Add CollectionUtil and IO util classes in sentinel-core

sentinel-core/src/main/java/com/alibaba/csp/sentinel/util/CollectionUtil.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 1999-2020 Alibaba Group Holding Ltd.
+ *
+ * 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
+ *
+ *      https://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.alibaba.csp.sentinel.util;
+
+import java.util.Collection;
+import java.util.Map;
+
+/**
+ * @author Eric Zhao
+ * @author lwj
+ * @since 2.0.0
+ */
+public final class CollectionUtil {
+
+    private CollectionUtil() {}
+
+    public static boolean isEmpty(Collection<?> c) {
+        return c == null || c.isEmpty();
+    }
+
+    public static boolean isEmpty(Map<?, ?> c) {
+        return c == null || c.isEmpty();
+    }
+}

sentinel-core/src/main/java/com/alibaba/csp/sentinel/util/io/Charsets.java

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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.alibaba.csp.sentinel.util.io;
+
+import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
+import java.util.Collections;
+import java.util.SortedMap;
+import java.util.TreeMap;
+
+/**
+ * Copy from apache commons-io.
+ */
+public final class Charsets {
+
+    /**
+     * CharEncodingISO Latin Alphabet No. 1, a.k.a. ISO-LATIN-1.
+     * <p>
+     * Every implementation of the Java platform is required to support this character
+     * encoding.
+     * </p>
+     *
+     * @see <a href=
+     * "https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Standard
+     * charsets</a>
+     * @deprecated Use Java 7's {@link StandardCharsets}
+     */
+    @Deprecated
+    public static final Charset ISO_8859_1 = StandardCharsets.ISO_8859_1;
+    /**
+     * <p>
+     * Seven-bit ASCII, also known as ISO646-US, also known as the Basic Latin block of
+     * the Unicode character set.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character
+     * encoding.
+     * </p>
+     *
+     * @see <a href=
+     * "https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Standard
+     * charsets</a>
+     * @deprecated Use Java 7's {@link StandardCharsets}
+     */
+    @Deprecated
+    public static final Charset US_ASCII = StandardCharsets.US_ASCII;
+    /**
+     * <p>
+     * Sixteen-bit Unicode Transformation Format, The byte order specified by a mandatory
+     * initial byte-order mark (either order accepted on input, big-endian used on output)
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character
+     * encoding.
+     * </p>
+     *
+     * @see <a href=
+     * "https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Standard
+     * charsets</a>
+     * @deprecated Use Java 7's {@link StandardCharsets}
+     */
+    @Deprecated
+    public static final Charset UTF_16 = StandardCharsets.UTF_16;
+    /**
+     * <p>
+     * Sixteen-bit Unicode Transformation Format, big-endian byte order.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character
+     * encoding.
+     * </p>
+     *
+     * @see <a href=
+     * "https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Standard
+     * charsets</a>
+     * @deprecated Use Java 7's {@link StandardCharsets}
+     */
+    @Deprecated
+    public static final Charset UTF_16BE = StandardCharsets.UTF_16BE;
+    /**
+     * <p>
+     * Sixteen-bit Unicode Transformation Format, little-endian byte order.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character
+     * encoding.
+     * </p>
+     *
+     * @see <a href=
+     * "https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Standard
+     * charsets</a>
+     * @deprecated Use Java 7's {@link StandardCharsets}
+     */
+    @Deprecated
+    public static final Charset UTF_16LE = StandardCharsets.UTF_16LE;
+    /**
+     * <p>
+     * Eight-bit Unicode Transformation Format.
+     * </p>
+     * <p>
+     * Every implementation of the Java platform is required to support this character
+     * encoding.
+     * </p>
+     *
+     * @see <a href=
+     * "https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">Standard
+     * charsets</a>
+     * @deprecated Use Java 7's {@link StandardCharsets}
+     */
+    @Deprecated
+    public static final Charset UTF_8 = StandardCharsets.UTF_8;
+
+    private Charsets() {
+    }
+
+    /**
+     * Constructs a sorted map from canonical charset names to charset objects required of
+     * every implementation of the Java platform.
+     * <p>
+     * From the Java documentation
+     * <a href="https://docs.oracle.com/javase/7/docs/api/java/nio/charset/Charset.html">
+     * Standard charsets</a>:
+     * </p>
+     *
+     * @return An immutable, case-insensitive map from canonical charset names to charset
+     * objects.
+     * @see Charset#availableCharsets()
+     */
+    public static SortedMap<String, Charset> requiredCharsets() {
+        // maybe cache?
+        final TreeMap<String, Charset> m = new TreeMap<>(String.CASE_INSENSITIVE_ORDER);
+        m.put(StandardCharsets.ISO_8859_1.name(), StandardCharsets.ISO_8859_1);
+        m.put(StandardCharsets.US_ASCII.name(), StandardCharsets.US_ASCII);
+        m.put(StandardCharsets.UTF_16.name(), StandardCharsets.UTF_16);
+        m.put(StandardCharsets.UTF_16BE.name(), StandardCharsets.UTF_16BE);
+        m.put(StandardCharsets.UTF_16LE.name(), StandardCharsets.UTF_16LE);
+        m.put(StandardCharsets.UTF_8.name(), StandardCharsets.UTF_8);
+        return Collections.unmodifiableSortedMap(m);
+    }
+
+    /**
+     * Returns the given Charset or the default Charset if the given Charset is null.
+     *
+     * @param charset A charset or null.
+     * @return the given Charset or the default Charset if the given Charset is null
+     */
+    public static Charset toCharset(final Charset charset) {
+        return charset == null ? Charset.defaultCharset() : charset;
+    }
+
+    /**
+     * Returns a Charset for the named charset. If the name is null, return the default
+     * Charset.
+     *
+     * @param charset The name of the requested charset, may be null.
+     * @return a Charset for the named charset
+     * @throws java.nio.charset.UnsupportedCharsetException If the named charset is
+     * unavailable
+     */
+    public static Charset toCharset(final String charset) {
+        return charset == null ? Charset.defaultCharset() : Charset.forName(charset);
+    }
+
+}

