Object Stack
/* * @(#)$Id: ObjectStack.java 3619 2008-03-26 07:23:03Z yui $ * * Copyright 2006-2008 Makoto YUI * * 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. * * Contributors: * Makoto YUI - initial porting *///package xbird.util.collections; import java.io.Serializable; /** * Light-weight ObjectStack implementation. * <DIV lang="en"></DIV> * <DIV lang="ja"></DIV> * * @author Makoto YUI (yuin405+xbird@gmail.com) */publicfinalclass ObjectStack implements Serializable { privatestaticfinallong serialVersionUID = -1652603821997551249L; publicstaticfinalint DEFAULT_SIZE = 12; private Object[] stack; privateint counter = 0; public ObjectStack() { this(DEFAULT_SIZE); } public ObjectStack(int size) { this.stack = new Object[size]; } publicvoid push(Object value) { ensureCapacity(counter + 1); stack[counter++] = value; } public Object pop() { Object poped = stack[--counter]; stack[counter] = null; return poped; } public Object get(int at) { if(at >= counter || at < 0) { thrownew IllegalArgumentException("Out of index: " + at); } return stack[at]; } publicboolean isEmpty() { return counter == 0; } publicint size() { return counter; } public Object peek() { return counter == 0 ? null : stack[counter - 1]; } publicvoid clear() { for(int i = 0; i < counter; i++) { stack[i] = null; } counter = 0; } @Override public String toString() { final StringBuilder buf = new StringBuilder(); buf.append('['); for(int i = 0; i < counter; i++) { if (i != 0) { buf.append(", "); } buf.append(stack[i]); } buf.append(']'); return buf.toString(); } privatevoid ensureCapacity(int minCapacity) { int oldCapacity = stack.length; if (minCapacity > oldCapacity) { int newCapacity = oldCapacity * 2; if (newCapacity < minCapacity) { newCapacity = minCapacity; } Object[] newStack = new Object[newCapacity]; System.arraycopy(stack, 0, newStack, 0, counter); this.stack = newStack; } } } Related examples in the same category
