package org.eclipse.ui.views.navigator;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved.
 */
import org.eclipse.core.resources.IResource;
import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.ui.PlatformUI;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
import java.io.StringBufferInputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.StringTokenizer;

/**
 * The ResourcePatternFilter is the filter used to determine whether resources are
 * to be shown or not.
 */
/* package */ class ResourcePatternFilter extends ViewerFilter {
	private String[] patterns;
	private StringMatcher[] matchers;
	
	static String COMMA_SEPARATOR = ",";//$NON-NLS-1$
	static String FILTERS_TAG = "resourceFilters";//$NON-NLS-1$
/**
 * Creates a new resource pattern filter.
 */
public ResourcePatternFilter() {
	super();
}
/**
 * Return the currently configured StringMatchers. If there aren't any look
 * them up.
 */
private StringMatcher[] getMatchers() {

	if (this.matchers == null)
		initializeFromPreferences();

	return this.matchers;
}
/**
 * Gets the patterns for the receiver. Returns the cached values if there
 * are any - if not look it up.
 */
public String[] getPatterns() {

	if (this.patterns == null)
		initializeFromPreferences();

	return this.patterns;

}
/**
 * Initialize the settings from the workbench preferences.
 */
private void initializeFromPreferences() {

	AbstractUIPlugin plugin =
		(AbstractUIPlugin) Platform.getPlugin(PlatformUI.PLUGIN_ID);

	String storedPatterns = plugin.getPreferenceStore().getString(FILTERS_TAG);

	if (storedPatterns.length() == 0) {
		List defaultFilters = FiltersContentProvider.getDefaultFilters();
		String[] patterns = new String[defaultFilters.size()];
		defaultFilters.toArray(patterns);
		setPatterns(patterns);
		return;
	}

	//Get the strings separated by a comma and filter them from the currently
	//defined ones

	List definedFilters = FiltersContentProvider.getDefinedFilters();

	StringTokenizer entries = new StringTokenizer(storedPatterns, COMMA_SEPARATOR);
	List patterns = new ArrayList();

	while (entries.hasMoreElements()) {
		String nextToken = entries.nextToken();
		if (definedFilters.indexOf(nextToken) > -1)
			patterns.add(nextToken);
	}

	//Convert to an array of Strings
	String[] patternArray = new String[patterns.size()];
	patterns.toArray(patternArray);
	setPatterns(patternArray);

}
/* (non-Javadoc)
 * Method declared on ViewerFilter.
 */
public boolean select(Viewer viewer, Object parentElement, Object element) {
	IResource resource = null;
	if (element instanceof IResource) {
		resource = (IResource) element;
	} else
		if (element instanceof IAdaptable) {
			IAdaptable adaptable = (IAdaptable) element;
			resource = (IResource) adaptable.getAdapter(IResource.class);
		}
	if (resource != null) {
		String name = resource.getName();
		StringMatcher[] testMatchers = getMatchers();
		for (int i = 0; i < testMatchers.length; i++) {
			if (testMatchers[i].match(name))
				return false;
		}
		return true;
	}
	return true;
}
/**
 * Sets the patterns to filter out for the receiver.
 */
public void setPatterns(String[] newPatterns) {

	this.patterns = newPatterns;
	this.matchers = new StringMatcher[newPatterns.length];
	for (int i = 0; i < newPatterns.length; i++) {
		//Reset the matchers to prevent constructor overhead
		matchers[i] = new StringMatcher(newPatterns[i], true, false);
	}
}
}