sentinel-core/src/main/java/com/alibaba/csp/sentinel/util/io/FileUtil.java

@@ -0,0 +1,116 @@
+/*
+ * 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.alibaba.csp.sentinel.util.io;
+
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.Charset;
+
+/**
+ * Copy from apache commons-io.
+ */
+public final class FileUtil {
+
+    private FileUtil() {
+    }
+
+    // -----------------------------------------------------------------------
+
+    /**
+     * Opens a {@link FileInputStream} for the specified file, providing better
+     * error messages than simply calling <code>new FileInputStream(file)</code>.
+     * <p>
+     * At the end of the method either the stream will be successfully opened, or an
+     * exception will have been thrown.
+     * <p>
+     * An exception is thrown if the file does not exist. An exception is thrown if the
+     * file object exists but is a directory. An exception is thrown if the file exists
+     * but cannot be read.
+     *
+     * @param file the file to open for input, must not be {@code null}
+     * @return a new {@link FileInputStream} for the specified file
+     * @throws FileNotFoundException if the file does not exist
+     * @throws IOException if the file object is a directory
+     * @throws IOException if the file cannot be read
+     * @since 1.3
+     */
+    public static FileInputStream openInputStream(final File file) throws IOException {
+        if (file.exists()) {
+            if (file.isDirectory()) {
+                throw new IOException("File '" + file + "' exists but is a directory");
+            }
+            if (!file.canRead()) {
+                throw new IOException("File '" + file + "' cannot be read");
+            }
+        } else {
+            throw new FileNotFoundException("File '" + file + "' does not exist");
+        }
+        return new FileInputStream(file);
+    }
+
+    // -----------------------------------------------------------------------
+
+    /**
+     * Reads the contents of a file into a String. The file is always closed.
+     *
+     * @param file     the file to read, must not be {@code null}
+     * @param encoding the encoding to use, {@code null} means platform default
+     * @return the file contents, never {@code null}
+     * @throws IOException in case of an I/O error
+     */
+    public static String readFileToString(final File file, final Charset encoding)
+        throws IOException {
+        try (InputStream in = openInputStream(file)) {
+            return IOUtil.toString(in, Charsets.toCharset(encoding));
+        }
+    }
+
+    /**
+     * Reads the contents of a file into a String. The file is always closed.
+     *
+     * @param file     the file to read, must not be {@code null}
+     * @param encoding the encoding to use, {@code null} means platform default
+     * @return the file contents, never {@code null}
+     * @throws IOException in case of an I/O error
+     * @throws java.nio.charset.UnsupportedCharsetException thrown instead of
+     * {@link java.io .UnsupportedEncodingException} in version 2.2 if the encoding is not
+     * supported.
+     */
+    public static String readFileToString(final File file, final String encoding)
+        throws IOException {
+        return readFileToString(file, Charsets.toCharset(encoding));
+    }
+
+    /**
+     * Reads the contents of a file into a String using the default encoding for the VM.
+     * The file is always closed.
+     *
+     * @param file the file to read, must not be {@code null}
+     * @return the file contents, never {@code null}
+     * @throws IOException in case of an I/O error
+     * @deprecated 2.5 use {@link #readFileToString(File, String)} instead (and specify
+     * the appropriate encoding)
+     */
+    @Deprecated
+    public static String readFileToString(final File file) throws IOException {
+        return readFileToString(file, Charset.defaultCharset());
+    }
+
+}