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/*
 * 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 com.signalfx.shaded.apache.commons.io.input;

import static com.signalfx.shaded.apache.commons.io.IOUtils.EOF;

import java.io.IOException;
import java.io.Reader;
import java.io.SequenceInputStream;
import java.io.UncheckedIOException;
import java.util.Arrays;
import java.util.Iterator;
import java.util.Objects;

/**
 * Provides the contents of multiple {@link Reader}s in sequence.
 * 

* Like {@link SequenceInputStream} but for {@link Reader} arguments. *

* * @since 2.7 */ public class SequenceReader extends Reader { private Reader reader; private final Iterator readers; /** * Constructs a new instance with readers * * @param readers the readers to read */ public SequenceReader(final Iterable readers) { this.readers = Objects.requireNonNull(readers, "readers").iterator(); try { this.reader = nextReader(); } catch (final IOException e) { throw new UncheckedIOException(e); } } /** * Constructs 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 { do { // NOPMD // empty } while (nextReader() != null); } /** * Returns the next available reader or null if done. * * @return the next available reader or null. * @throws IOException IOException If an I/O error occurs. */ private Reader nextReader() throws IOException { if (reader != null) { reader.close(); } if (readers.hasNext()) { reader = readers.next(); } else { reader = null; } return reader; } /* * (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; } 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) { nextReader(); } else { count += readLen; off += readLen; len -= readLen; if (len <= 0) { break; } } } if (count > 0) { return count; } return EOF; } }




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