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/*
* Copyright 2017 dmfs GmbH
*
* 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 org.dmfs.rfc3986.utils;
import org.dmfs.iterators.AbstractBaseIterator;
import java.util.Iterator;
import java.util.NoSuchElementException;
/**
* An {@link Iterator} that iterates the elements of a CharSequence of a comma (or other character) separated value list .
*
* Example:
*
*
*
* Iterator<CharSequence> i = new Split("a, b,def,123", ',');
* i.next(); // returns "a"
* i.next(); // returns " b"
* i.next(); // returns "def"
* i.next(); // returns "123"
* i.hasNext(); // false
*
*
*
* Iterating an empty CharSequence or a CharSequence without (unquoted) separators will return exactly one element.
*
* Example:
*
*
*
* Iterator<CharSequence> i = new Split("", ',');
* i.next(); // returns ""
* i.hasNext(); // false
*
*
*
* TODO: replace with the implementation in Iterators once it has been released
*
* @author Marten Gajda
*/
public final class Split extends AbstractBaseIterator
{
private final CharSequence mValue;
private final char mSeparator;
private final int mLimit;
private int mLastSeparatorPos = -1;
private int mNextSeparatorPos = -1;
private int mSplitCount;
/**
* Creates an {@link Iterator} that iterates all segments of the given CharSequence which are separated by the given separator.
*
* @param value
* The CharSequence that contains a list of values.
* @param separator
* The separator that separates the values.
*/
public Split(CharSequence value, char separator)
{
this(value, separator, Integer.MAX_VALUE);
}
/**
* Creates an {@link Iterator} that iterates all segments of the given CharSequence which are separated by the given separator.
*
* @param value
* The CharSequence that contains a separated list of values.
* @param separator
* The separator to scan for.
* @param maxSplits
* The maximum number of splits to perform. The iterator will return at most this number +1 elements (the last iterated element containing the rest
* of the {@link CharSequence}.
*/
public Split(CharSequence value, char separator, int maxSplits)
{
mValue = value;
mSeparator = separator;
mLimit = maxSplits;
}
@Override
public boolean hasNext()
{
if (mNextSeparatorPos == -1)
{
findNextSeparator();
}
return mLastSeparatorPos < mValue.length();
}
@Override
public CharSequence next()
{
if (mLastSeparatorPos >= mValue.length())
{
throw new NoSuchElementException("Last element has already been iterated.");
}
if (mNextSeparatorPos == -1)
{
findNextSeparator();
}
CharSequence result = mValue.subSequence(mLastSeparatorPos + 1, mNextSeparatorPos);
findNextSeparator();
return result;
}
/**
* Move {@link #mNextSeparatorPos} to the next (unquoted) separator (or the end of the {@link CharSequence} if no other separator exists in {@link
* #mValue}).
*/
private void findNextSeparator()
{
mLastSeparatorPos = mNextSeparatorPos;
if (mSplitCount >= mLimit)
{
// "fast forward" to the last position of the CharSequence
mNextSeparatorPos = mValue.length();
return;
}
while (++mNextSeparatorPos < mValue.length())
{
char c = mValue.charAt(mNextSeparatorPos);
if (c == mSeparator)
{
// count this split
mSplitCount++;
return;
}
}
}
}