| /* |
| * Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved. |
| */ |
| /* |
| * 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.sun.org.apache.bcel.internal.classfile; |
| |
| import com.sun.org.apache.bcel.internal.Const; |
| import java.io.DataInput; |
| import java.io.DataOutputStream; |
| import java.io.IOException; |
| import java.util.HashMap; |
| import java.util.LinkedHashMap; |
| import java.util.Map; |
| |
| /** |
| * Extends the abstract {@link Constant} to represent a reference to a UTF-8 encoded string. |
| * |
| * @see Constant |
| * @LastModified: Jan 2020 |
| */ |
| public final class ConstantUtf8 extends Constant { |
| |
| private static class Cache { |
| |
| private static final boolean BCEL_STATISTICS = false; |
| private static final int MAX_ENTRIES = 20000; |
| private static final int INITIAL_CAPACITY = (int) (MAX_ENTRIES / 0.75); |
| |
| private static final HashMap<String, ConstantUtf8> CACHE = new LinkedHashMap<String, ConstantUtf8>( |
| INITIAL_CAPACITY, 0.75f, true) { |
| |
| private static final long serialVersionUID = -8506975356158971766L; |
| |
| @Override |
| protected boolean removeEldestEntry(final Map.Entry<String, ConstantUtf8> eldest) { |
| return size() > MAX_ENTRIES; |
| } |
| }; |
| |
| // Set the size to 0 or below to skip caching entirely |
| private static final int MAX_ENTRY_SIZE = 200; |
| |
| static boolean isEnabled() { |
| return Cache.MAX_ENTRIES > 0 && MAX_ENTRY_SIZE > 0; |
| } |
| |
| } |
| |
| /** |
| * Clears the cache. |
| * |
| * @since 6.4.0 |
| */ |
| public static synchronized void clearCache() { |
| Cache.CACHE.clear(); |
| } |
| |
| /** |
| * Gets a new or cached instance of the given value. |
| * <p> |
| * See {@link ConstantUtf8} class Javadoc for details. |
| * </p> |
| * |
| * @param value the value. |
| * @return a new or cached instance of the given value. |
| * @since 6.0 |
| */ |
| public static ConstantUtf8 getCachedInstance(final String value) { |
| if (value.length() > Cache.MAX_ENTRY_SIZE) { |
| return new ConstantUtf8(value); |
| } |
| |
| synchronized (ConstantUtf8.class) { // might be better with a specific lock object |
| ConstantUtf8 result = Cache.CACHE.get(value); |
| if (result != null) { |
| return result; |
| } |
| result = new ConstantUtf8(value); |
| Cache.CACHE.put(value, result); |
| return result; |
| } |
| } |
| |
| /** |
| * Gets a new or cached instance of the given value. |
| * <p> |
| * See {@link ConstantUtf8} class Javadoc for details. |
| * </p> |
| * |
| * @param dataInput the value. |
| * @return a new or cached instance of the given value. |
| * @throws IOException if an I/O error occurs. |
| * @since 6.0 |
| */ |
| public static ConstantUtf8 getInstance(final DataInput dataInput) throws IOException { |
| return getInstance(dataInput.readUTF()); |
| } |
| |
| /** |
| * Gets a new or cached instance of the given value. |
| * <p> |
| * See {@link ConstantUtf8} class Javadoc for details. |
| * </p> |
| * |
| * @param value the value. |
| * @return a new or cached instance of the given value. |
| * @since 6.0 |
| */ |
| public static ConstantUtf8 getInstance(final String value) { |
| return Cache.isEnabled() ? getCachedInstance(value) : new ConstantUtf8(value); |
| } |
| |
| private final String value; |
| |
| /** |
| * Initializes from another object. |
| * |
| * @param constantUtf8 the value. |
| */ |
| public ConstantUtf8(final ConstantUtf8 constantUtf8) { |
| this(constantUtf8.getBytes()); |
| } |
| |
| /** |
| * Initializes instance from file data. |
| * |
| * @param dataInput Input stream |
| * @throws IOException |
| */ |
| ConstantUtf8(final DataInput dataInput) throws IOException { |
| super(Const.CONSTANT_Utf8); |
| value = dataInput.readUTF(); |
| } |
| |
| /** |
| * @param value Data |
| */ |
| public ConstantUtf8(final String value) { |
| super(Const.CONSTANT_Utf8); |
| if (value == null) { |
| throw new IllegalArgumentException("Value must not be null."); |
| } |
| this.value = value; |
| } |
| |
| /** |
| * Called by objects that are traversing the nodes of the tree implicitely defined by the contents of a Java class. |
| * I.e., the hierarchy of methods, fields, attributes, etc. spawns a tree of objects. |
| * |
| * @param v Visitor object |
| */ |
| @Override |
| public void accept(final Visitor v) { |
| v.visitConstantUtf8(this); |
| } |
| |
| /** |
| * Dumps String in Utf8 format to file stream. |
| * |
| * @param file Output file stream |
| * @throws IOException |
| */ |
| @Override |
| public void dump(final DataOutputStream file) throws IOException { |
| file.writeByte(super.getTag()); |
| file.writeUTF(value); |
| } |
| |
| /** |
| * @return Data converted to string. |
| */ |
| public String getBytes() { |
| return value; |
| } |
| |
| /** |
| * @param bytes the raw bytes of this UTF-8 |
| * @deprecated (since 6.0) |
| */ |
| @java.lang.Deprecated |
| public void setBytes(final String bytes) { |
| throw new UnsupportedOperationException(); |
| } |
| |
| /** |
| * @return String representation |
| */ |
| @Override |
| public String toString() { |
| return super.toString() + "(\"" + Utility.replace(value, "\n", "\\n") + "\")"; |
| } |
| } |