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/*
* Copyright 2015 Google Inc.
*
* 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
*
* 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 java.util;
/**
* See
* the official Java API doc for details.
*/
public final class StringJoiner {
private final String delimiter;
private final String prefix;
private final String suffix;
private StringBuilder builder;
private String emptyValue;
public StringJoiner(CharSequence delimiter) {
this(delimiter, "", "");
}
public StringJoiner(CharSequence delimiter, CharSequence prefix, CharSequence suffix) {
this.delimiter = delimiter.toString();
this.prefix = prefix.toString();
this.suffix = suffix.toString();
this.emptyValue = this.prefix + this.suffix;
}
public StringJoiner add(CharSequence newElement) {
initBuilderOrAddDelimiter();
builder.append(newElement);
return this;
}
public int length() {
if (builder == null) {
return emptyValue.length();
}
return builder.length() + suffix.length();
}
public StringJoiner merge(StringJoiner other) {
if (other.builder != null) {
// in case of other == this we need the length before adding delimiter to this (and thus other)
// so we can skip the trailing delimiter of other when merging into this.
int otherLength = other.builder.length();
initBuilderOrAddDelimiter();
builder.append(other.builder, other.prefix.length(), otherLength);
}
return this;
}
public StringJoiner setEmptyValue(CharSequence emptyValue) {
this.emptyValue = emptyValue.toString();
return this;
}
@Override
public String toString() {
if (builder == null) {
return emptyValue;
} else if (suffix.isEmpty()) {
return builder.toString();
} else {
return builder.toString() + suffix;
}
}
private void initBuilderOrAddDelimiter() {
if (builder == null) {
builder = new StringBuilder(prefix);
} else {
builder.append(delimiter);
}
}
}