com.epam.deltix.util.collections.CharSubSequence Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of timebase-collections Show documentation
Timebase Common utilities and collections
The newest version!
/*
 * Copyright 2021 EPAM Systems, Inc
 *
 * See the NOTICE file distributed with this work for additional information
 * regarding copyright ownership. 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 com.epam.deltix.util.collections;

import com.epam.deltix.util.lang.Util;

/**
 *  Provides implementation-independent equals/hashCode implementation
 *  for comparing instances of CharSequence interface purely based on their
 *  character content. Therefore, equal CharSequences are guaranteed to be equal.
 *  If an instance of CharSequenceKey is added to a Map, the caller is responsible
 *  for keeping the charSequence object immutable.
 */
public final class CharSubSequence implements CharSequence {
    public CharSequence         delegate;
    public int                  start;
    public int                  end;

    public CharSubSequence () {
        delegate = null;
        start = -1;
        end = -1;
    }
    
    public CharSubSequence (CharSequence inDelegate) {
        set (inDelegate);
    }
    
    public CharSubSequence (CharSequence inDelegate, int inStart, int inEnd) {
        set (inDelegate, inStart, inEnd);
    }
    
    public void                 set (CharSequence inDelegate) {
        delegate = inDelegate;
        start = 0;
        end = inDelegate.length ();
    }
    
    public void                 set (CharSequence inDelegate, int inStart, int inEnd) {
        delegate = inDelegate;
        start = inStart;
        end = inEnd;
    }
    
    public final char             charAt (int index) {
        return (delegate.charAt (start + index));
    }

    public final CharSequence     subSequence (int inStart, int inEnd) {
        return (delegate.subSequence (start + inStart, start + inEnd).toString ());
    }

    public final int              length () {
        return (end - start);
    }

    @Override
    public final String           toString () {
        return (delegate.subSequence (start, end).toString ());
    }        
    
    public final void             trimWhitespace () {
        while (start < end && Character.isWhitespace (delegate.charAt (start)))
            start++;

        while (start < end) {
            final int       prev = end - 1;

            if (!Character.isWhitespace (delegate.charAt (prev)))
                break;

            end = prev;
        }  
    }
    
    @Override
    public boolean                  equals (Object other) {
        return (
            this == other ||
            other instanceof CharSequence &&
                Util.equals (this, (CharSequence) other)
        );
    }
    
    @Override
    public int                      hashCode () {
        return (Util.hashCode (this));
    }    
}