Java tutorial
/* * 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.facebook.presto.execution; import com.fasterxml.jackson.annotation.JsonCreator; import com.fasterxml.jackson.annotation.JsonValue; import com.google.common.base.Splitter; import com.google.common.collect.ImmutableList; import javax.annotation.concurrent.Immutable; import java.util.List; import java.util.Objects; import java.util.regex.Pattern; import static com.google.common.base.Preconditions.checkArgument; import static java.util.Objects.requireNonNull; @Immutable public class QueryId { @JsonCreator public static QueryId valueOf(String queryId) { List<String> ids = parseDottedId(queryId, 1, "queryId"); return new QueryId(ids.get(0)); } private final String id; public QueryId(String id) { this.id = validateId(id); } public String getId() { return id; } @Override @JsonValue public String toString() { return id; } @Override public int hashCode() { return Objects.hash(id); } @Override public boolean equals(Object obj) { if (this == obj) { return true; } if (obj == null || getClass() != obj.getClass()) { return false; } final QueryId other = (QueryId) obj; return Objects.equals(this.id, other.id); } // // Id helper methods // static final Pattern ID_PATTERN = Pattern.compile("[_a-z0-9]+"); static String validateId(String id) { requireNonNull(id, "id is null"); checkArgument(!id.isEmpty(), "id is empty"); checkArgument(ID_PATTERN.matcher(id).matches(), "Invalid id %s", id); return id; } static List<String> parseDottedId(String id, int expectedParts, String name) { requireNonNull(id, "id is null"); checkArgument(expectedParts > 0, "expectedParts must be at least 1"); requireNonNull(name, "name is null"); ImmutableList<String> ids = ImmutableList.copyOf(Splitter.on('.').split(id)); checkArgument(ids.size() == expectedParts, "Invalid %s %s", name, id); for (String part : ids) { checkArgument(!part.isEmpty(), "Invalid id %s", id); checkArgument(ID_PATTERN.matcher(part).matches(), "Invalid id %s", id); } return ids; } }