appendTo; } /** <p>Get one str_obj (with a prefix and postfix) if a condition is met, or another if it's not.</p> * @return <code>{@link #appendPreTruePostOrFalse(Appendable, String, Object, String, boolean, Object) appendPreTruePostOrFalse}((new StringBuilder()), prefix_ifTrue, true_oString, postfix_ifTrue, condition, oString_ifFalse).toString()</code> */ public static final String getPreTruePostOrFalse(String prefix_ifTrue, Object true_oString, String postfix_ifTrue, boolean condition, Object oString_ifFalse) { return appendPreTruePostOrFalse((new StringBuilder()), prefix_ifTrue, true_oString, postfix_ifTrue, condition, oString_ifFalse).toString(); } /** <p>Append one str_obj (with a prefix and postfix) if a condition is met, or another if it's not.</p> * @exception RTIOException If an {@link java.io.IOException IOException} is thrown */ public static final Appendable appendPreTruePostOrFalse(Appendable to_appendTo, String prefix_ifTrue, Object true_oString, String postfix_ifTrue, boolean condition, Object oString_ifFalse) { try { if (condition) { if (prefix_ifTrue != null) { to_appendTo.append(prefix_ifTrue); } if (true_oString != null) { to_appendTo.append(true_oString.toString()); } if (postfix_ifTrue != null) { to_appendTo.append(postfix_ifTrue); } } else if (oString_ifFalse != null) { to_appendTo.append(oString_ifFalse.toString()); } } catch (IOException iox) { throw new RTIOException("appendPreTruePostOrFalse", iox); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(to_appendTo, "to_appendTo", null, rx); } return to_appendTo; } /** <p>Eliminate whitespace from the left side of a str_obj.</p> <p>The idea for this and {@code rtrim(str_toPad)} is from <br/> <code><a href="http://stackoverflow.com/questions/15567010/what-is-a-good-alternative-of-ltrim-and-rtrim-in-java">http://stackoverflow.com/questions/15567010/what-is-a-good-alternative-of-ltrim-and-rtrim-in-java</a></code> <br/>and <br/> <code><a href="http://www.fromdev.com/2009/07/playing-with-java-str_obj-trim-basics.html">http://www.fromdev.com/2009/07/playing-with-java-str_obj-trim-basics.html</a></code> <br/>(viewed 11/18/2013)</p> * @param str_toPad May not be {@code null}. * @see #rtrim(Object) rtrim(o) */ public static String ltrim(Object str_toPad) { String s = null; try { s = str_toPad.toString(); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(str_toPad, "str_toPad", null, rx); } int i = 0; while (i < s.length() && Character.isWhitespace(s.charAt(i))) { i++; } return s.substring(i); } /** <p>Eliminate whitespace from the right side of a str_obj.</p> * @param str_toPad May not be {@code null}. * @see #ltrim(Object) ltrim(o) */ public static String rtrim(Object str_toPad) { String s = null; try { s = str_toPad.toString(); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(str_toPad, "str_toPad", null, rx); } int i = s.length() - 1; while (i >= 0 && Character.isWhitespace(s.charAt(i))) { i--; } return s.substring(0, (i + 1)); } /** <p>Creates a string where every element is the same character.</p> * @param length The length of the returned string. * @param char_toDup The character to duplicate. * @param length_varName Descriptive name of {@code length}. <i>Should</i> not be {@code null} or empty. * @return <code>new String(new char[length]).java.lang.String#replace(CharSequence, CharSequence)("\0", (new Character(char_toDup)).toString())</code> * @see <code><a href="http://stackoverflow.com/questions/1235179/simple-way-to-repeat-a-string-in-java/4903603#4903603">http://stackoverflow.com/questions/1235179/simple-way-to-repeat-a-string-in-java/4903603#4903603</a></code> * @exception NegativeArraySizeException If {@code length} is less than zero. */ public static final String getStringOfLengthAllCharsEqualTo(int length, char char_toDup, String length_varName) { try { return new String(new char[length]).replace("\0", (new Character(char_toDup)).toString()); } catch (NegativeArraySizeException nasx) { throw new NegativeArraySizeException(length_varName + "=" + length); } } /** <p>For visibly indicating the index or index-range of a str_obj on the immediately-above line.