String search and reflection helper methods : Array Compare « Collections Data Structure « Java

1. Java
2. Collections Data Structure
3. Array Compare

String search and reflection helper methods

/** * The utillib library. * More information is available at http://www.jinchess.com/. * Copyright (C) 2002, 2003 Alexander Maryanovsky. * All rights reserved. * * The utillib library 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 2 of the * License, or (at your option) any later version. * * The utillib library 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. See the GNU Lesser * General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with utillib library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA */import java.util.Hashtable; import java.util.Enumeration; import java.util.NoSuchElementException; /** * A collection of general utility methods. */publicclass Utilities{ /** * A 0-length Object array. */publicstaticfinal Object [] EMPTY_ARRAY = new Object[0]; /** * A 0-length long array. */publicstaticfinallong [] EMPTY_LONG_ARRAY = newlong[0]; /** * A 0-length int array. */publicstaticfinalint [] EMPTY_INT_ARRAY = newint[0]; /** * A 0-length short array. */publicstaticfinalshort [] EMPTY_SHORT_ARRAY = newshort[0]; /** * A 0-length byte array. */publicstaticfinalbyte [] EMPTY_BYTE_ARRAY = newbyte[0]; /** * A 0-length char array. */publicstaticfinalchar [] EMPTY_CHAR_ARRAY = newchar[0]; /** * A 0-length double array. */publicstaticfinaldouble [] EMPTY_DOUBLE_ARRAY = newdouble[0]; /** * A 0-length float array. */publicstaticfinalfloat [] EMPTY_FLOAT_ARRAY = newfloat[0]; /** * A 0-length String array. */publicstaticfinal String [] EMPTY_STRING_ARRAY = new String[0]; /** * An empty enumeration. */publicstaticfinal Enumeration EMPTY_ENUM = new Enumeration(){ publicboolean hasMoreElements(){return false;} public Object nextElement(){thrownew NoSuchElementException();} }; /** * Returns <code>true</code> if the two specified objects are the same. * Returns <code>false</code> otherwise. To be considered the same, the two * references must either both be null or invoking <code>equals</code> on one * of them with the other must return <code>true</code>. */publicstaticboolean areEqual(Object obj1, Object obj2){ return (obj1 == obj2) || (obj1 == null ? false : obj1.equals(obj2)); } /** * Maps the specified key to the specified value in the specified * <code>Hashtable</code>. If the specified value is <code>null</code> any * existing mapping of the specified key is removed from the * <code>Hashtable</code>. The old value mapped to the specified key * is returned, or <code>null</code> if no value was mapped to the key. */publicstatic Object put(Hashtable table, Object key, Object value){ return value == null ? table.remove(key) : table.put(key, value); } /** * Returns <code>true</code> if the specified object is an element of the * specified array. The specified array may not be <code>null</code>. The * specified object may be <code>null</code>, in which case this method will * return <code>true</code> iff one of the indices in the array is empty * (contains <code>null</code>). */publicstaticboolean contains(Object [] array, Object item){ return (indexOf(array, item) != -1); } /** * Returns the index of the first occurrance of specified object in the * specified array, or -1 if the specified object is not an element of the * specified array. The specified object may be <code>null</code> in which * case the returned index will be the index of the first <code>null</code> * in the array. */publicstaticint indexOf(Object [] array, Object item){ if (array == null) thrownew IllegalArgumentException("The specified array may not be null"); for (int i = 0; i < array.length; i++) if (areEqual(item, array[i])) return i; return -1; } /** * Returns the index of the first occurrance of specified integer in the * specified array, or -1 if the specified integer is not an element of the * specified array. */publicstaticint indexOf(int [] arr, int val){ if (arr == null) thrownew IllegalArgumentException("The specified array may not be null"); for (int i = 0; i < arr.length; i++) if (arr[i] == val) return i; return -1; } /** * Converts the specified array into a string by appending all its elements * separated by a semicolon. */publicstatic String arrayToString(Object [] arr){ StringBuffer buf = new StringBuffer(); for (int i = 0; i < arr.length; i++){ buf.append(arr[i]); buf.append("; "); } if (arr.length > 0) buf.setLength(buf.length() - 2); // get rid of the extra "; " return buf.toString(); } /** * Converts the specified <code>Hashtable</code> into a string by putting * each key and value on a separate line (separated by '\n') and an arrow * (" -> ") between them. */publicstatic String hashtableToString(Hashtable hashtable){ StringBuffer buf = new StringBuffer(); Enumeration keys = hashtable.keys(); while (keys.hasMoreElements()){ Object key = keys.nextElement(); Object value = hashtable.get(key); buf.append(key.toString()); buf.append(" -> "); buf.append(value.toString()); buf.append("\n"); } return buf.toString(); } /** * Returns the maximum element in the specified integer array. */publicstaticint max(int [] arr){ if (arr == null) thrownew IllegalArgumentException("The specified array may not be null"); if (arr.length == 0) thrownew IllegalArgumentException("The specified array must have at least one element"); int n = arr[0]; for (int i = 1; i < arr.length; i++) if (arr[i] > n) n = arr[i]; return n; } /** * Returns a hash code for the specified double value. */publicstaticint hashCode(double val){ return hashCode(Double.doubleToLongBits(val)); } /** * Returns a hash code for the specified long value. */publicstaticint hashCode(long val){ return (int)(val ^ (val >>> 32)); } /** * Returns the name of the package of the specified class. */publicstatic String getPackageName(Class c){ return getPackageName(c.getName()); } /** * Returns the name of the package of the class with the specified (full) name. */publicstatic String getPackageName(String className){ int lastDotIndex = className.lastIndexOf("."); return lastDotIndex == -1 ? "" : className.substring(0, lastDotIndex); } /** * Returns the short name (excluding the package name) of the specified class. */publicstatic String getClassName(Class c){ return getClassName(c.getName()); } /** * Returns the short name (excluding the package name) of the class with the * specified fully qualified name. */publicstatic String getClassName(String className){ int lastDotIndex = className.lastIndexOf("."); return lastDotIndex == -1 ? className : className.substring(lastDotIndex + 1); } } 

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