Groovy example source code file (EmptyRange.java)

This example Groovy source code file (EmptyRange.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

arraylist, closure, comparable, empty, empty, emptyrange, indexoutofboundsexception, object, object, ranges, ranges, string, unsupportedoperationexception, unsupportedoperationexception, util

The Groovy EmptyRange.java source code

/*
 * Copyright 2003-2007 the original author or authors.
 *
 * 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 groovy.lang;

import org.codehaus.groovy.runtime.InvokerHelper;

import java.util.*;

/**
 * Constructing Ranges like 0..<0
 * @author Dierk Koenig
 * @author Edwin Tellman
 */
public class EmptyRange extends AbstractList implements Range {
    
    /**
     * The value at which the range originates (may be <code>null).
     */
    protected Comparable at;

    /**
     * Creates a new {@link EmptyRange}.
     * 
     * @param at the value at which the range starts (may be <code>null).
     */
    public EmptyRange(Comparable at) {
       this.at = at;
    }

    /**
     * {@inheritDoc}
     */
    public Comparable getFrom() {
        return at;
    }

    /**
     * {@inheritDoc}
     */
    public Comparable getTo() {
        return at;
    }

    /**
     * Never true for an empty range.
     * 
     * @return <code>false
     */
    public boolean isReverse() {
        return false;
    }

    /**
     * Never true for an empty range.
     *
     * @return <code>false
     */
    public boolean containsWithinBounds(Object o) {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    public String inspect() {
        return InvokerHelper.inspect(at) + "..<" + InvokerHelper.inspect(at);
    }

    /**
     * {@inheritDoc}
     */
    public String toString() {
        return (null == at) 
            ? "null..<null"
            : at.toString() + "..<" + at.toString();
    }

    /**
     * Always 0 for an empty range.
     * 
     * @return 0
     */
    public int size() {
        return 0;
    }

    /**
     * Always throws <code>IndexOutOfBoundsException for an empty range.
     * 
     * @throws IndexOutOfBoundsException always
     */
    public Object get(int index) {
        throw new IndexOutOfBoundsException("can't get values from Empty Ranges");
    }

    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException always
     */
    public boolean add(Object o) {
        throw new UnsupportedOperationException("cannot add to Empty Ranges");
    }

    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException
     */
    public boolean addAll(int index, Collection c) {
        throw new UnsupportedOperationException("cannot add to Empty Ranges");
    }

    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException
     */
    public boolean addAll(Collection c) {
        throw new UnsupportedOperationException("cannot add to Empty Ranges");
    }
    
    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException
     */
    public boolean remove(Object o) {
        throw new UnsupportedOperationException("cannot remove from Empty Ranges");
    }

    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException
     */
    public Object remove(int index) {
        throw new UnsupportedOperationException("cannot remove from Empty Ranges");
    }

    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException
     */
    public boolean removeAll(Collection c) {
        throw new UnsupportedOperationException("cannot remove from Empty Ranges");
    }

    /**
     * Always throws <code>UnsupportedOperationException for an empty range.
     *
     * @throws UnsupportedOperationException
     */
    public boolean retainAll(Collection c) {
        throw new UnsupportedOperationException("cannot retainAll in Empty Ranges");
    }

     /**
      * Always throws <code>UnsupportedOperationException for an empty range.
      *
     * @throws UnsupportedOperationException
     */
    public Object set(int index, Object element) {
        throw new UnsupportedOperationException("cannot set in Empty Ranges");
    }

    /**
     * Always does nothing for an empty range.
     */
    public void step(int step, Closure closure) {
    }

    /**
     * Always returns an empty list for an empty range.
     */
    public List step(int step) {
        return new ArrayList();
    }
}