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Commons IO example source code file (CharSequenceReader.java)
The Commons IO CharSequenceReader.java source code/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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.apache.commons.io.input; import java.io.Reader; import java.io.Serializable; /** * {@link Reader} implementation that can read from String, StringBuffer, * StringBuilder or CharBuffer. * <p> * <strong>Note: Supports {@link #mark(int)} and {@link #reset()}. * * @version $Revision: 659817 $ $Date: 2008-05-24 14:23:10 +0100 (Sat, 24 May 2008) $ * @since Commons IO 1.4 */ public class CharSequenceReader extends Reader implements Serializable { private final CharSequence charSequence; private int idx; private int mark; /** * Construct a new instance with the specified character sequence. * * @param charSequence The character sequence, may be <code>null */ public CharSequenceReader(CharSequence charSequence) { this.charSequence = (charSequence != null ? charSequence : ""); } /** * Close resets the file back to the start and removes any marked position. */ @Override public void close() { idx = 0; mark = 0; } /** * Mark the current position. * * @param readAheadLimit ignored */ @Override public void mark(int readAheadLimit) { mark = idx; } /** * Mark is supported (returns true). * * @return <code>true */ @Override public boolean markSupported() { return true; } /** * Read a single character. * * @return the next character from the character sequence * or -1 if the end has been reached. */ @Override public int read() { if (idx >= charSequence.length()) { return -1; } else { return charSequence.charAt(idx++); } } /** * Read the sepcified number of characters into the array. * * @param array The array to store the characters in * @param offset The starting position in the array to store * @param length The maximum number of characters to read * @return The number of characters read or -1 if there are * no more */ @Override public int read(char[] array, int offset, int length) { if (idx >= charSequence.length()) { return -1; } if (array == null) { throw new NullPointerException("Character array is missing"); } if (length < 0 || (offset + length) > array.length) { throw new IndexOutOfBoundsException("Array Size=" + array.length + ", offset=" + offset + ", length=" + length); } int count = 0; for (int i = 0; i < length; i++) { int c = read(); if (c == -1) { return count; } array[offset + i] = (char)c; count++; } return count; } /** * Reset the reader to the last marked position (or the beginning if * mark has not been called). */ @Override public void reset() { idx = mark; } /** * Skip the specified number of characters. * * @param n The number of characters to skip * @return The actual number of characters skipped */ @Override public long skip(long n) { if (n < 0) { throw new IllegalArgumentException( "Number of characters to skip is less than zero: " + n); } if (idx >= charSequence.length()) { return -1; } int dest = (int)Math.min(charSequence.length(), (idx + n)); int count = dest - idx; idx = dest; return count; } /** * Return a String representation of the underlying * character sequence. * * @return The contents of the character sequence */ @Override public String toString() { return charSequence.toString(); } } Other Commons IO examples (source code examples)Here is a short list of links related to this Commons IO CharSequenceReader.java source code file: |
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