FiltersManager.java
/* Copyright 2002-2024 CS GROUP
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS 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.orekit.data;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
/** Manager for {@link DataFilter data filters}.
* <p>
* This manager holds a set of filters and applies all the relevant
* ones by building a stack that transforms a raw {@link DataSource}
* into a processed {@link DataSource}.
* </p>
* @see DataSource
* @see DataFilter
* @author Luc Maisonobe
* @since 11.0
*/
public class FiltersManager {
/** Supported filters. */
private final List<DataFilter> filters;
/** Build an empty manager.
*/
public FiltersManager() {
this.filters = new ArrayList<>();
}
/** Add a data filter.
* @param filter filter to add
* @see #applyRelevantFilters(DataSource)
* @see #clearFilters()
*/
public void addFilter(final DataFilter filter) {
filters.add(filter);
}
/** Remove all data filters.
* @see #addFilter(DataFilter)
*/
public void clearFilters() {
filters.clear();
}
/** Apply all the relevant data filters, taking care of layers.
* <p>
* If several filters can be applied, they will all be applied
* as a stack, even recursively if required. This means that if
* filter A applies to files with names of the form base.ext.a
* and filter B applies to files with names of the form base.ext.b,
* then providing base.ext.a.b.a will result in filter A being
* applied on top of filter B which itself is applied on top of
* another instance of filter A.
* </p>
* @param original original data source
* @return fully filtered data source
* @exception IOException if some data stream cannot be filtered
* @see #addFilter(DataFilter)
* @see #clearFilters()
* @since 9.2
*/
public DataSource applyRelevantFilters(final DataSource original)
throws IOException {
DataSource top = original;
for (boolean filtering = true; filtering;) {
filtering = false;
for (final DataFilter filter : filters) {
final DataSource filtered = filter.filter(top);
if (filtered != top) {
// the filter has been applied, we need to restart the loop
top = filtered;
filtering = true;
break;
}
}
}
return top;
}
}