| /* |
| * 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 static org.apache.commons.io.IOUtils.EOF; |
| |
| import java.io.IOException; |
| import java.io.Reader; |
| import java.util.Arrays; |
| import java.util.Iterator; |
| import java.util.Objects; |
| |
| /** |
| * Provides the contents of multiple Readers in sequence. |
| * |
| * @since 2.7 |
| */ |
| public class SequenceReader extends Reader { |
| |
| private Reader reader; |
| private Iterator<? extends Reader> readers; |
| |
| /** |
| * Construct a new instance with readers |
| * |
| * @param readers the readers to read |
| */ |
| public SequenceReader(final Iterable<? extends Reader> readers) { |
| this.readers = Objects.requireNonNull(readers, "readers").iterator(); |
| this.reader = nextReader(); |
| } |
| |
| /** |
| * Construct a new instance with readers |
| * |
| * @param readers the readers to read |
| */ |
| public SequenceReader(final Reader... readers) { |
| this(Arrays.asList(readers)); |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see java.io.Reader#close() |
| */ |
| @Override |
| public void close() throws IOException { |
| this.readers = null; |
| this.reader = null; |
| } |
| |
| /** |
| * Returns the next available reader or null if done. |
| * |
| * @return the next available reader or null |
| */ |
| private Reader nextReader() { |
| return this.readers.hasNext() ? this.readers.next() : null; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see java.io.Reader#read(char[], int, int) |
| */ |
| @Override |
| public int read() throws IOException { |
| int c = EOF; |
| while (reader != null) { |
| c = reader.read(); |
| if (c != EOF) { |
| break; |
| } |
| reader = nextReader(); |
| } |
| return c; |
| } |
| |
| /* |
| * (non-Javadoc) |
| * |
| * @see java.io.Reader#read() |
| */ |
| @Override |
| public int read(final char[] cbuf, int off, int len) throws IOException { |
| Objects.requireNonNull(cbuf, "cbuf"); |
| if (len < 0 || off < 0 || off + len > cbuf.length) { |
| throw new IndexOutOfBoundsException("Array Size=" + cbuf.length + ", offset=" + off + ", length=" + len); |
| } |
| int count = 0; |
| while (reader != null) { |
| final int readLen = reader.read(cbuf, off, len); |
| if (readLen == EOF) { |
| reader = nextReader(); |
| } else { |
| count += readLen; |
| off += readLen; |
| len -= readLen; |
| if (len <= 0) { |
| break; |
| } |
| } |
| } |
| if (count > 0) { |
| return count; |
| } |
| return EOF; |
| } |
| } |