vaadin-framework/server/src/main/java/com/vaadin/data/util/filter/SimpleStringFilter.java

/*
 * Copyright 2000-2014 Vaadin Ltd.
 * 
 * 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 com.vaadin.data.util.filter;

import com.vaadin.data.Container.Filter;
import com.vaadin.data.Item;
import com.vaadin.data.Property;

/**
 * Simple string filter for matching items that start with or contain a
 * specified string. The matching can be case-sensitive or case-insensitive.
 * 
 * This filter also directly supports in-memory filtering. When performing
 * in-memory filtering, values of other types are converted using toString(),
 * but other (lazy container) implementations do not need to perform such
 * conversions and might not support values of different types.
 * 
 * Note that this filter is modeled after the pre-6.6 filtering mechanisms, and
 * might not be very efficient e.g. for database filtering.
 * 
 * TODO this might still change
 * 
 * @since 6.6
 */
public final class SimpleStringFilter implements Filter {

    final Object propertyId;
    final String filterString;
    final boolean ignoreCase;
    final boolean onlyMatchPrefix;

    public SimpleStringFilter(Object propertyId, String filterString,
            boolean ignoreCase, boolean onlyMatchPrefix) {
        this.propertyId = propertyId;
        this.filterString = ignoreCase ? filterString.toLowerCase()
                : filterString;
        this.ignoreCase = ignoreCase;
        this.onlyMatchPrefix = onlyMatchPrefix;
    }

    @Override
    public boolean passesFilter(Object itemId, Item item) {
        final Property<?> p = item.getItemProperty(propertyId);
        if (p == null) {
            return false;
        }
        Object propertyValue = p.getValue();
        if (propertyValue == null) {
            return false;
        }
        final String value = ignoreCase ? propertyValue.toString()
                .toLowerCase() : propertyValue.toString();
        if (onlyMatchPrefix) {
            if (!value.startsWith(filterString)) {
                return false;
            }
        } else {
            if (!value.contains(filterString)) {
                return false;
            }
        }
        return true;
    }

    @Override
    public boolean appliesToProperty(Object propertyId) {
        return this.propertyId.equals(propertyId);
    }

    @Override
    public boolean equals(Object obj) {
        if (obj == null) {
            return false;
        }

        // Only ones of the objects of the same class can be equal
        if (!(obj instanceof SimpleStringFilter)) {
            return false;
        }
        final SimpleStringFilter o = (SimpleStringFilter) obj;

        // Checks the properties one by one
        if (propertyId != o.propertyId && o.propertyId != null
                && !o.propertyId.equals(propertyId)) {
            return false;
        }
        if (filterString != o.filterString && o.filterString != null
                && !o.filterString.equals(filterString)) {
            return false;
        }
        if (ignoreCase != o.ignoreCase) {
            return false;
        }
        if (onlyMatchPrefix != o.onlyMatchPrefix) {
            return false;
        }

        return true;
    }

    @Override
    public int hashCode() {
        return (propertyId != null ? propertyId.hashCode() : 0)
                ^ (filterString != null ? filterString.hashCode() : 0);
    }

    /**
     * Returns the property identifier to which this filter applies.
     * 
     * @return property id
     */
    public Object getPropertyId() {
        return propertyId;
    }

    /**
     * Returns the filter string.
     * 
     * Note: this method is intended only for implementations of lazy string
     * filters and may change in the future.
     * 
     * @return filter string given to the constructor
     */
    public String getFilterString() {
        return filterString;
    }

    /**
     * Returns whether the filter is case-insensitive or case-sensitive.
     * 
     * Note: this method is intended only for implementations of lazy string
     * filters and may change in the future.
     * 
     * @return true if performing case-insensitive filtering, false for
     *         case-sensitive
     */
    public boolean isIgnoreCase() {
        return ignoreCase;
    }

    /**
     * Returns true if the filter only applies to the beginning of the value
     * string, false for any location in the value.
     * 
     * Note: this method is intended only for implementations of lazy string
     * filters and may change in the future.
     * 
     * @return true if checking for matches at the beginning of the value only,
     *         false if matching any part of value
     */
    public boolean isOnlyMatchPrefix() {
        return onlyMatchPrefix;
    }
}