platform/lang-api/src/com/intellij/codeInsight/lookup/LookupElement.java

   1 /*
   2  * Copyright 2000-2007 JetBrains s.r.o.
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 package com.intellij.codeInsight.lookup;
  17
  18 import com.intellij.codeInsight.completion.InsertionContext;
  19 import com.intellij.codeInsight.completion.PrefixMatcher;
  20 import com.intellij.openapi.util.UserDataHolderBase;
  21 import org.jetbrains.annotations.NotNull;
  22 import org.jetbrains.annotations.Nullable;
  23
  24 import java.util.Collections;
  25 import java.util.Set;
  26
  27 /**
  28  * A typical way to create lookup element is to use {@link com.intellij.codeInsight.lookup.LookupElementBuilder}.
  29  * Another way is to subclass it. Use the latter way only if you need it to implement some additional interface, to modify equals/hashCode
  30  * or other advanced logic
  31  *
  32  * @author peter
  33  */
  34 public abstract class LookupElement extends UserDataHolderBase {
  35   public static final LookupElement[] EMPTY_ARRAY = new LookupElement[0];
  36   private PrefixMatcher myPrefixMatcher = PrefixMatcher.FALSE_MATCHER;
  37
  38   @NotNull
  39   public abstract String getLookupString();
  40
  41   public Set<String> getAllLookupStrings() {
  42     return Collections.singleton(getLookupString());
  43   }
  44
  45   public boolean setPrefixMatcher(@NotNull final PrefixMatcher matcher) {
  46     myPrefixMatcher = matcher;
  47     return isPrefixMatched();
  48   }
  49
  50   public final boolean isPrefixMatched() {
  51     return myPrefixMatcher.prefixMatches(this);
  52   }
  53
  54   @NotNull
  55   public final PrefixMatcher getPrefixMatcher() {
  56     return myPrefixMatcher;
  57   }
  58
  59   @NotNull
  60   public Object getObject() {
  61     return this;
  62   }
  63
  64   public void handleInsert(InsertionContext context) {
  65   }
  66
  67   @Override
  68   public String toString() {
  69     return getLookupString();
  70   }
  71
  72   public void renderElement(LookupElementPresentation presentation) {
  73     presentation.setItemText(getLookupString());
  74   }
  75
  76   @Nullable
  77   public <T> T as(Class<T> aClass) {
  78     //noinspection unchecked
  79     return aClass.isInstance(this) ? (T) this : null;
  80   }
  81 }