Interface ConstantPool

All Superinterfaces:
Iterable<PoolEntry>
All Known Subinterfaces:
ClassReader, ConstantPoolBuilder
public sealed interface ConstantPool extends Iterable<PoolEntry> permits ClassReader, ConstantPoolBuilder
Provides read access to the constant pool and the bootstrap method table of a class file.

Index in the Constant Pool

The constant pool entries are accessed by index. A valid index is in the range of [1, size()). It is unusable if a LongEntry or DoubleEntry is at its previous index.
See Java Virtual Machine Specification:
4.4 The Constant Pool
Sealed Class Hierarchy Graph:
Sealed class hierarchy graph for ConstantPoolSealed class hierarchy graph for ConstantPool
Since:
24
See Also:

  • Method Details

    • entryByIndex

      PoolEntry entryByIndex(int index)
      Returns the entry at the specified index.
      API Note:
      If only a particular type of entry is expected, use entryByIndex(int, Class).
      Parameters:
      index - the index within the pool of the desired entry
      Returns:
      the entry at the specified index
      Throws:
      ConstantPoolException - if the index is out of range of the constant pool, or is considered unusable

    • size

      int size()
      Returns the exclusive upper bound of the valid indices of this constant pool. The actual number of entries is lower because 0, size() are not valid, and a valid index may be unusable.
      Returns:
      the exclusive upper bound of the valid indices of this constant pool
      See Also:

    • entryByIndex

      <T extends PoolEntry> T entryByIndex(int index, Class<T> cls)
      Returns the entry of a given type at the specified index.
      Type Parameters:
      T - the entry type
      Parameters:
      index - the index within the pool of the desired entry
      cls - the entry type
      Returns:
      the entry of a given type at the specified index
      Throws:
      ConstantPoolException - if the index is out of range of the constant pool or considered unusable, or the entry is not of the given type

    • iterator

      default Iterator<PoolEntry> iterator()
      Returns an iterator over pool entries.
      Specified by:
      iterator in interface Iterable<PoolEntry>
      API Note:
      This skips any unusable index and is less error-prone than iterating by raw index. See Index in the Constant Pool.
      Returns:
      an iterator over pool entries

    • bootstrapMethodEntry

      BootstrapMethodEntry bootstrapMethodEntry(int index)
      Returns the BootstrapMethodEntry at the specified index within the bootstrap method table.
      Parameters:
      index - the index within the bootstrap method table of the desired entry
      Returns:
      the BootstrapMethodEntry at the specified index within the bootstrap method table
      Throws:
      ConstantPoolException - if the index is out of range of the bootstrap methods

    • bootstrapMethodCount

      int bootstrapMethodCount()
      Returns the number of entries in the bootstrap method table.
      Returns:
      the number of entries in the bootstrap method table