net.yetamine.pet4bnd.format.Format2Bnd Maven / Gradle / Ivy
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Package exports tracker for bnd.
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/*
* Copyright 2016 Yetamine
*
* 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 net.yetamine.pet4bnd.format;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.nio.charset.StandardCharsets;
import java.time.Clock;
import java.time.Instant;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import java.util.Objects;
import java.util.function.Consumer;
import net.yetamine.pet4bnd.model.Bundle;
import net.yetamine.pet4bnd.model.PackageExport;
import net.yetamine.pet4bnd.model.Persistable;
import net.yetamine.pet4bnd.version.Version;
/**
* Formats a definition to the bnd format.
*/
public final class Format2Bnd implements Persistable {
/** Bundle version header literal. */
private static final String BUNDLE_VERSION_HEADER = "Bundle-Version:";
/** Export header literal. */
private static final String EXPORT_PACKAGE_HEADER = "Export-Package:";
/** Comment to include in the generated files. */
private static final String COMMENT_GENERATOR = "# Generated by the pet4bnd tool";
/** Comment header for generation timestamp. */
private static final String COMMENT_TIMESTAMP = "# ";
/** Indentation for generated file. */
private static final String INDENTATION_TEXT = " ";
/** Size of the indentation for generated files. */
private static final int INDENTATION_SIZE = INDENTATION_TEXT.length();
/** Export bundle version. */
private final Version bundleVersion;
/** Content to format on demand. */
private final List exports;
/** Line length for formatting. */
private final int lineLength;
/** Timestamp source. */
private final Clock timestamp;
/**
* Creates a new instance.
*
* @param definition
* the definition to format. It must not be {@code null}.
* @param bundleVersionOverride
* the bundle version to export or {@code null} if no bundle
* version shall be exported
*/
public Format2Bnd(Bundle definition, Version bundleVersionOverride) {
final Collection packageExports = definition.exports().values();
final List lines = new ArrayList<>(packageExports.size());
lineLength = formatExports(packageExports, lines::add);
exports = Collections.unmodifiableList(lines);
bundleVersion = bundleVersionOverride;
timestamp = Clock.systemUTC();
}
/**
* Creates a new instance from the given instance.
*
* @param source
* the source instance. It must not be {@code null}.
* @param clock
* the clock for the timestamp. It may be {@code null} for no
* timestamp
*/
private Format2Bnd(Format2Bnd source, Clock clock) {
bundleVersion = source.bundleVersion;
lineLength = source.lineLength;
exports = source.exports;
timestamp = clock;
}
/**
* Creates a new instance.
*
* @param definition
* the definition to format. It must not be {@code null}.
* @param renderBundleVersion
* {@code true} if the bundle version shall be exported
*/
public Format2Bnd(Bundle definition, boolean renderBundleVersion) {
this(definition, renderBundleVersion ? definition.version().resolution() : null);
}
/**
* Creates a new instance.
*
* @param definition
* the definition to format. It must not be {@code null}.
*/
public Format2Bnd(Bundle definition) {
this(definition, definition.version().resolution());
}
/**
* Returns a new instance based on this instance that uses the given clock
* for the timestamp.
*
* @param clock
* the clock for the timestamp. It may be {@code null} for no
* timestamp
*
* @return the new instance
*/
public Format2Bnd timestamp(Clock clock) {
return new Format2Bnd(this, clock);
}
/**
* Provides a read-only view on the lines with the exports.
*
* @return the lines with the exports
*/
public List exports() {
return exports;
}
/**
* Stores the encapsulated object in the given sink.
*
* @param sink
* the sink to store the data to. It must not be {@code null}.
*
* @throws IOException
* if storing the object fails
*/
public void persist(BufferedWriter sink) throws IOException {
Objects.requireNonNull(sink);
// Generate the bnd file
sink.write(COMMENT_GENERATOR);
sink.newLine();
if (timestamp != null) {
sink.write(COMMENT_TIMESTAMP);
sink.write(Instant.now(timestamp).toString());
sink.newLine();
}
sink.newLine();
if (bundleVersion != null) {
sink.write(BUNDLE_VERSION_HEADER);
sink.write(' ');
sink.write(bundleVersion.toString());
sink.newLine();
sink.newLine();
}
if (exports.isEmpty()) {
return;
}
sink.write(EXPORT_PACKAGE_HEADER);
// Compute the line end position: include indentation + trailing space to the backslash
final int lineJoinOffset = lineLength + INDENTATION_SIZE - (lineLength % INDENTATION_SIZE);
for (int i = lineJoinOffset - EXPORT_PACKAGE_HEADER.length() + INDENTATION_SIZE; i > 0; i--) {
sink.append(' ');
}
sink.write('\\');
sink.newLine();
// Having the header, continue with the exports
final int last = exports.size() - 1;
for (int i = 0; i < last; i++) {
sink.write(INDENTATION_TEXT);
final String export = exports.get(i);
sink.write(export);
sink.write(',');
// Fill the remaining part to the joining (subtract one more for the comma!)
for (int remaining = lineJoinOffset - export.length(); --remaining > 0;) {
sink.append(' ');
}
// End the line
sink.write('\\');
sink.newLine();
}
// The last export is solved separately to avoid a useless comma
sink.write(INDENTATION_TEXT);
sink.write(exports.get(last));
sink.newLine();
sink.newLine(); // Make a blank line for the case of any continuation
}
/**
* @see net.yetamine.pet4bnd.model.Persistable#persist(java.io.OutputStream)
*/
public void persist(OutputStream sink) throws IOException {
try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(sink, StandardCharsets.UTF_8))) {
persist(writer);
}
}
/**
* Formats the exports into a line sequence.
*
* @param packageExports
* the exports to process. It must not be {@code null}.
* @param lines
* the consumer of the lines. It must not be {@code null}.
*
* @return the maximal length of the lines
*/
private static int formatExports(Iterable packageExports, Consumer lines) {
// Format the packages into lines to capture their length for pretty formatting
int result = EXPORT_PACKAGE_HEADER.length();
for (PackageExport packageExport : packageExports) {
// Build the line with this package's export
final StringBuilder builder = new StringBuilder(packageExport.packageName()).append(';');
builder.append("version=\"").append(packageExport.version().resolution()).append('"');
packageExport.attributes().filter(a -> !a.isEmpty()).ifPresent(a -> {
builder.append(';').append(a);
});
// Record the line and its length
final String export = builder.toString();
result = Math.max(result, export.length());
lines.accept(export);
}
return result;
}
}
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