</p> {@.codelet.and.out com.github.xbn.examples.text.VisibleIndexMaskXmpl%eliminateCommentBlocksAndPackageDecl()} * @param str_toPadForLen The str_obj to mask. * @param idx_start The mask-start index. <i>Should</i> be between 0 and <br/> {@code (str_toPadForLen.toString().length() - 1)} * @param idx_endX The mask-end index. <i>Should</i> be between {@code (idx_start + 1)} and <br/> {@code str_toPadForLen.toString().length()}. */ public static final String getVisibleIndexMask(Object str_toPadForLen, int idx_start, int idx_endX) { StringBuilder sd = new StringBuilder(getDuped(" ", idx_start)); if (idx_start == idx_endX) { sd.append("^"); } else { sd.append("|").append(getDuped("-", (idx_endX - idx_start - 1))).append("|"); } try { sd.append(getDuped(" ", (str_toPadForLen.toString().length() - idx_endX))); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(str_toPadForLen, "str_toPadForLen", null, rx); } return sd.toString(); } /** <p>Get a str_obj, duplicated.</p> * @param str_toDup The str_obj to duplicate. May not be {@code null} or empty. * @param dup_count The number of times to duplicate {@code str_toDup}. May not be less than zero. If zero, an empty str_obj is returned. * @return <code>{@link #appendDuped(Appendable, Object, int) appendDuped}((new StringBuilder()), str_toDup, dup_count).toString()</code> */ public static final String getDuped(Object str_toDup, int dup_count) { return appendDuped((new StringBuilder()), str_toDup, dup_count).toString(); } /** <p>Append a str_obj, duplicated.</p> * @param to_appendTo May not be {@code null}. * @param str_toDup Descriptive name of {@code to_appendTo}. <i>Should</i> not be {@code null} or empty. * @param dup_count <i>Should</i> be greater than zero. * @exception RTIOException If an {@link java.io.IOException IOException} is thrown. * @see #getDuped(Object, int) getDuped(O,i) */ public static final Appendable appendDuped(Appendable to_appendTo, Object str_toDup, int dup_count) { try { CrashIfString.nullEmpty(str_toDup, "str_toDup", null); String s = str_toDup.toString(); for (int i = 0; i < dup_count; i++) { to_appendTo.append(s); } } catch (IOException iox) { throw new RTIOException(iox); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(to_appendTo, "to_appendTo", null, rx); } return to_appendTo; } public static final Iterator<String> getLineIterator(Object string_obj) { BufferedReader br = null; try { br = new BufferedReader( new InputStreamReader(new ByteArrayInputStream(string_obj.toString().getBytes()))); } catch (RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(string_obj, "string_obj", null, rx); } return new LineIterator(br); } /* public static final boolean isEqualToExactlyOneElement(String to_test, String[] all_possibleValues, IgnoreCase ignore_case) { try { to_test = ignore_case.toUpperCaseIfYes(to_test, "to_test"); } catch(RuntimeException rx) { throw CrashIfObject.nullOrReturnCause(ignore_case, "ignore_case", null, rx); } int i = 0; try { for(; i < all_possibleValues.length; i++) { if(ignore_case.toUpperCaseIfYes(all_possibleValues[i], null).equals(to_test)) { return true; } } } catch(RuntimeException rx) { CrashIfObject.nnull(all_possibleValues, "all_possibleValues", null); throw CrashIfObject.nullOrReturnCause(all_possibleValues[i], "all_possibleValues[" + i + "]", null, rx); } return false; } */ } class CharIteratorForQ implements Iterator<Character> { private CharSequence q = null; private int ix = -1; //constructors...START public CharIteratorForQ(Object str_toPad) { this((String) str_toPad); } public CharIteratorForQ(CharSequence cs) { if (cs == null) { throw new NullPointerException("cs"); } q = cs; ix = 0; } //constructors...END public boolean hasNext() { return (ix < q.length()); } public Character next() { if (!hasNext()) { throw new NoSuchElementException( "The length of the str_obj is " + q.length() + ". The str_obj: \"" + q + "\""); } return q.charAt(ix++); } /** <p><i>Do not use.</i></p> * @exception UnsupportedOperationException */ public void remove() { throw new UnsupportedOperationException("remove()"); } }