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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 org.apache.dubbo.common.url.component.param;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
public class DynamicValues implements ParamValue {
private volatile String[] index2Value = new String[1];
private final Map value2Index = new ConcurrentHashMap<>();
private int indexSeq = 0;
public DynamicValues(String defaultVal) {
if (defaultVal == null) {
indexSeq += 1;
} else {
add(defaultVal);
}
}
public int add(String value) {
Integer index = value2Index.get(value);
if (index != null) {
return index;
} else {
synchronized (this) {
// thread safe
if (!value2Index.containsKey(value)) {
if (indexSeq == Integer.MAX_VALUE) {
throw new IllegalStateException("URL Param Cache is full.");
}
// copy on write, only support append now
String[] newValues = new String[indexSeq + 1];
System.arraycopy(index2Value, 0, newValues, 0, indexSeq);
newValues[indexSeq] = value;
index2Value = newValues;
value2Index.put(value, indexSeq);
indexSeq += 1;
}
}
}
return value2Index.get(value);
}
@Override
public String getN(int n) {
if (n == -1) {
return null;
}
return index2Value[n];
}
@Override
public int getIndex(String value) {
if (value == null) {
return -1;
}
Integer index = value2Index.get(value);
if (index == null) {
return add(value);
}
return index;
}
}