96 lines
2.1 KiB
Java
96 lines
2.1 KiB
Java
/*
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* Copyright (C) 2008 The Guava Authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package com.google.common.io;
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import java.io.IOException;
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import java.io.Reader;
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import java.util.Iterator;
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import javax.annotation.Nullable;
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import com.google.common.base.Preconditions;
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/**
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* A {@link Reader} that concatenates multiple readers.
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*
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* @author Bin Zhu
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* @since 1.0
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*/
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class MultiReader extends Reader {
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private final Iterator<? extends CharSource> it;
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private Reader current;
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MultiReader(Iterator<? extends CharSource> readers) throws IOException {
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this.it = readers;
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advance();
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}
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/**
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* Closes the current reader and opens the next one, if any.
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*/
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private void advance() throws IOException {
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close();
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if (it.hasNext()) {
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current = it.next().openStream();
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}
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}
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@Override
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public int read(@Nullable char cbuf[], int off, int len) throws IOException {
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if (current == null) {
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return -1;
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}
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int result = current.read(cbuf, off, len);
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if (result == -1) {
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advance();
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return read(cbuf, off, len);
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}
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return result;
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}
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@Override
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public long skip(long n) throws IOException {
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Preconditions.checkArgument(n >= 0, "n is negative");
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if (n > 0) {
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while (current != null) {
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long result = current.skip(n);
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if (result > 0) {
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return result;
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}
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advance();
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}
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}
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return 0;
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}
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@Override
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public boolean ready() throws IOException {
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return (current != null) && current.ready();
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}
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@Override
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public void close() throws IOException {
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if (current != null) {
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try {
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current.close();
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} finally {
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current = null;
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}
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}
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}
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}
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